BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Injection of Atomic Hydrogen from a Thermal Cracker Cell to Plasma Grid Surface of H- Ion Source DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-296@indico.inp.nsk.su DESCRIPTION:Speakers: Yuji Shimabukuro (Doshisha University)\nThe principl e mechanism of the negative hydrogen (H$^-$) ion current enhancement due t o Cs injection can be attributable to the reflection of atomic hydrogen at low work function plasma grid surface. To directly confirm the contribut ion of atomic hydrogen (H$^0$) flux in the actual ion source operating con dition\, H$^0$ sources of different types are attached to a small multicus p type H$^-$ ion source. Our previous work using a microwave driven atomi c source revealed that low energy H$^0$ injection into a cesiated hydrogen plasma resulted in reduction in H$^-$ ion current despite the original ex pectation. The possible reason can be the inadequate formation of surface produced H$^-$ by H$^0$ injection that did not surpass the destruction of H$^-$ due to injected H$^0$. In this report\, high temperature hydrogen atoms formed in a thermal cracking cell strike the plasma grid surface of the H$^-$ ion source. The velocity distribution from this type of atom so urce can be broader than the microwave atom source\, and H$^-$ can be surf ace produced with higher efficiency due to the high velocity component in the velocity distribution. The H$^-$ current and the co-extracted electro n current are compared for the conditions with and without Cs supply. Unl ike the hydrogen atoms produced in the microwave discharge\, it was observ ed that thermal hydrogen atoms destroyed the volume produced H$^-$ ions in the certain condition without Cs. We will report the effect of H$^0$ inj ection by thermal cracker cell to compare with the effect due to low energ y H$^0$ injection from a microwave discharge cell. The effects will be in vestigated under both condition with and without Cs coverage.\n\nhttps://i ndico.inp.nsk.su/event/11/contributions/296/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/296/ END:VEVENT BEGIN:VEVENT SUMMARY:Study of the Materials on Plasma Electrode Surface for Negative Io n Extraction in Hydrogen and Deuterium Operation DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-297@indico.inp.nsk.su DESCRIPTION:Speakers: Shingo Masaki (Doshisha University)\nCurrent fusion plasma research requires a high intensity neutral beam of either hydrogen or deuterium to heat the plasma. The intensity of the negative hydrogen ($ {\\rm H^{-}}$) ion current extracted from an ion source chamber depends on both the plasma electrode (PE) surface material and the bias voltage agai nst the plasma potential. The amount of the negative deuterium (${\\rm D^{ -}}$) ions should exhibit similar dependence for these factors\, but with some difference due to the larger mass.\n\nIn this study\, hydrogen and de uterium plasmas are produced in a cylindrical ion source with 150 mm diame ter and 200 mm height. The cylindrical wall is surrounded with 16 rows of plasma confinement magnets. Tungsten and tantalum cathode filaments of 0.5 mm diameter produce the DC discharge plasma and evaporate the vapor to de posit the materials onto the PE surface. An extraction electrode and a Far aday cup are biased at 800 V against the ion source chamber anode. A Langm uir probe located near the PE detects plasma current out of which electron temperature and electron density are determined in the vicinity of the ex tractor. A DC laser photodetachment coupled to extraction current signal m easurement yields information on ${\\rm H^{-}}$ and ${\\rm D^{-}}$ transpo rt.\n\nhttps://indico.inp.nsk.su/event/11/contributions/297/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/297/ END:VEVENT BEGIN:VEVENT SUMMARY:First Beam Extraction Experiments at BATMAN Upgrade DTSTART;VALUE=DATE-TIME:20180904T064000Z DTEND;VALUE=DATE-TIME:20180904T070500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-298@indico.inp.nsk.su DESCRIPTION:Speakers: Werner Kraus (Max-Planck-Institut für Plasmaphysik) \nOn the BATMAN testbed prototypes of RF driven negative ion sources of ab out one eight of the size of the ITER source have been developed and teste d since 1997. The positive results had led to the decision to equip the IT ER NBI with RF sources. \nDuring the past 1.5 years this test facility has been upgraded in order to have an extraction system and source design clo ser to that of the ITER source and to improve the beam as well as the sour ce diagnostics. \nIn the new extraction system 70 apertures of 14 mm diame ter are arranged similar like in one segment of the ITER NBI. The total ex traction area was enlarged from 70 cm2 to 108 cm2 and the maximum beam ene rgy from 33 kV to 50 kV. An additional feature is the implementation of a fourth electrode upstream of the grounded grid. By this “repeller electr ode”\, which is on positive potential\, the current of the back streamin g positive ions can be reduced. In this way the space charge compensation of the beam downstream the grounded grid is expected to be changed.\nThe f ilter field\, previously generated only by permanent magnets placed at the lateral walls of the source\, can now additionally be produced\, like at the ITER source\, by a current flowing through the plasma grid which enabl es to vary the field strength.\nIn this paper the results of the first bea m extraction experiments are reported and compared to that achieved with t he previous design of the source and the extraction system with emphasis o n the impact of the improved filter field.\n\nhttps://indico.inp.nsk.su/ev ent/11/contributions/298/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/298/ END:VEVENT BEGIN:VEVENT SUMMARY:Measurement of the negative ion beam with D-Pace OWS-30 wire scann er DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-299@indico.inp.nsk.su DESCRIPTION:Speakers: Timofey Bykov (Budker Institute of Nuclear Physics)\ nA source of epithermal neutrons based on vacuum-insulated tandem accelera tor and a lithium target was proposed and developed for the technique of b oron neutron capture therapy. A stationary proton beam of 2 MeV with a cur rent of up to 6 mA was obtained in the accelerator. To optimize the inject ion of a beam of negative hydrogen ions into the accelerator\, a wire scan ner OWS-30 (D-Pace\, Canada) was installed. \nThe main problem is that usi ng the profilometer in the form in which it is provided does not allow us to determine the main beam parameters such as position and size. Also\, th e electron emission does not allow to measure the total beam current and m ay lead to incorrect measurement of the beam profile. We have modernized t he scanner by placing the metal rings in front and behind the scanner with a negative potential to suppress the secondary emission of electrons from the scanner wires. We have developed a software in which methods for calc ulating the position and size of the beam\, methods for calculating the to tal current are implemented.\nModernization of the scanner has made it pos sible to expand its capabilities. The suppression of the secondary electro n emission made it possible to reconstruct the current profile of the ion beam and determine the value of the total current. The developed program a llowed to display the coordinates of the beam\, its dimensions and the tot al current. We are the first who proposed and implemented a new way of mea surement of the beam emittance. A movable diaphragm was inserted in front of the wire scanner. Ion beam passing through the aperture of the diaphrag m was measured with а high quality detalization when the diaphragm was mo ved along one radius. The use of a modernized scanner made it possible to detect the effect of space charge and the effect of spherical aberration o f focusing magnetic lenses on a beam of negative hydrogen ions. The use of the modernized scanner made it possible to optimize the injection of a be am of negative hydrogen ions into the accelerator\, which led to an increa sing in the proton current and an improvement of the accelerator stability . The modernized scanner with an additional program for processing the res ults data and visualization has become a reliable device for beam diagnosi ng and for controlling its entry into the accelerator.\n\nhttps://indico.i np.nsk.su/event/11/contributions/299/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/299/ END:VEVENT BEGIN:VEVENT SUMMARY:Secondary Electrons Problem Study for Beam Energy Recovery for Fus ion: Experimental apparatus DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-300@indico.inp.nsk.su DESCRIPTION:Speakers: Vincenzo Variale (INFN-Bari)\nIn the ITER fusion pro ject two deuterium Neutral Beam (NB) injectors of 40 MW will be used to fu rther heating the TOKAMAK plasma up to the ignition temperature. The neutr alization method of the two D- beams\, the gas cells\, has an efficiency o f about 60%\, then residual charged beams of about 40% have to be deflecte d and dumped before the injection in the plasma. In order to improve the e lectrical efficiency of the NB production\, a beam recovery system of the residual charged particles can be studied. Since a scaled ITER type negati ve ion source\, NIO1 (Negative Ion Optimization 1)\, has been developed at RFX (Padua) in collaboration with INFN-LNL for studying and improving the ion extraction efficiency of the future NB an experimental test on beam e nergy recovery of the NIO1 beam has been recently proposed. One important issue related to the beam energy recovery and mostly to the beam dumping a re the secondary electrons generated by the interaction of the ions with t he collector walls. They may escape from the collector electrodes causing damages and\, at least\, reduce energy recovery efficiency. A Proposal of an experimental test on the secondary electrons production in the beam ene rgy recovery has been done to study that problem. In this contribution\, t he experimental apparatus set up for the test along with the simulations o f the measurements are presented and discussed.\n\nhttps://indico.inp.nsk. su/event/11/contributions/300/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/300/ END:VEVENT BEGIN:VEVENT SUMMARY:H-minus ion source emittance measuring device DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-301@indico.inp.nsk.su DESCRIPTION:Speakers: Viktor Klenov (Institute for Nuclear Research of the Russian Academy of Sciences)\nThe "pepper-pot" emittance measuring device developed earlier for INR RAS 400 keV H-minus LEBT channel was applied wi th minor modification to control the transverse emittances at the exit of H-minus ion source for 7…15 keV beam energy. It includes the "pepper- pot" mask\, the quartz screen\, the CCD camera\, PC\, the software for cam era data processing and beam phase portrait formation. The issues of obtai ning sufficient signal level at such low ions energy\, methods of subtract ing the signal of non-ion-beam illumination of quartz screen from the full amplitude of the signal as well as issues of data processing and presenta tion of phase portraits are discussed.\n\nhttps://indico.inp.nsk.su/event/ 11/contributions/301/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/301/ END:VEVENT BEGIN:VEVENT SUMMARY:The NIO1 negative ion source: investigation and operation experien ce DTSTART;VALUE=DATE-TIME:20180904T074000Z DTEND;VALUE=DATE-TIME:20180904T081000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-302@indico.inp.nsk.su DESCRIPTION:Speakers: Marco Cavenago (INFN-LNL)\nThe ion source NIO1 (Nega tive Ion Optimization 1) is a versatile multiaperture H$^-$ source capable of continuous regime operation\, with the plasma generated by a 2 MHz/2.5 kW radiofrequency (rf) power supply and nine beamlet extraction\, operate d since 2014 in close collaboration between Consorzio RFX and INFN-LNL. It aims to partly reproduce the conditions of the much larger ion sources bu ilt or in construction for neutral beam injectors of fusion devices in a c ompact and modular ion source\, where effects of individual source compone nts can be rapidly verified and compared to simulation code results. \nDue to the need of assessing negative ion production limits (especially witho ut cesiation) in continuous operation for the perspective of future fusion reactors and to the large importance of magnetic field for source optimiz ation\, several configuration changes were tried (both inside the ion sour ce and for the embedded magnets inside the accelerator grids) were investi gated\, with material ranging from hard ferrite to SmCo to NdFeB\; evidenc e of the effect of the accelerator fringe field inside the ion source is d iscussed here and in companion presentations.\nThe radiofrequency system t akes full advantage of the frequency tuning amplifier capability (+/-150 k Hz installed\, 0/+20 kHz used)\, and it is worth noting that no adjustment of matching box capacitors was necessary in the last 3 years.\nMajor diag nostic systems (including CCD cameras and BES measurement) have been integ rated with the acquisition system along with the date measured by several power supplies (including the high voltage supplies\, the rf generator and bias supplies\, the pressure measurements and the beam currents).\n\nhttp s://indico.inp.nsk.su/event/11/contributions/302/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/302/ END:VEVENT BEGIN:VEVENT SUMMARY:Theoretical models of collisional transport in negative ion source sheath DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-303@indico.inp.nsk.su DESCRIPTION:Speakers: Marco Cavenago (INFN-LNL)\nThe complexity of the neg ative ion sheath is immediately evident\, for several reasons:\nthe electr ons are magnetized\, so that a collisionless model is clearly faulty and o veroptimistic\, since it neglect electron extraction (an undesired effect) . As in other sheath models\, the kinetic effects are important\, so that the self-consistent electric potential is naturally determined by an integ ral equation. Even if numerical model to the state of arts allows to treat important 2D and perhaps 3D effects\, they are inconsistent with the actu al size of the Debye length: reliability of modified vacuum permittivity $ \\epsilon_0$ models is often invoked in the literature\; moreover\, large programming effort is needed for parallelization and months are a typical run time. On the other hand theoretical model is limited to 1D variation o f the electric potential $\\phi(z)$ with $z$ the extraction axis\, and of the magnetic field $B_x(z)$\; nevertheless it worthile to develop because it can give insight on the critical physics to possibly verify in simulati on and on the design parameters. In this paper we complete the investigati on on the singular effects of the Coulomb collision and discuss representa tion of wall collision\, in kinetic and fluid models\; for typical source parameters\, the electron-neutral collisions (included in the theoretical model) result not much larger than the former\, so motivating this analysi s. From practical point\, the need of a comparatively larger extraction vo ltage (with respect to the unmagnetized case for H$^-$ only) affecting sou rce bias current is emerging.\n\nhttps://indico.inp.nsk.su/event/11/contri butions/303/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/303/ END:VEVENT BEGIN:VEVENT SUMMARY:Ultracold Muonium Negative Ion Production DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-304@indico.inp.nsk.su DESCRIPTION:Speakers: Vadim Dudnikov (Muons\, Inc)\nA new\, efficient meth od to produce ultracold negative muon ions is proposed. The muonium atom i s made up of an anti muon and an electron and is given the chemical symbol Mu. A second electron with binding energy or electron affinity of 0.75 eV makes the Mu- ion\, which is in many ways almost identical to the H- ion that is used for charge-exchange injection into most proton particle accel erators. Muonium negative ions were observed in 1987 [ \, ] by interaction of muons with a foil. Using the foil charge-exchange approach\, the effic iency of transformation of muons to negative muonium ions has been very lo w ~10-4. However\, by using a hot tungsten or palladium single crystal foi l treated by cesium deposition\, the production efficiency can be improved up to 50%. The process described here has surface muons focused onto a tu ngsten or palladium single crystal foil (that can be heated up to 2000 Cel sius) and partially covered by a cesium layer up to minimal work function. The negative muon ions can be extracted by a DC electric field and furthe r accelerated by a linac and stripped in a thin foil.\n\nhttps://indico.in p.nsk.su/event/11/contributions/304/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/304/ END:VEVENT BEGIN:VEVENT SUMMARY:Performance of Radio frequency plasma generator for neutral beam i njector DTSTART;VALUE=DATE-TIME:20180907T023000Z DTEND;VALUE=DATE-TIME:20180907T025500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-305@indico.inp.nsk.su DESCRIPTION:Speakers: Yahong xie (Institute of Plasma Physics\, Chinese Ac ademy of Sciences)\nThe China Fusion Engineering Test Reactor (CFETR) is a next generation fusion device towards the using of fusion energy. The mai n machine of CFETR and the auxiliary plasma heating tools including the Ne utral beam injector (NBI) were under design. The high power ion source is the most precision and important part of NBI. \nA negative ion source was designed for the key technology study and performance tests of hgih power ion source. The plasma generator contains a RF driver and a expansion cha mber. The diameter of driver is 20 cm and the height is 15cm. Six turns of external coils was used for the plasma generation. A matching unit was de sign to transfer the RF power (100kW @ 1MHz) to the coils. Several diagnos tic tools were used for the plasma parameters measurement.\nThe RF plalsma generator was tested with high density plasma generation and long pulse o peration. The details of experimental results will be presented in this pa per.\n\nhttps://indico.inp.nsk.su/event/11/contributions/305/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/305/ END:VEVENT BEGIN:VEVENT SUMMARY:Observation of low frequency oscillation in a filament-arc-based n egative ion source DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-306@indico.inp.nsk.su DESCRIPTION:Speakers: Kenichi Nagaoka (National Institute for Fusion Scien ce)\nDevelopment of high-density negative ion plasmas and control of behav iors of the negative ion plasmas and beams are performed for a variety of application of negative ion beams. Three negative ion beam injectors based on filament-arc source have been operational for plasma experiment in Lar ge Helical Device. In order to improve the negative ion beam performance i n deuterium beam operation\, further investigation of particle dynamics an d beam characteristics in the negative ion source are experimentally perfo rmed in NIFS-NBTS. \n\nRecently\, an oscillation with the frequency of sev eral hundred Hz was observed in the plasma. The oscillation seems to be dr iven by a power supply for biasing plasma grid\, and should be suppressed for working injector. In this study\, however\, the oscillation is useful to investigate the dynamic response of the beam to the plasma in the vicin ity of the plasma grid. \n\nIn the symposium\, the observed oscillation of the plasma will be presented\, and the response of the beam characteristi cs will be discussed.\n\nhttps://indico.inp.nsk.su/event/11/contributions/ 306/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/306/ END:VEVENT BEGIN:VEVENT SUMMARY:Evaluation of the temperature dependance of the Cesium deposition on the plasma grid in the JT-60 negative ion source DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-307@indico.inp.nsk.su DESCRIPTION:Speakers: Masafumi Yoshida (Yamaguchi University)\nModeling fo r a longer stable production of the negative ion beams in the JT-60 negati ve ion source is constructed\, based on the experimentally obtained temper ature dependace of the cesium (Cs) adsorption/desorption. In this model\, a thickness of the Cs layer on a plasma grid (PG) in this source is evaul ated\, because the Cs layer loweres a work function of the PG to enhance t he negative ion production. By using this model\, slight degradation of th e negative ion beams for a 100 s pulse operation in this source is underst ood. As a result\, it is found that the thickness is deterimed by a balanc e of the adsorbed/desorbed amounts of Cs in the PG and a chamber wall and of the introduced/evacuated one. In addition\, it is suggested that the o rigin of the degradation of the beams is an excessive depostion of the Cs on the PG\, due to rising the temprature of the chamber wall and increasin g the desorbed Cs from it. For suppression of the degradation and longer s table production of the negative ion beam\, temperature dependance of the thickness of the Cs layer on the PG is examined by changing temperatures o f the PG\, chamber wall and Cs oven\, and combination of the optimal tempr ature at them is preliminary proposed.\n\nhttps://indico.inp.nsk.su/event/ 11/contributions/307/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/307/ END:VEVENT BEGIN:VEVENT SUMMARY:Negative ion and helicon wave physics on the Resonant Antenna Ion Device (RAID) DTSTART;VALUE=DATE-TIME:20180905T070000Z DTEND;VALUE=DATE-TIME:20180905T072500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-308@indico.inp.nsk.su DESCRIPTION:Speakers: Riccardo Agnello (Ecole Polytechnique Federale de La usanne)\nThe Neutral Beam Injector (NBI) system for DEMO is designed to de liver a beam with energy 800 keV\, accelerated current 34 A\, and will req uire a neutralization efficiency for negative ions larger than 70\\% [1]. Research groups in France and Switzerland are developing a new source conc ept for DEMO NBI based on a magnetized plasma column produced by a helicon antenna [2]. In RAID (Resonant Antenna Ion Device) at the Swiss Plasma Ce nter\, the physics of volume-produced negative ions and helicon plasmas is investigated. RAID is a linear device producing steady state plasma disch arges with different gases\, including $H_2$ and $D_2$\, by means of a res onant helicon antenna with RF power up to 10 kW [3-4]. Previous optical em ission spectroscopy (OES) data reveal a significant volume production of $ H^-$ and $D^-$ and a favorable scaling law with power [5]. To confirm the previous results with a totally independent technique for detecting negat ive ions\, Cavity Ring-Down Spectroscopy (CRDS) was recently installed. We present first CRDS measurements which provide values in agreement with OE S\, confirming that negative ions are produced in the RAID plasma column w ith significant densities.\nRAID is also devoted to the study of helicon w ave physics and\, in particular\, of the mechanisms that lead to the produ ction of a steady state plasma discharge. Many physics issues on helicon p lasma sources are still open regarding\, for instance\, how the power is d eposited in the plasma. We present three-dimensional plasma density and te mperature profiles measured by means of a two-axis Langmuir probe and cali brated with a 100 GHz microwave interferometer. These reveal the productio n of a radially peaked density and temperature plasma column with good hom ogeneity in the axial direction for up to one meter. This last property co uld be favorable for the homogeneity of negative ion production. Moreover\ , magnetic probe measurements are used to reconstruct the propagation of h elicon waves for comparison with COMSOL simulations\, with the aim of link ing together different plasma regimes and negative ion production.\n\n\n[1 ] P. Sonato et al. “Conceptual design of the beam source for the DEMO N eutral Beam Injectors” New J. Phys. (2016) 18 125002\n \n[2] A. Simonin et al. “Negative ion source development for a photoneutralization based neutral beam system for future fusion reactors” New J. Phys. 18 (2016) 1 25005\n\n[3] Ph. Guittienne et al. “Towards an optimal antenna for helic on excitation”\, J. Appl. Phys. 98\, 083304 (2005)\n\n[4] I. Furno et al . “Helicon wave-generated plasmas for negative ion beams for fusion”\, EPJ Web of Conferences 157\, 03014 (2017) \n\n[5] C. Marini et al. “Spe ctroscopic characterization of H_2 and D_2 helicon plasmas generated by a resonant antenna for neutral beam application in fusion”\, Nucl. Fusion 57 (2017) 036024\n\nhttps://indico.inp.nsk.su/event/11/contributions/308/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/308/ END:VEVENT BEGIN:VEVENT SUMMARY:Experimental study of electrostatic residual ion dump DTSTART;VALUE=DATE-TIME:20180906T063000Z DTEND;VALUE=DATE-TIME:20180906T065500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-309@indico.inp.nsk.su DESCRIPTION:Speakers: Alexander Panasenkov (NRC "Kurchatov Institute")\nRe ference design of the Residual Ion Dump (RID) for the ITER NBI system is b ased on an electrostatic deflection of the residual negative and positive ions to in-line dump panels. According to 4-channels beam line concept\, R ID forms four narrow (about 100 mm in width) vertical channels with the ai d of 5 panels (1.8 m long and 1.7 m in height). Two middle panels are nega tively biased with about 20 kV. This concept has the advantage of compact design with quite moderate power density (PD) load onto the panels – pea k PD is less 8 MW/m2.\nHowever\, such a concept has never been earlier tes ted in any operating NBI system\, all of them used magnetic deflection sys tems with remote ion dumps. \nThis report describes experimental investiga tion of the electrostatic RID concept which was carried out at the test st and IREK at the Kurchatov Institute.\nThe main physical questions were:\n- Effect of the ion beam space charge on the RID deflection properties.\n- Secondary electrons production and their behaviour in the crossed electric and magnetic fields\, which can have an influence on the high voltage hol ding and state of operability. \n Tested RID was designed with followin g conditions:\n- Mono-atomic and mono-energetic positive helium ion beam w ith energy up to 50 keV instead of hydrogen beam with complex composition. \n- One RID channel consisting of two panels 1x1 m and 150 mm in width\, o ne panel is under negative potential up to 12 kV.\n- Special magnetic syst em (MS) which produces rather uniform vertical magnetic field in the RID v olume to simulate the ITER NBL conditions. Moreover\, the MS was designed to produce Bz up to 130 Gs to compare electrostatic and magnetic deflectio n. \n Experimental results showed that:\n- The space charge of the beam with current at a level of 4÷5 A influences significantly on the require d deflecting voltage – it was necessary to increase it about twice in co mpare with calculated without space charge.\n- Secondary plasma gives also noticeable effect on the increase of the deflecting voltage.\n- Drift of secondary electrons in crossed ExB fields does not influence noticeably on the high voltage holding.\n The modeling program was developed which d escribed the electric field distribution in the RID volume with account of the beam space charge and calculated trajectories of the deflected ions. The results of calculations were in good agreement with the experimental o ne. So\, this program was used for calculation of the mixed beam of positi ve and negative deuterium ions (about 2 A each per one channel) deflection in the ITER RID. It was shown that 1 MeV ion current densities are small enough and moreover at the initial part of the RID channel positive and ne gative beams compensate space charge of each other. So\, deflecting voltag e of 20÷25 V will be enough for stable RID operation.\n\nhttps://indico.i np.nsk.su/event/11/contributions/309/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/309/ END:VEVENT BEGIN:VEVENT SUMMARY:Effects of impurity ions upon Cs recycling in a negative hydrogen ion source DTSTART;VALUE=DATE-TIME:20180903T071000Z DTEND;VALUE=DATE-TIME:20180903T073500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-310@indico.inp.nsk.su DESCRIPTION:Speakers: Motoi Wada (Doshisha University)\nPlasma surface int eraction in a cesiated negative hydrogen (H$^-$) ion source determines the overall Cs consumption rate of the source. The Cs coverage on the plasma grid (PG) surface is reduced mainly by two mechanisms. The first mechani sm is the removal of Cs from the PG by direct sputtering\, or ion induced desorption. The second is the deposition of atoms that form a layer above the Cs covered low work function PG surface. The first mechanism associa ted with incoming ions removes some part of the loosely bound atoms on the surface to reduce the deposition rate. The second process also affects t he first\, because the PG surface contaminated with deposited atoms should result a Cs removal rate different from the original value of the conditi on with the half monolayer of Cs on top of the pure PG material.\n\nRemova l rates of Cs atoms on PGs have been estimated using a collision cascade s imulation code ACAT (Atomic Collisions in Amorphous Target). The code has predicted the enhanced removal of Cs by the interlayer of medium mass num ber elements between the bulk PG material and the Cs top layer. The simul ation has to employ several assumptions that are too ideal as the PG surfa ce condition of an actual ion source\; the simulation does not take impuri ty effects into account. This paper attempts to study the contribution of the second process to the Cs recycling\; how the incoming atoms and ions including those produced and transported in plasma modify the surface cond ition and change the Cs coverage on the PG. Lessons from tungsten filamen t driven arc discharge sources are compared with the simulation results\, and the expected performance including Cs recycling of a RF H$^-$ source i s discussed.\n\nhttps://indico.inp.nsk.su/event/11/contributions/310/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/310/ END:VEVENT BEGIN:VEVENT SUMMARY:Characterization of the helicon plasma generated inside the Cybele negative ion source with different magnetic field configurations DTSTART;VALUE=DATE-TIME:20180905T073000Z DTEND;VALUE=DATE-TIME:20180905T075500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-311@indico.inp.nsk.su DESCRIPTION:Speakers: Iaroslav Morgal (CEA Cadarache\, IRFM / Aix-Marseill e Universite)\nThe Cybele negative ion source is designed and operated at the IRFM in CEA Cadarache for the development of the future NBI system SIP HORE for future fusion reactors [1]. The main objective is to create a thi n and tall (blade-like) negative ion beam (H-\,D-)\, which will be neutral ized by the laser photodetachment. For this purpose Cybele has an aspect r atio (1.2 m high *0.15 m wide) which is directed to the creation of a dens e and homogeneous magnetized plasma column in order to produce and extract negative ions on the side edge along the main axis.\n\nIn 2011\, IRFM sta rted a collaboration with EPFL Lausanne for the development of a bird-cage type Helicon antenna on the RAID testbed dedicated to the Cybele source. The RAID testbed is equipped with a set of coils (40cm diameter) outside t he vacuum chamber to generate an axial magnetic field. The helicon plasma column obtained on RAID exhibits very promising characteristics [2] for it s application on Cybele. It is an ideal configuration for the propagation of the helicon waves in the plasma but this closed magnetic confinement is not suitable for the implantation on the plasma edge of extraction and ac celeration systems. \n\nIn 2017 a similar Helicon antenna was installed in the top of the Cybele source to study the negative ion extraction from th e helicon magnetized plasma column.\nFor this purpose\, the first step of this study is focused on the exploration of different magnetic confinement of the plasma column which should be compatible both with the propagation of the helicon waves in the Cybele plasma column and the beam extraction. \nTwo magnetic field configurations are under investigation: the first on e is based on two lateral coils sitting on opposite sides of an iron recta ngular frame which surrounds the source\; the second one is based on a set of 11 coils implemented within the source volume under vacuum. Plasma dia gnostics by Langmuir probes allow the characterize the plasma parameters u nder these two different configurations. The experimental results and the comparison between these two configurations will be presented.\n\nhttps:// indico.inp.nsk.su/event/11/contributions/311/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/311/ END:VEVENT BEGIN:VEVENT SUMMARY:High brightness H- ion source for accelerators developed at TRIUMF DTSTART;VALUE=DATE-TIME:20180905T040000Z DTEND;VALUE=DATE-TIME:20180905T042500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-312@indico.inp.nsk.su DESCRIPTION:Speakers: Keerthi Jayamanna (TRIUMF)\nTRIUMF has developed H- ion sources for decades and now they are being employed in machines such a s the 500MeV\, TR30\, TR13 at TRIUMF as well as various other machines wor ldwide. A high current version can produce up to 60 mA of H- beam. A new H - ion source with a small plasma volume is being developed to produce 5 mA at a very low emittance and run years without changing the filament. Due to the low cost\, low emittance and educed maintenance needs\, this ion so urce will suit cyclotrons as well as other accelerators looking for reliab le\, stable operation over long time. Having four extraction electrodes\, this ion source can run at optimum extraction voltage while delivering bea m energies from 1kV to 60kV with little or no degradation to the beam qual ity. Performance of the source including beam current\, arc parameters\, e mittance and filament life time are discussed in this paper. The source pa rameters effecting emittance are discussed in details.\n\nhttps://indico.i np.nsk.su/event/11/contributions/312/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/312/ END:VEVENT BEGIN:VEVENT SUMMARY:Research and development of power feed-in system for RF negative i on source on ASIPP DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-313@indico.inp.nsk.su DESCRIPTION:Speakers: Caichao Jiang (Institute of Plasma Physics\, Chinese Academy of Sciences)\nA negative ion source test facility was developed f or the ion source performance tests. In order to support the experimental research\, a power feed-in system was designed\, which contains a solid st ate radio frequency (RF) generator and a matching network of L type with h igh voltage transformer. The design of RF generator was presented in this paper according to the requirements and characteristics of plasma discharg e of RF ion source. Combine with the impedance characteristics of plasma d ischarge of RF ion source\, the matching network was designed with high vo ltage transformer\, including the calculation and simulation of main param eters of each parts of matching network. The characteristic of RF power ma tching was studied to gets high efficiency power transferred into the RF i on source. It can generate stable plasma with high power and long pulse du ration.\n\nhttps://indico.inp.nsk.su/event/11/contributions/313/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/313/ END:VEVENT BEGIN:VEVENT SUMMARY:Design of Negative Ion Source Using a Plasma Electrode of C12A7 E lectride DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-314@indico.inp.nsk.su DESCRIPTION:Speakers: Masumi Kobayashi (Doshisha University)\nAlkali metal such as cesium covers the plasma electrode to enhance the negative hydrog en ion surface production in a negative ion source. Accumulation of Cs in the source shortens the maintenance cycle of the apparatus. In this resear ch\, inorganic material\, C12A7 electride\, which has low work function an d high electric conductance\, is studied as a candidate material for a new type of cesium-free plasma electrode.\nOne of the key issues of this type of ion source design is in-situ baking mechanism and the temperature cont rol system of the plasma electrode made of C12A7 electride. Figure 1 shows the result of the ohmic heating test of electride\; i.e.\, direct electri cal current was induced to the sample. The value of conductivity increases with increasing temperature. The sample heating up to $328.5\\ {}^\\circ\ \mathrm{C}$ caused non-uniform temperature distribution\, and the material became fragile. Another key issue is removal of impurity layer formed on the electride.\nWe design a negative ion source having an ECR plasma sourc e and a three electrode extractor: acceleration and deceleration grids\, w ith the electride plasma grid having an indirectly heating system. The pre liminary results on the characteristics measurements of the ion source wil l be presented.\n\n\n [1]: http://35.202.118.59/wp-content/uploads/2018/0 5/NIBS.jpg\n\nhttps://indico.inp.nsk.su/event/11/contributions/314/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/314/ END:VEVENT BEGIN:VEVENT SUMMARY:NIBS 2020 Presentation DTSTART;VALUE=DATE-TIME:20180907T070000Z DTEND;VALUE=DATE-TIME:20180907T072000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-315@indico.inp.nsk.su DESCRIPTION:Speakers: Morgan Dehnel (D-PACE Inc)\nhttps://indico.inp.nsk.s u/event/11/contributions/315/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/315/ END:VEVENT BEGIN:VEVENT SUMMARY:Analysis of Plasma Impedance in the Linac4 H- Source DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-316@indico.inp.nsk.su DESCRIPTION:Speakers: Wakaba Kobayashi (Keio University)\nA new linear acc elerator Linac4 [1] is being commissioned at CERN as a part of the upgrade of their accelerator chain. A radio frequency (RF) driven type negative h ydrogen H- source is used as an injector of Linac4. The Linac4 H- source m ust deliver 40-50 mA\, 45 keV H- beam. The power transfer efficiency betwe en the RF generator and the ion source plasma is one of the important para meters that determine the extracted H- beam current. In order to achieve e fficient power supply\, it is required to match the impedance between the RF system and plasma loading. In order to match the impedance\, it is esse ntial to analyze the plasma impedance. \n\nIn this study\, we analyze the plasma impedance by using the numerical simulation code[2]. The model con sists mainly two parts. One is the two-dimensional model of RF electromagn etic field\, which calculates the electromagnetic fields numerically by so lving Maxwell equations using the Finite Difference Time Domain (FDTD) Met hod. The other part is the particle dynamics model with the three-dimensio n in real and velocity space. The equations of motion for the charged part icles are numerically solved. The particle velocity is also changed by col lision process which is modeled by Monte Carlo method. \n\nWe are now anal yzing the plasma resistance and inductance under the steady state. As the first step\, the absorbed power to plasma is calculated by using Poynting theorem. The next step\, the plasma resistance and inductance are modeled from the absorbed power to plasma. Also\, we have developed the impedance prediction model which is the theoretical model [3] assuming Maxwellian di stribution. The comparison between the results of the numerical simulation and those of the theoretical model will be presented. \n\n[1] J. Lettry\, D. Aguglia\, Y. Coutron\, E. Chaudet\, A. Dallocchio\, et al.\, AIP Conf. Proc. 1515\, 302–311 (2013) \n\n[2] S. Mattei\, K.Nishid\, M.Onai\, J. Lettry\, M.Q.Tran and A.Hatayamac\, J. Comput. Phys. 350\, 891–906 (2017 ) \n\n[3] Pascal Chabert and Nicholas Braithwaite\, “Physics of Radio-Fr equency Plasmas”\, Cambridge University Press\, New York\, (2011).\n\nht tps://indico.inp.nsk.su/event/11/contributions/316/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/316/ END:VEVENT BEGIN:VEVENT SUMMARY:The Particle Tracking Code BBCNI for Negative Ion Beams and its Ap plication to BATMAN Upgrade DTSTART;VALUE=DATE-TIME:20180906T023000Z DTEND;VALUE=DATE-TIME:20180906T025500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-317@indico.inp.nsk.su DESCRIPTION:Speakers: Andrew Hurlbatt (Max-Planck-Institut für Plasmaphys ik)\nFor the continued improvement and development of large negative hydro gen ion sources for NBI applications\, beam characterisation is of critica l importance for understanding and predicting the interaction of the beam with\, for example\, a gas neutraliser system. The relationship between th e results of beam diagnostics and the physical properties of the beam is n ot a trivial one\, and a full understanding of the data requires the suppo rt of a simulation.\n\nThis simulation should be fully 3D\, in order to en compass the complex electric and magnetic fields\, and needs to provide si mulated diagnostics that recreate what is present in the experiment. A PIC simulation is unsuitable due to the very large size of the domain\, but i nformation at the particle level is still required\, as no assumptions abo ut velocity or spatial distributions can be made. Thus a particle tracking code is required\; one that calculates the trajectories of particles thro ugh pre-supplied electric and magnetic fields.\n\nThe code BBCNI [1] has b een designed to fulfil these requirements\, and is presented here after si gnificant upgrades and improvements. In the code\, particles are accelerat ed from the plasma side of the extraction grids of the system being modell ed\, and their trajectories are calculated to the calorimeter with a fully relativistic treatment. Along these trajectories\, particles can interact with the background gas to undergo reactions and emit photons. Particles hitting any physical object are recorded\, allowing the reconstruction of the heat loads on beam line components and the calorimeter. Diagnostic pla nes can be inserted into the simulation domain to record particle properti es at any location in space. Generated photons are recorded\, and post-pro cessed to generate spectra simulating the diagnostic results of a Beam Emi ssion Spectroscopy (BES) system. Full traceability of these spectra allow specific features to be linked to specific particle populations and areas of the beam\, providing a much-needed understanding of experimental result s. While the code is currently configured to assist with the understanding of beam diagnostics on the BATMAN Upgrade and ELISE test facilities at IP P\, it is designed to be flexible\, and could in principle be applied to a ny similar ion source.\n\nIn order to demonstrate the capability of the co de\, the first experimental BES results from the BATMAN Upgrade test facil ity are also presented. Analysis and interpretation of the data in terms o f beam properties is demonstrated. A comparison between the experimental s pectra and those generated by BBCNI is shown\, and the similarities and di fferences are discussed.\n\n[1] B. Ruf\, P. Franzen and U. Fantz\, Investi gation on the beam homogeneity in large sources for negative hydrogen ions \, 40th EPS Conference on Plasma Physics\, 2013\n\nhttps://indico.inp.nsk. su/event/11/contributions/317/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/317/ END:VEVENT BEGIN:VEVENT SUMMARY:Negative Ion and Neutral Beams Injectors at the Budker Institute o f Nuclear Physics DTSTART;VALUE=DATE-TIME:20180903T024000Z DTEND;VALUE=DATE-TIME:20180903T030500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-318@indico.inp.nsk.su DESCRIPTION:Speakers: Alexander Ivanov (Budker Institute of Nuclear Physic s)\nAn overview of the negative ion and neutral beam injectors\, developed at the Budker Institute of Nuclear Physics is presented. The highlights a nd innovations\, used in a variety of positive and negative ion sources\, produced by BINP team for plasma heating\, diagnostics and for injection i nto accelerators are discussed. Data and long-term experience of BINP prod uced ion sources service at the fusion experimental devices and accelerato rs are described.\n\nhttps://indico.inp.nsk.su/event/11/contributions/318/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/318/ END:VEVENT BEGIN:VEVENT SUMMARY:Calorimeters for high power ion and neutral beam injectors DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-319@indico.inp.nsk.su DESCRIPTION:Speakers: Petr Deichuli (Budker Institute of Nuclear Physics)\ nThe significant part of any high-power neutral beam injector is the beam absorber\, which serves also as a calorimeter. The power neutral beam inje ctor operates in multimegawatt range and the peak-power densities normal t o the beam axis can reach few tens kW/cm2\, especially for injectors with beam focusing. With these parameters the main problem is the crisis of th e heat transfer between the inner wall of the cooling channel and the cool ing water\, which limit allowable power density at calorimeter surface by the ~5-7 kW/cm2 [1]. The operation at a high power density requires the hi gh water velocity and flow rate. In addition\, it means a complicate water -cooling system and calorimeter construction. \nIn this paper\, the calori meter based on the tubes with narrow annular cooling channels and with spi ral flow swirler described. This construction is technologically simple an d has a higher heat transfer characteristic at a moderate flow rate and ve locity in comparison with the typical design based on twisted tape in a cy lindrical cooling channel as a flow swirler. \nSimple methods of beam over lap with the location of pipes in one echelon offered. This method allow s ufficiently simplify the calorimeter design. \nThe construction designed and tested in 2008 for 1.7 MW injector. The neutral power flow density at axis was 12-15 kW/cm2. About 2 thousand pulses were made during tests\, t he systems of 6 power injectors operates with such type calorimeters [2]. \n\n1. S.K.Combs\, S.L.Milora\, C.A.Foster\, H.H.Haselton\, M.M.Menon\, C.C.Tsai. Compact inexpensive target design for steady-state heat remov al in high-heat-flux fusion applications. Rev. Sci. Instrum.\, 56\, 1526 ( 1985).\n2. A.Sorokin\, V.Belov\, V.Davydenko\, P.Deichuli\, A.Ivanov\, A.Podyminogin\, I.Shikhovtsev\, G.Shulzhenko\, N.Stupishin\, M.Tiunov. “ Characterization of 1 MW\, 40 keV\, 1 s neutral beam for plasma heating” . Rev. Sci. Instrum. 81\, 02B108 (2010)\n\nhttps://indico.inp.nsk.su/event /11/contributions/319/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/319/ END:VEVENT BEGIN:VEVENT SUMMARY:H- beam formation and electron dumping strategies DTSTART;VALUE=DATE-TIME:20180905T090000Z DTEND;VALUE=DATE-TIME:20180905T092500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-320@indico.inp.nsk.su DESCRIPTION:Speakers: Taneli Kalvas (University of Jyvaskyla\, Department of Physics)\nToday's new developments\, such as CERNs Linac4 injector\, po se strong demands on the extraction and LEBT systems. Designing such syste ms is challenging. First of all the H- ion beam formation is difficult to model: the physics taking place at the extraction sheath is rich and appro ximations have to be made. The extraction system is strongly affected by t he need for co-extracted electron separation from the ion beam using a mag netic filter at a relatively early stage to avoid adverse space charge eff ects on the ion beam\, mainly observed as increased transverse emittance. In many cases the electron beam power sets limits to the energy at which t he dumping can be performed. As a result one of the three methods is often chosen for separating the electrons: \n\n(1) dumping at the puller electr ode before acceleration to full energy\, \n\n(2) dumping at a decelerating einzel lens or \n\n(3) dumping at an intermediate low energy electrode be fore the puller electrode. \n\nThis paper discusses the H- beam formation and emittance in the light of the results from CERNs Linac4 RF-driven ion source and the TRIUMF-type filament-driven ion source and discusses the di fferent extraction and dumping strategies used in these sources.\n\nhttps: //indico.inp.nsk.su/event/11/contributions/320/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/320/ END:VEVENT BEGIN:VEVENT SUMMARY:Graphical representations of spectral data of negative ions DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-321@indico.inp.nsk.su DESCRIPTION:Speakers: Vladislav Kazakov (Novosibirsk State University\, Ru ssia)\nThe purpose of the work is to expand the electronic database "Elect ronic structure of atoms" [1] through the information on the negative ions of various chemical elements. As far as the authors are aware\, at presen t there is no specialized database on negative ions in the scientific lite rature and Internet.\nThe collection and analysis of information on atomic systems can be documented in a tabular or graphical representation. It is convenient to have accurate and extensive data on the spectra of elements in the form of tables\, while the graphical form is good for general orie ntation in the electronic structure of atomic systems.\nIn atomic spectros copy\, a graphical form of displaying information in the form of Grotrian diagrams is generally used\, the main purpose of which is to provide a vis ual representation of the distribution of excited states of electron confi gurations and present the most intensive transitions. For neutral atoms an d positive ions\, the experimentally measured spectral lines lie at the ba se of plotting the diagrams. According to these data\, the spectral terms and configurations are theoretically calculated. In view of the unusual us e of quantum laws for negative ions\, as well as the scarcity of informati on about their spectra\, the method for constructing of Grotrian diagrams of negative ions is somewhat different. At first\, the energies of the spe ctral terms are found from the published experimental data. After that the wavelength of the spectral line is calculated from the energy difference between the two terms. As a rule\, the multiplicities of terms are indisti nguishable. \nLet’s take the chlorum (Cl) as an example. Comparing the d iagram of positive ion Cl II [1] and constructing the same for negative io n according on the data taken from [2] we can reveal significant differen ces. First of all\, resonance lines of ions belong to different spectral a reas and there is no data on the intensity of spectral lines of the negati ve ion. The tabulated values for the positive ion Cl II are presented muuc h more completely\, than that for the negative ion of this element: 274 le vels and 691 lines for Cl II\, but only single data for the negative ion.\ nThe authors expect that the systematization of experimental data on the s pectral properties of negative ions and its representation in a graphical form will be useful to physicists working with these atomic systems.\n\n\n \n[1] http://www.grotrian.nsu.ru\n\n[2] Massey H. Negative ions. 3rd edit ion. Cambridge (UK): Cambridge University Press\, 741 p.\n\nhttps://indico .inp.nsk.su/event/11/contributions/321/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/321/ END:VEVENT BEGIN:VEVENT SUMMARY:Caesiated H- source operation with helium DTSTART;VALUE=DATE-TIME:20180903T051000Z DTEND;VALUE=DATE-TIME:20180903T053500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-322@indico.inp.nsk.su DESCRIPTION:Speakers: Katsuyoshi Tsumori (National Institute for Fusion Sc ience)\nThe consumption rate of caesium (Cs) for negative hydrogen (H-) io n source increases when the source operation gas is changed from hydrogen to deuterium. A clear indication that a deuterium discharge erodes Cs ato ms on the surface to increase work function\, and thus\, co-extracted elec tron current. We have proposed a model that the enhanced sputtering yield of Cs from the plasma grid (PG) due to deuterium ions\, which carries mor e kinetic energy to Cs adsorbed on the surface directly or indirectly\, is the main reason for this fast dissipation of Cs.\nIntroduction of helium (He) into discharge can verify the enhanced sputtering effect due to heavi er ions in ion source discharge. Comparing the effect due to seeded Cs be fore and after the He injection into discharge through Cs OES signals as w ell as the H- density measured with cavity ring-down method\, the sputteri ng/evaporation enhancement due to He is estimated. Neutral atoms and posi tive ions in the He discharge should cause enhanced sputtering like deuter ium\, while the system does not generate neutron under the induction of ac celeration voltage to diagnose the extracted negative ion beam. Plasma pa rameters of the H2 and He plasmas will be investigated by diagnostics tool s installed on NIFS-RNIS (National Institute for Fusion Science\, Research and development Negative Ion Source) together with cavity ring down. Enh anced consumption rate of Cs will be compared with proposed sputtering yie ld data to predict the rate for deuterium operation of negative ion source s.\n\nhttps://indico.inp.nsk.su/event/11/contributions/322/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/322/ END:VEVENT BEGIN:VEVENT SUMMARY:Thermal characterization of the SPIDER diagnostic calorimeter DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-323@indico.inp.nsk.su DESCRIPTION:Speakers: Antonio Pimazzoni (Consorzio RFX)\nIn order to verif y the accomplishment of the ITER requirements regarding the maximum allowe d beam non-uniformity (below ±10%)\, beamlet divergence and stripping los ses during short pulse operation (several seconds)\, a diagnostic calorime ter\, named STRIKE [1]\, will be exposed to the negative hydrogen ion beam of the ITER ion source prototype SPIDER [2]. The facility\, located at Co nsorrzio RFX (Padova\, Italy) has started the experimental activities in 2 018 at Consorzio RFX (Padova\, Italy). \nThe STRIKE sensor is constituted by 16 unidirectional carbon fiber-carbon matrix (CFC) composite tiles (376 mm × 142 mm × 20 mm)\, arranged in a 4 × 4 matrix\, resembling the arr angement of the SPIDER beamlet groups. By exposing the tiles to the beam a nd recording their temperature with infra-red cameras the beam energy flux can be retrieved by calorimetry.\nThe requirements of the 1D CFC material include a large thermal conductivity along the tile thickness (one order of magnitude larger than in the other two directions)\, uniform parameters over the tile surface and the capability to withstand localised heat load s in the order of 10-20 MW/m2. \nThe realization of large CFC tiles satisf ying all of these requirements is not straightforward and tests were perfo rmed in the last years on many prototype versions from different manufactu rers. This contribution gives an overview of the tests performed to assess the thermal properties of the tiles composing the actual STRIKE\, to be i nstalled in the SPIDER vacuum vessel during 2018. The spatial uniformity o f the parameters and the ratio between the thermal conductivities are asse ssed by means of a CO2 power laser at Consorzio RFX. Non-linear thermal fi nite-element simulations are carried out and compared to the experimental data to interpret them and to estimate the thermal conductivities. \nThis work was set up with partial financial support of F4E.\n\n[1] A. Rizzol o et al.\, Fusion Eng. Des. 85\, 2268 (2010)\n[2] R.S.Hemsworth et al.\ , Rev.Sci.Instrum. 79 (2008) 02C109\n\nhttps://indico.inp.nsk.su/event/11/ contributions/323/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/323/ END:VEVENT BEGIN:VEVENT SUMMARY:High Current Results from the 2X Scaled Penning Source DTSTART;VALUE=DATE-TIME:20180904T030000Z DTEND;VALUE=DATE-TIME:20180904T032500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-324@indico.inp.nsk.su DESCRIPTION:Speakers: Dan Faircloth (STFC Rutherford Appleton Laboratory)\ nTo meet the full 2 ms 50 Hz 60 mA beam requirements for the Front End Tes t Stand (FETS) at the Rutherford Appleton Laboratory (RAL)\, a new cesiate d Penning Surface Plasma Source (SPS) has been developed with a larger pla sma volume with 2X the linear dimensions of the standard ISIS source [1]. \n\nA clean 75 mA H– beam has been measured from the 2X Scaled Source on the VESPA test stand at full 2 ms 50 Hz duty cycle. At lower 800 µs duty cycles H– beam currents of 150 mA have been measured at high discharge currents. Two different extraction geometries are studied. Emittance scans and perveance sweeps are shown.\n\n\n[1] “2X Scaled Penning Source Deve lopments”\, D. C. Faircloth\, S. R. Lawrie\, J. Sherman\, P. Wise\, M. O . Whitehead T. Wood and T. Sarmento\, Proceedings of ICIS2017\, Geneva\, 2 017.\n\nhttps://indico.inp.nsk.su/event/11/contributions/324/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/324/ END:VEVENT BEGIN:VEVENT SUMMARY:Negative Ion Beam production and Transport via the LEBT of the HV injector prototype DTSTART;VALUE=DATE-TIME:20180906T073000Z DTEND;VALUE=DATE-TIME:20180906T075500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-325@indico.inp.nsk.su DESCRIPTION:Speakers: Oleg Sotnikov (Budker Institute of Nuclear Physics)\ nHigh-voltage negative-ion based injector is under development at Budker I nstitute of Nuclear Physics. Negative ion part of the injector is studied at separate test stand and consists of: 1) the long-pulse RF surface-plasm a source\, 2) low energy beam transport line (LEBT)\, 3) single aperture 0 .5-1 MeV accelerating tube. Deflecting magnets and high speed cryopumps (1 0^5 l/s)\, that are installed in LEBT\, purify the transported negative io n beam from the co-streaming fluxes of electrons\, hydrogen atoms and mol ecules\, and cesium vapor. As a result\, the loading on the accelerating t ube by harmful co-streaming and secondary particles is considerably reduce d. It will enable more stable operation of the negative ion beam accelerat or.\nPaper presents experimental results on 1 A\, 90 keV H- beam productio n and transport through the LEBT to the multisection calorimeter\, install ed at distance 3.5 m from the source. The parameters of the transported be am were measured at distance 1.6 m by the movable Faraday cup and at the L EBT exit - by beam calorimeter. The efficiency of beam transport vs variou s source and LEBT parameters will be presented and discussed.\n\nhttps://i ndico.inp.nsk.su/event/11/contributions/325/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/325/ END:VEVENT BEGIN:VEVENT SUMMARY:Negative ion radio frequency surface plasma source with solenoidal magnetic field DTSTART;VALUE=DATE-TIME:20180907T040000Z DTEND;VALUE=DATE-TIME:20180907T042500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-326@indico.inp.nsk.su DESCRIPTION:Speakers: Vadim Dudnikov (Muons\, Inc)\nPulsed and CW operatio n of negative ion radio frequency surface plasma source with a solenoidal magnetic field is described. Dependences of a beam current on RF power\, e xtraction voltage\, solenoid magnetic field\, gas flow are presented. Comp act design of RF SPS is presented. \n\nThe work was supported in part by U S DOE Contract DE-AC05-00OR22725 and by STTR grant\, DE-SC0011323.\n\nhttp s://indico.inp.nsk.su/event/11/contributions/326/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/326/ END:VEVENT BEGIN:VEVENT SUMMARY:Development of power supplies systems for CW negative ion sources at BINP DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-327@indico.inp.nsk.su DESCRIPTION:Speakers: Valery Savkin (Budker Institute of Nuclear Physics)\ nA series of Surface-Plasma negative ion Sources (SPSs) were developed and produced at BINP in the last 30 years. The energy of H- beams\, delivered by SPS is varied in the region 10 - 120keV\, the beam current – in the range from several mA CW up to several Amps in the long-pulsed operation [ 1]. \nA typical Power Supply system (PS) of the ion source provides the p owering and controlling of SPS circuits voltage\, current and timing. The high-current SPS uses a cesium deposition for H- yied enhancing and for t he co-extracted electrons flux decrease. As a result of cesium deposition the specific of SPS is the occasional HV breakdowns in ion optical system and an increased level of electric noise in the discharge and ion optical system circuits. This noise is inherent for the discharges in magnetic fi eld. An adequate PS and control systems were designed and manufactured in BINP workshop for the SPS reliable operation under these conditions [2]. T he report describes the principles\, schematic and design solutions of PS\ , produced at BINP for SPSs. \n\n[1]. Yu.I. Belchenko\, V.I. Davydenko\,P. P. Deichuli et al. Studies of ion and neutral beam physics and technology at the Budker Institute of Nuclear Physics SB RAS. *Physics - Uspekhi*\, * *61**\, #6\, (2018)\; doi: 10.3367/UFNe.2018.02.038305\n\n[2]. P. V. Zu barev\, A. D. Khilchenko\, A. N. Kvashnin\, D. V. Moiseev\, E. A. Puriga A .L.Sanin and V.Ya.Savkin. Computer System for Unattended Control of Negati ve Ion Source. AIP Conf. Proc. **1390**\, 634 (2011)\; doi: 10.1063/1.36 37435\n\nhttps://indico.inp.nsk.su/event/11/contributions/327/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/327/ END:VEVENT BEGIN:VEVENT SUMMARY:Damage simulations for large laser mirrors of laser neutralizer u nder proton and deutrons bombarding. DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-328@indico.inp.nsk.su DESCRIPTION:Speakers: Magomedrizy Atlukhanov (Budker Institute of Nuclear Physics)\nIn non resonant photon trap concept for neutralization of powerf ul negative ion beams one of problems is the bombarding of mirrors by high energy particles. They are occured due to scattering ions or atoms on res idual gas in transport channel. The simple estimation shows that it may be the main cause of mirror damage. \nThe simulation data of particles scat tering by background gas and their interaction with mirror materials will be presented.\n\nhttps://indico.inp.nsk.su/event/11/contributions/328/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/328/ END:VEVENT BEGIN:VEVENT SUMMARY:RF system test for CSNS external antenna negative hydrogen ion sou rce DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-329@indico.inp.nsk.su DESCRIPTION:Speakers: Weidong Chen (Institute of High Energy Physics\, Chi nese academy of sciences)\nAn RF H-minus source with external antenna is u nder development for the upgrade of China Spallation Neutron Source (CSNS) \, which requires a H$^-$ beam of 40 mA peak current at 25 Hz repetition r ate and 1 ms pulse length. The 2 MHz RF power is generated by a solid-stat e amplifier. Then a 50 kV insulation transformer is used to protect the am plifier from electric flash. The matching circuit consists of a 13:2 imped ance transformer\, a tunable capacitor\, and a water-cooled dummy load. In the off-line test\, the amplifier produces a maximum peak power of 80 kW at a duty factor of 2.75$\\%$. And the total transmission efficiency from the amplifier to the load is higher than 90$\\%$. The on-line plasma coupl ing test is in preparation and expected to start in June. Since the impeda nce of the RF plasma changes with RF power\, RF frequency\, and gas flow\, an RF network without impedance transformer is under development to match the impedance of plasma within a wider range.\n\nhttps://indico.inp.nsk.s u/event/11/contributions/329/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/329/ END:VEVENT BEGIN:VEVENT SUMMARY:Towards efficient integration of cusp and dipole filter magnets in a compact H- source DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-330@indico.inp.nsk.su DESCRIPTION:Speakers: Carlo Baltador (LNL - INFN)\nThe RF compact negative ion source NIO1 installed at Consorzio RFX\, in collaboration with INFN-L NL\, allows to test several magnetic filter configuration inside the ion s ource and their relation with the fringe field of the electrons suppressio n magnets embedded into the extraction grid (by convention z is the extrac tion axis\, while extraction grid magnets deflects electrons along y direc tion). NIO1 has been designed to produce 9 H- beamlets (in a 3x3 pattern)\ , each with current below 2 mA and 20 kV acceleration voltage in this firs t phase without source cesiation and up to 15 mA and 60 kV after careful c esiation.\nSince no cesium has been used yet in NIO1\, the negative ion pr oduction relies on the volume process only. The most important role in ord er to improve the efficiency of this process is played by the magnetic fil ter field inside the source (of course\, when NIO1 cesium operation will b egin\, filter effect will be mixed with cesium effect and acceleration vol tage holding). The original source filter had an intensity up to Bx= 3 mT and it was provided by current I circulating in the plasma electrode\, wit h source performance improving with Bx. To increase filter strength\, furt her current increase is impractical. Therefore\, we need to develop hybrid systems\, where part of the filter is provided by permanent magnets (PMF) and another part may be tuned by current (CDF). The several possible conf igurations are here fully described and simulated with Opera3D. In particu lar\, the cusp field\, which confines NIO1 plasma can be partly altered\, to provided also a dipole field. A simple PMF concept\, giving By = 15 mT was designed and tested with no particular success\, which can be explaine d by excessive value or by field orientation: simulations proving detrimen tal effect of filter and deflection interference are shown. More elaborate concepts\, providing Bx > 4 mT up to 12 mT (depending on PMF sizes) are h ere described.\nThe aim of this contribution is to show the studies of an innovative configuration for cusp magnets\, together with an innovative te chnique to shape permanent magnets\, in order to produce a filter field pa rallel (PMF) to the one generated by mean of electric current (CDF)\, retr ieving also the possibility of field tuning by changing the current in the circuit. The finite element code OPERA 3D is used for this investigation and to study the effect of different solutions on beamlet optics.\n\n\nTh is work was set up with partial financial support of F4E/EUROfusion.\n\nht tps://indico.inp.nsk.su/event/11/contributions/330/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/330/ END:VEVENT BEGIN:VEVENT SUMMARY:Initial results of optical emission spectroscopy based on a collis ional radiative modeling in the RF hydrogen negative ion source in NFRI DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-331@indico.inp.nsk.su DESCRIPTION:Speakers: Byungkeun Na (National Fusion Research Institute)\nA prototype radio frequency (RF) negative hydrogen ion source is under deve loping under the cooperative research project between the National Fusion Research Institute (NFRI)and the Korea Atomic Energy Research Institute (K AERI). An inductively coupled plasma (ICP) of 2 MHz radio frequency is dev eloped so far\, and three grids accelerator and Cesium injector will be de veloped in the near future. For the plasma diagnostics system\, optical em ission spectroscopy (OES) based on a collisional-radiative (CR) modelling is on preparation with the 3-lens fiber collector and a spectrometer. The advantages of CR-OES are as followings: 1. It is a non-invasive method tha t is usable even in the high power experimental condition. 2. It provides plasma parameters as well as the densities of ion species. As a first stag e of the diagnostics setup\, the results from the CR-OES will be compared to the RF compensated Langmuir probe measurement. The application of the m ethod to the neutral beam injector in Korea Superconducting Tokamak Advanc ed Research (KSTAR)\, a positive ion source based on arc discharge\, and i ts result will be introduced as well.\n\nhttps://indico.inp.nsk.su/event/1 1/contributions/331/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/331/ END:VEVENT BEGIN:VEVENT SUMMARY:Diagnostics of Caesium emission from SPIDER caesium oven prototyp e DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-358@indico.inp.nsk.su DESCRIPTION:Speakers: Emanuele Sartori (Consorzio RFX - Università di Pad ova)\nThe use of caesium vapour is mandatory in plasma sources for negativ e ion beams to achieve a sufficient negative ion density. In the SPIDER io n source\, three caesium ovens will provide a sufficiently high caesium fl ux to the walls of the ion source\, but also a relatively even caesium dis tribution in the ion source volume. In order to qualify the caesium ovens in terms of repeatability of the evaporated caesium flow\, and to characte rize the caesium flux emitted from its nozzle\, a set of diagnostics was i nstalled in the small test facility CAesium Test Facility (CATS). This pap er reports on the present configuration of the diagnostic set-up. Surface ionization probes are installed in front of the nozzle apertures. Movable surface ionization detectors are used to reconstruct the angular distribut ion of the emission. A quartz microbalance is installed at a fixed positio n\, to provide the cumulated caesium over time. Finally\, the laser absorp tion spectroscopy measures the line-integrated caesium density. An example of combined measurement is presented.\n\nhttps://indico.inp.nsk.su/event/ 11/contributions/358/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/358/ END:VEVENT BEGIN:VEVENT SUMMARY:Measurement of the space charge effect of a negative hydrogen ion beam. DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-332@indico.inp.nsk.su DESCRIPTION:Speakers: Iaroslav Kolesnikov (Budker Institute of Nuclear Phy sics)\nFor the development of boron neutron capture therapy at the Budker Institute of Nuclear Physics it\nwas created a source of epithermal neutro ns [1]\, based on a tandem accelerator with vacuum\ninsulation. In the acc elerator it was obtained a stationary proton beam with 2 MeV energy and up to\n5 mA current [2]. In order to increase the proton current\, it has be en in depth studied the transport\nof a negative hydrogen ion beam and its injection into an accelerator in detail. To measure current\nand profile it was used a wire scanner OWS-30 (D-Pace\, Canada)\, supplemented with ri ngs under\nnegative potential for suppressing secondary electron emission. The current and the transverse\nprofile of the beam were measured as a fu nction of the residual gas pressure regulated by the\ninstalled leak. It i s found that\, while the pressure of the residual gas is increasing\, the current and\nthe transverse beam size are decreasing. The current decrease is caused by stripping\, the decrease in\nthe transverse dimension is due to the weakening of the space charge effect\, due to the increasing\namou nt of positive ions. The density of the negative hydrogen ion current has a maximum value at\nthe intermediate value of the residual gas pressure. B ased on the results of measurements of the\nwire scanner\, the radial prof ile of the beam was obtained\, which turned out to be hollow due to the\ne ffect of the space charge of the beam and the spherical aberrations of the magnetic lenses. The\npaper presents and discusses the results of numeric al simulations and experiments.\nRecommendations are given for injection c onditions for increasing the proton current. \n\nReferences\n\n1. B. Bayan ov\, V. Belov\, E. Bender\, et al.\, 1998. *Accelerator based neutron sour ce for the neutron-capture and fast neutron therapy at hospital*. Nucl. In strum. Methods Phys. Res. A **413**\, 397–426. \n\n2. A. Ivanov et al. * Suppression of an unwanted flow of charged particles in a tandem\naccelera tor with vacuum insulation*. JINST\, **11**\, P04018 (2016)\n\nhttps://ind ico.inp.nsk.su/event/11/contributions/332/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/332/ END:VEVENT BEGIN:VEVENT SUMMARY:Design of the Calorimeter for High-Power RF Negative Ion Source DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-333@indico.inp.nsk.su DESCRIPTION:Speakers: Wendou Yan (State Key Laboratory of Advanced Electro magnetic Engineering and Technology\, Huazhong University of Science and T echnology)\nTo study and optimize negative ion production for the HUST (Hu azhong University of Science and Technology) radio frequency negative ion source\, an instrumented calorimeter is under construction with the aim of testing beam characteristics and verifying the source proper operation. B ased on the comparative analysis of different calorimeter structures and a ctual requirements of the HUST source\, this paper chooses a quasi-adiabat ic physical structure for calorimeter which is composed of 8×8 copper tar gets and a cooling backplane for beam diagnosis. For this structure\, the main error of existing beam power calculation model comes from water-cooli ng\, which is corrected and greatly reduced in this paper. The calorimeter can sustain the high power loads (up to 3 MW/m2) and can generally reflec t the distribution of it. \n According to the thermal analysis and phys ical requirements\, a calorimeter has been designed and manufactured. In a ddition\, the experiment has been carried out. This paper gives an overvie w of the design and the experiment result.\n\nhttps://indico.inp.nsk.su/ev ent/11/contributions/333/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/333/ END:VEVENT BEGIN:VEVENT SUMMARY:Effect of light-mass ion species on plasma characteristics in NIFS -RNIS DTSTART;VALUE=DATE-TIME:20180903T064000Z DTEND;VALUE=DATE-TIME:20180903T070500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-334@indico.inp.nsk.su DESCRIPTION:Speakers: Haruhisa Nakano (National Institute for Fusion Scien ce)\nDegradations of ion source performance were found in deuterium operat ion of negative ion source for Neutral Beam Injector (NBI) on Large Helica l Device (LHD): lower ion beam current efficiency for discharge power\, hi gher electron current ratio to ion beam current and more intense Cs atom e mission (related with sputtering) in the same Cs tank temperature operatio n. We changed pressure inside discharge chamber\, bias voltage between arc chamber and plasma grid\, Cs tank temperature (Cs seeding flux) and disch arge duration (discharge chamber wall temperature) to optimize beam inject ion power to the LHD.\n It is expected that these degradation and varia tion of optimal operation parameter from hydrogen to deuterium operations are associated to differences of negative ion yield efficiency on plasma g rid surface covered by cesium\, physical and/or chemical sputtering\, and plasma parameter variation by ion mass. For the sputtering and plasma para meter variation\, helium and helium mixed hydrogen discharges as well as p ure hydrogen and deuterium are useful. Simultaneous several plasma paramet er measurements are necessary to investigate the physical differences betw een hydrogen and deuterium operation in the large scale negative ion sourc e for fusion. Experiment is performed with National Institute for Fusion S cience-Research and development Negative Ion Source (NIFS-RNIS) which is t he most suitable ion source for this experiment because NIFS-RNIS was the same type of the negative ion source for NBI on LHD. And NIFS-RNIS has man y diagnostics: movable Langmuir Probe (ne\, Te and Vs profile)\, movable c avity ringdown technique (nH- profile)\, millimeter wave interferometer (n e)\, multi-channel laser absorption spectroscopy for cesium atom (nCs dist ribution)\, optical emission spectroscopy (hydrogen\, deuterium\, helium a nd cesium emission). We will present the differences among hydrogen\, deut erium\, helium mixed hydrogen discharges in NIFS-RNIS.\n\nhttps://indico.i np.nsk.su/event/11/contributions/334/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/334/ END:VEVENT BEGIN:VEVENT SUMMARY:Sputter negative ion source at BINP Accelerator Mass Spectrometer DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-335@indico.inp.nsk.su DESCRIPTION:Speakers: Eugene Konstantinov (Budker Institute of Nuclear Phy sics)\nAccelerator mass spectrometry is a powerful analytic method used in archaeology\, geology\, biology and medicine. Due to its huge resolution\ , even single atoms are statistically observable for standard 1 or 3 mg ta rget samples. The main problem of the method is to clear the ions beam off the molecular isobars. The use of the negative ions and stripper to chang e the charge state of ions solves the problem. Thus\, one of the important part of the accelerator mass spectrometer is the sputtering negative ion source. Mainly the carbon is of the interest for accelerator mass spectrom etry but the mass spectrum is just slightly limited with some elements not producing negative ions. The carbon negative ion sputtering source\, deve loped at Budker Institute of Nuclear Physics\, is working succesfully at t he Accelerator Mass-Spectrometer of the Center of Kaynozoy Geochronology. The source operating characteristics will be presented. The construction\, results of operation and status of the source will be discussed.\n\nhttps ://indico.inp.nsk.su/event/11/contributions/335/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/335/ END:VEVENT BEGIN:VEVENT SUMMARY:Effects of the extraction voltage on the H- beam optics for H- ion sources DTSTART;VALUE=DATE-TIME:20180906T030000Z DTEND;VALUE=DATE-TIME:20180906T032500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-336@indico.inp.nsk.su DESCRIPTION:Speakers: Max Lindqvist (Keio University)\n$\\:\\:\\:\\:\\:\\: $Development of $H^-$ ion sources which can produce high beam intensity wi th a small beam divergence angle is useful in plasma heating systems for m agnetic fusion reactors and accelerators for high-energy physics. Since on e of the main requirements for the extracted particle beam in Linac4 $H^-$ ion source is to minimize the beam divergence and emittance\, it is of vi tal importance to further our understanding of the extraction mechanisms. However\, as of today\, the beam formation mechanisms in such $H^-$ ion so urces are yet to be fully understood.\n \n$\\:\\:\\:\\:\\:\\:$In previous work by S. Abe the dependence on the beam divergence angle of the extracti on voltage by using a 2D Particle In Cell (PIC) model for the extraction r egion of $H^-$ ions source for Linac4 was analyzed [1]. It was shown that the divergence angle has a minimum value and that this minimum value can b e further decreased by taking charge exchange and elastic collisions into account\, which play a key role in the flow reversal of $H^-$ ions produce d at the PG. The $H^-$ ions extracted from the bulk plasma region due to flow reversal has smaller divergence angle than $H^-$ ions extracted direc tly from the Plasma Grid (PG) surface. The extracted negative ion beam thu s consists of two components: the beam core and the beam halo. [2]\n \n$\\ :\\:\\:\\:\\:\\:$The purpose of this study is to clarify the extraction me chanisms of the surface produced $H^-$ ions\, in order to optimize the bea m optics by varying the PG shape in negative ion sources such as the Linac 4 $H^-$ ion source. We\, therefore\, intend to evaluate the extracted $H^- $ beam divergence angle for various extraction voltages by using a 3D PIC model for the geometry of Linac4 $H^-$ ion source [3]. Furthermore\, we in tend to survey the extraction mechanisms of $H^-$ ions produced at the PG surface. In particular\, the tendency of velocity reversal due to elastic collisions and charge exchange of the surface produced $H^-$ ions will be studied.\n \n$\\:\\:\\:\\:\\:\\:$The results of the extraction mechanism o f the surface produced $H^-$ ions are presented. The tendency of the resul ts corresponds to experimental measurements and contributes to validating the 3D PIC model by comparison with experiments and thus further improves our understanding of the extraction mechanisms of $H^-$ ions.\n\n\nReferen ces\n\n[1] S. Abe\, S. Nishioka\, S. Mattei\, A. Hatayama\, and J. Lettry \, "Effects of the extraction voltage applied by the puller-electrode on t he H- extraction in the Linac4 negative ion source"\, AIP Conference Proce edings 1869\, 030051 (2017)\,\n\n[2] S. Abe\, Master’s Thesis\, Keio Uni versity 2018\,\n \n[3] S. Nishioka\, \, I. Goto\, K. Miyamoto\, A. Hatayam a\, and A. Fukano\, "Study of ion-ion plasma formation in negative ion sou rces by a three-dimensional in real space and three-dimensional in velocit y space particle in cell model"\, J. Appl. Phys. 119\, 023302 (2016).\n\nh ttps://indico.inp.nsk.su/event/11/contributions/336/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/336/ END:VEVENT BEGIN:VEVENT SUMMARY:Complete compensation of criss-cross deflection in a negative ion accelerator by magnetic technique DTSTART;VALUE=DATE-TIME:20180905T083000Z DTEND;VALUE=DATE-TIME:20180905T085500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-337@indico.inp.nsk.su DESCRIPTION:Speakers: Daniele Aprile (Consorzio RFX)\nDuring 2016\, a join t experimental campaign was carried out by QST and Consorzio RFX on the N egative Ion Test Stand (NITS) at the QST Naka Fusion Institute\, Japan\, i n order to validate some design solutions adopted in MITICA which is the f ull-scale prototype of the ITER NBI\, presently under construction at Cons orzio RFX\, Padova\, Italy.\n\nThe main purpose of the campaign was to tes t a novel technique\, for suppressing the beamlet criss-cross magnetic def lection. This new technique\, involving a set of permanent magnets embedde d in the Extraction Grid\, named Asymmetric Deflection Compensation Magnet s (ADCM)\, is potentially more performing and robust than the traditional electrostatic compensation methods.\n\nThe results of this first campaign confirmed the effectiveness of the new magnetic configuration in reducing the criss-cross magnetic deflection. Nonetheless\, contrary to expectation s\, a complete deflection correction was not achieved. By analyzing in det ail the results\, we found indications that a physical process taking plac e just upstream of the plasma grid was giving an important contribution to the final deflection of the negative ion beam. This process appears to be related to the drift of negative ions generated in the plasma source\, in presence of magnetic field transverse to the extraction direction\, and r esults in a non-uniform ion current extraction at meniscus.\n\nTherefore\, the numerical models adopted in the design was improved by including this previously disregarded effect\, so as to obtain a much better matching wi th the experimental results. On this basis\, new permanent magnets were de signed and installed on the Extraction Grid of NITS. A second QST-Consorzi o RFX joint experimental campaign was then carried out in 2017\, demonstra ting the complete correction of the criss-cross deflection and confirming the validity of the adopted solution and of the hypothesis behind the new models.\n\nThis contribution presents the results of the second joint expe rimental campaign on NITS along with the overall data analysis of both cam paigns\, and the description of the improved models. A general picture is given of the relation among magnetic field\, beam energy\, meniscus non-un iformity and beamlet deflection and divergence\, constituting a useful dat abase for the design of future machines.\n\nhttps://indico.inp.nsk.su/even t/11/contributions/337/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/337/ END:VEVENT BEGIN:VEVENT SUMMARY:Measurement of Negative Carbon Ions near a Plasma Deposited Carbon Thin Film by Laser Photodetachment DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-338@indico.inp.nsk.su DESCRIPTION:Speakers: Yuito Ikeda (Doshisha University)\nPlasmas to prepar e functional carbon films contain negative carbon ions which should modify the sheath structure on the formed films. The density distributions of ca rbon negative ions in the sheath region around the carbon film must critic ally determine the property of the film. A DC photodetachment method was u tilized to measure negative carbon ion density in the plasma formed by dis charge between a carbon hollow cathode and a hollow anode.\n\nA DC glow di scharge was maintained between carbon electrodes of cylindrical 19 mm inne r diameter\, 23 mm outer diameter and 45 mm long. These electrodes were pl aced 14 mm apart facing each other. The chamber was made of electrically i nsulating borocilicate glass. A Langmuir probe is inserted into the chambe r in the direction perpendicular to the carbon electrode tubes. The positi on of the probe tip can be adjusted in the direction along the probe. A gl ass substrate for a thin film deposition was set near the carbon cathode. By using a 808 nm (1.53 eV) semiconductor laser exceeding the electron aff inity of negative carbon ions (1.27 eV)\, a signal corresponding to the lo cal negative ions density was measured to construct the spatial distributi on of negative ions. The laser passed through the axis of the carbon cylin drical electrodes. The photodetachment signal induced onto the discharge c urrent was detected with a two-phase lock-in amplifier synchronized to the amplitude modulation of the laser power. The effect on the formed film du e to the presence of negative ions in the sheath region is investigated th rough X-ray diffraction and scanning electron microscope.\n\nhttps://indic o.inp.nsk.su/event/11/contributions/338/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/338/ END:VEVENT BEGIN:VEVENT SUMMARY:Plasma Electrode Structure Suitable for H$^-$ Extraction from a Be rnas Type Ion Source DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-339@indico.inp.nsk.su DESCRIPTION:Speakers: Masaki Ishikawa (Doshisha University)\nEffect of the plasma electrode position upon the negative hydrogen (H$^-$) ion beam cur rent extracted from a Bernas type ion source have been studied. In the pre vious study plasma electrode located inside of the arc chamber covered alm ost all length along the plasma column sustained in a liner confinement ma gnetic field. In this study the amount of H$^-$ beam current was measured as a function of the voltage to the plasma electrode\, which was located o utside of the arc chamber. The area of the plasma electrode exposed to the ion source plasma was reduced to 26 mm × 85 mm.\n\nEffect of filament ma terials on the H$^-$ ion beam production efficiency of the Bernas type ion source has been also experimentally studied. Tungsten and tantalum are te sted for comparison. Dependence of H$^-$ ion current and that of extracted electron current were studied by applying bias voltage on the plasma elec trode for two different filament materials. H$^-$ beam current increased b y about 200% with the present plasma electrode structure compared with the previous design. The amount of co-extraction electron current was reduced to two thirds of the original amount. More than 30% increase in H$^-$ ion beam current was observed with the tantalum filament. The amount of co-ex traction electron current decrease by 40% with the tantalum filament as co mpared with that for a tungsten filament.\n\nhttps://indico.inp.nsk.su/eve nt/11/contributions/339/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/339/ END:VEVENT BEGIN:VEVENT SUMMARY:Study of H- extraction from a single-hole plasma electrode of C12A 7 electride DTSTART;VALUE=DATE-TIME:20180903T074000Z DTEND;VALUE=DATE-TIME:20180903T080500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-340@indico.inp.nsk.su DESCRIPTION:Speakers: Mamiko SASAO (Doshisha University)\nRecently\, it ha s been reported that a high production rate of negative hydrogen\nion (H-) was observed from a nano-porous C12A7 electride surface immersed in\nhydr ogen/deuterium low-pressure plasmas [1].  The H- ion energy spectrum seem ed to indicate that the dominant process leading to H- ion formation was t hrough kinetic desorption induced by low energy ions. Fundamental underst anding of the production mechanism is not fully clarified yet.  Negative ions can be produced through (1) charge exchange(electron pick-up) reflect ion process and (2) desorption process by sputtering.\nWhen the plasma ele ctrode was fabricated with the C12A7 electride\, it is not clear\nwhether the high production rate through desorption process is effective in a real \nion source\, or not. In addition\, it is not clear whether the high prod uction rate of H-\nions on the C12A7 electride is owing to the characteris tic feature of the low-work\nfunction\, or the cage structure that contain s H- ions in it.  \n Present work deals with negative ion producti on on a C12A7 electride\nsurface for a cesium free ion source\, and H- ext raction from a single-hole plasma\nelectrode. In order to investigate thes e problems\, a small device with an ECR\nplasma source and C12A7 electride plasma grid has been constructed. The work\nfunction of the plasma gird s urface can be monitored by injecting lasers of various\nwavelength\, and e xtracted H- current will be measured.\n\n[1] M. Sasao\, et al\, Applied Ph ysics Express 11\, 066201 (2018)\n\nhttps://indico.inp.nsk.su/event/11/con tributions/340/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/340/ END:VEVENT BEGIN:VEVENT SUMMARY:Design of the RF Negative Hydrogen Ion Source at HUST DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-341@indico.inp.nsk.su DESCRIPTION:Speakers: Chen Zuo (Huazhong University of Science and Technol ogy)\nThe radio frequency driven source for negative hydrogen ions\, to in vestigate the physics of production and extraction of the H$^-$ ions\, is under construction at Huazhong University of Science and Technology. Plasm a generated from RF driver expands to the surface of plasma grid. Extracti on system with three grids is designed to extract and accelerate the H$^-$ beams. The design parameters of the ion source are: beam current 0.35 A\; extraction voltage: 10 kV\; accelerator voltage: 20 kV\; pulse length\n\n https://indico.inp.nsk.su/event/11/contributions/341/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/341/ END:VEVENT BEGIN:VEVENT SUMMARY:Negative-ion production study on nanoporous 12CaO.7Al2O3 electride surface in low pressure H2 plasma DTSTART;VALUE=DATE-TIME:20180907T020000Z DTEND;VALUE=DATE-TIME:20180907T022500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-342@indico.inp.nsk.su DESCRIPTION:Speakers: Roba Moussaoui (Aix-Marseille University)\nIn ITER a nd Demo devices\, the heating of fusion plasma will be mainly provided by the injection of 1 MeV neutral deuterium atom (D) beams into tokamak. Such energetic neutrals are delivered by neutral beam injection (NBI) device. The key component of ITER NBI device is D- negative ion source\, where a D - current density of 200 A/m2 is required. ITER negative ion (NI) source i s based on Cs injection. It is nowadays the only scientific solution to re ach such high D- negative ion current. Cesium (Cs) is injected in vapor st ate inside negative ion source. It deposits on the surface of plasma grid. Deposition of Cs on the grid lowers the material work function which reac hes value close to 2 eV. This effect increases electron capture efficiency by particles from the plasma backscattered by the surface. Therefore\, hi gh NI yields is produced. However\, severe drawbacks to the use of Cs have been identified\, hence a strong reduction of Cs consumption or its elimi nation from the fusion negative-ion sources is highly valuable. For this r eason\, we are working on H-/D- negative-ion surface production in Cs-fre e H2/D2 plasmas.\nSurface negative ion production measurements are perform ed in the diffusion chamber of a plasma reactor [1]. The sample is placed inside the plasma. It is negatively biased with respect to the plasma pote ntial. So\, the plasma positives ions are accelerated towards the sample s urface by the electric field formed in the sheath. The positive ions bomba rdment leads to a negative ions surface production on the surface. The pro duced negative ions are accelerated towards the plasma and self- extracted from the plasma to a mass spectrometer\, where they are detected accordin g to their energy. This measurement gives the negative ion energy distribu tion function (NIEDF).\nIn this work\, surface negative ions production is studied on Nanoporous 12CaO. 7Al2O3 electride surface. The material surfa ce is exposed to low pressure hydrogen plasma created by a 2.45 GHz genera tor. NIEDFs were recorded in following experimental conditions: 1 Pa H2 ga s pressure and microwave injected power of 60 W. The influence of surface temperature\, bias and plasma exposure time on negative-ion yield is inves tigated. The target was negatively biased at 20 - 170 V\, and it was heate d from room temperature to 500°C. The effect of the duration of high ener gy H3+ bombardment on material surface was also studied. Different NIEDF m easurement on Nanoporous 12CaO. 7Al2O3 electride surface are compared to N IEDFs measured on our reference material HOPG (highly oriented pyrolitic g raphite) and on molybdenum Mo surface. A high production rate of H- negati ve ions was observed from Nanoporous 12CaO. 7Al2O3 electride surface compa red to Mo surface. The NIEDF peak intensity on electride surface is 25 tim es the NIEDF peak intensity on Mo surface at a surface bias of -20 V [2]. This high production of NI yield on material surface may be attributed to its low work function of 2.4- 2.7 eV. In this contribution\, we shows tha t the electride material has potentials to be used as a production surface of cesium- free negative ion sources for neutral beam injectors in nuclea r fusion.\n\n[1]G. Cartry\, D. Kogut\, K. Achkasov\, J.-M. Layet\, T. Fare ly\, A. Gicquel\,J. Achard\, O. Brinza\, T. Bieber\, H. Khemliche\, P. Ron cin\, and A. Simonin\, New J. Phys\, 19\, 025010 (2017)\n\n[2]M. Sasao\, R . Moussaoui\, D. Kogut\, J. Ellis\, G. Cartry\, M. Wada\, K. Tsumori\, and H. Hosono\, Appl. Phys. Express 11\, 066201 (2018)\n\nhttps://indico.inp. nsk.su/event/11/contributions/342/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/342/ END:VEVENT BEGIN:VEVENT SUMMARY:Development of the Cs-seeded RF negative ion beam source in Korea DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-343@indico.inp.nsk.su DESCRIPTION:Speakers: Min Park (Korea Atomic Energy Research Institute)\nT he development of a Cs-seeded RF negative ion beam source has been started as a collaborative research project between two institutes KAERI and NFRI \, towards ITER neutral beam injector (NBI) technology. The final performa nce objective of the source is to produce 200 keV\, 0.5 A deuterium ion be ams. The preliminary experiments for the performance evaluation of the RF plasma source was conducted. The RF-compensated Langmuir probe was used to measure the electron energy probability functions (EEPFs)\, and the elect ron temperatures and the electron densities were calculated from the obtai ned EEPFs. The obtained plasma parameters in this way were used to calcula te various RF source characteristic parameters. In particular\, the negati ve ion density were estimate through the balance model calculations\, in w hich the negative ions are assumed to be produced mainly by the volume pro duction mechanism\, that is\, the dissociative attachments of low energy e lectrons to vibrationally excited hydrogen molecules. The extraction and t he acceleration grids for the beam energy up to 30 keV were installed and the beam extraction experiments were carried out to check the actual perfo rmance of the source. Then\, the evaporated Cs was seeded into the expansi on chamber controlled by the dispenser current. In order to find the optim um operating conditions for high-performance ion beams\, various beam extr action experiments were accomplished with several external parameters such as the Cs-evaporation rate\, the temperature of the plasma grid (PG)\, et c. Detailed system description and the experimental results are presented. \n\nhttps://indico.inp.nsk.su/event/11/contributions/343/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/343/ END:VEVENT BEGIN:VEVENT SUMMARY:Beam Intensity Bottleneck Specification and 100 mA Operation of J- PARC Cesiated RF-Driven H$^-$ Ion Source DTSTART;VALUE=DATE-TIME:20180904T023000Z DTEND;VALUE=DATE-TIME:20180904T025500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-344@indico.inp.nsk.su DESCRIPTION:Speakers: Akira UENO (J-PARC)\nThe Japan Proton Accelerator Re search Complex (J-PARC) cesiated RF-driven Hˉ ion source has been stably operated for about four years. The J-PARC RFQ linac successfully accelerat ed the J-PARC requirement intensity of 60 mA\, when a 70 mA beam was injec ted from the source. The high intensity beam with transverse emittances su itable for the RFQ is produced with several unique measures\, such as\, sl ight water molecules (H2Os) addition into hydrogen plasma\, a low temperat ure (about 70ºC) operation of 45º-tapered plasma electrode with a 16-mm thickness\, argon and/or nitrogen elimination in the hydrogen plasma along with filter-field optimization\, and so on. In order to specify the beam intensity bottleneck of the source and derive the optimal plasma\, extract ion and ground electrode shapes\, the higher extraction and acceleration v oltages (Vext and Vacc) were examined. A 100 mA beam\, whose about 92 mA b eam has transverse emittances used for a common RFQ design\, was stably op erated with a duty factor of 5 % (1 ms x 50 Hz) by using the Vext and Vacc of 12 kV and 50 kV\, respectively. This great progress with important inf ormation on the space-charge limited bottlenecks in the extraction and acc eleration gaps will derive the optimal electrode shapes for the J-PARC ope ration and realize the next generation benchmark Hˉ ion source for high i ntensity and high energy Linacs.\n\nhttps://indico.inp.nsk.su/event/11/con tributions/344/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/344/ END:VEVENT BEGIN:VEVENT SUMMARY:Studies of the Cs Dynamics in Large Ion Sources using the CsFlow3D Code DTSTART;VALUE=DATE-TIME:20180905T030000Z DTEND;VALUE=DATE-TIME:20180905T032500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-345@indico.inp.nsk.su DESCRIPTION:Speakers: Alessandro Mimo (Max-Planck-Institut für Plasmaphys ik)\nLarge negative ion sources for neutral beam injection rely on surface production of negative ions on a converter surface (plasma grid) in a low temperature plasma environment. To increase the negative ion production e fficiency and reduce the amount of co-extracted electrons\, the work funct ion of the plasma grid is reduced by using Cs\, which is evaporated in the source and redistributed by the plasma on the inner surfaces. In order to avoid a degradation of the plasma grid work function during the beam puls e a sufficient flux of Cs onto the plasma grid needs to be maintained\, es pecially for long pulses (several hundred seconds). The Cs flux is influen ced by the plasma distribution in the source\, which can be affected by a vertical drift due to the magnetic filter field. In addition\, the presenc e of a bias potential between the plasma grid and the other source walls c an affect the plasma potential profile and thus the flux of Cs$^{+}$ ions. To investigate the effect of plasma drift on Cs dynamics\, the Monte Carl o code CsFlow3D has been used to simulate long pulses for the source at th e ELISE test facility (half the size of the ITER-NBI source) and a vertica l asymmetry of the plasma profiles\, i.e. plasma density\, electron temper ature and plasma potential\, has been implemented. The Cs flux onto the pl asma grid (both neutral and Cs$^{+}$ ions)\, the energy distribution of th e Cs$^{+}$ ions impinging the grid (depending on the bias potential of the plasma grid) as well as the neutral Cs density resulting from the simulat ions will be presented. The latter will be directly compared with the expe rimental data from TDLAS (Tunable Diode Laser Absorption Spectroscopy). Fu rther on\, an alternative configuration of the Cs oven that relies on the direct evaporation close to the plasma grid has been simulated\, in order to achieve a caesiation method that is independent from the plasma paramet ers and capable of delivering the required flux during long pulses.\n\nhtt ps://indico.inp.nsk.su/event/11/contributions/345/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/345/ END:VEVENT BEGIN:VEVENT SUMMARY:Development of a new beamlet monitor system: time resolution and p hase space structure DTSTART;VALUE=DATE-TIME:20180906T050000Z DTEND;VALUE=DATE-TIME:20180906T052500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-346@indico.inp.nsk.su DESCRIPTION:Speakers: Yasuaki HABA (Nagoya University / National Institute for Fusion Science)\nDevelopment of negative ion sources and development of the accelerator of negative ion beams are of crucial importance for nuc lear fusion research. In order to evaluate beam optics\, and to investigat e the characteristics of meniscus formed between negative ion beam region and plasma region\, detaild measurement of beam property is required. Ther efore\, we have developed a new beamlet monitor system to evaluate negativ e ion beam properties in experiments. \n The beamlet monitor system for ne gative ion beams has four diagnostics in one hexagonal box\, which can be moved remotely in the vertical direction (y-direction in the experiment) b y a linear drive system. One diagnostic is fast beamlet monitor (FBM) with 32-channel electrode array (8x4) for beam current profile measurement. Th e time resolution is up to 50 MHz for electrical circuit and data aquisiti on\, and the space resolution is 4.1 mm in the horizontal (x-direction) an d 4.9 mm in the vertical. The other diagnostics are pepper pot-type phase space structure analyzers (PPSA). The copper plate with two-dimensional pi nhole array (18x14) and kapton foil are utilized for detecting beam burn p attern\, which shows the information of phase space structure.\n The hexag onal box is installed in NIFS neutral beam test stand (NIFS-NBTS). The det ector can be switched by rotating the box on a shot-by-shot basis. Therefo re\, the beam information from different diagnostics are obtained with alm ost the same beam condition.\n The demonstrations of beam measurement with the beam monitor system were performed. In the case of FBM\, it was confi rmed that the secondary electron current can be suppressed with the applic ation of DC bias of +70 V to the electrodes\, and the absolute value of th e beam current was obtained. The two-dimensional beam profile was also obt ained by detailed scan of the detector position with the linear drive. In the case of PPSA\, the clear beam burn pattern was obtained on the kapton foil\, and the phase space structure was constructed by the burn pattern.\ n In the symposium\, the details of the beamlet monitor system and the ini tial results in the experiments will be presented\, and the comparison of the two dimensional beam-let profiles obtained by FMB and PPSA will be dis cussed.\n\nhttps://indico.inp.nsk.su/event/11/contributions/346/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/346/ END:VEVENT BEGIN:VEVENT SUMMARY:Gasdynamic ECR ion source for negative ion production DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-347@indico.inp.nsk.su DESCRIPTION:Speakers: Roman Lapin (Institute of Applied Physics of Russian Academy of Sciences)\nH^- ion sources are needed in various areas of nowa days physics\, such as for beam injection into cyclotrons and storage ring s and for plasma heating in experimental facilities studying the possibili ty of thermonuclear fusion. According to the recently proven fact that gas dynamic ECR ion source based on ECR discharge in a simple mirror trap coul d be very efficient for proton beam production\, we use that gasdynamic pl asma source at the first stage of volumetric ion production through dissoc iative electron attachment. Experiments were performed with 37 GHz\, up to 100 kW gyrotron radiation in a dual-trap magnetic system\, which consists of two equal simple mirror traps. The first trap was used for plasma prod uction under ECR conditions with parameters listed above. Dense hydrogen p lasma flux from the first trap was allowed to flow into the second trap th rough a perforated plate\, which prevented propagation of heating microwav es into the second one. That helps to separate "hot" and "cold" electrons generation areas. In the current work we present the recent experimental r esults on this topic. The significant difference compared with previous ex periments is preliminary cleaning the chambers with a warm-up and a long p umping out. We achieved the negative ion current density on the level of 8 0 mA/cm^2 with the 1 mm aperture of plasma electrode.\n\nhttps://indico.in p.nsk.su/event/11/contributions/347/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/347/ END:VEVENT BEGIN:VEVENT SUMMARY:The RF H$^-$ Ion Source Project at RAL DTSTART;VALUE=DATE-TIME:20180904T043000Z DTEND;VALUE=DATE-TIME:20180904T045500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-348@indico.inp.nsk.su DESCRIPTION:Speakers: Olli Tarvainen (STFC Rutherford Appleton Laboratory) \nA Penning-type surface-plasma ion source source has provided H$^{-}$ bea m for the ISIS spallation neutron and muon facility at the Rutherford Appl eton Laboratory (RAL) for nearly 35 years. The source delivers 55 mA of H$ ^{-}$ beam current with a beam duty factor of 1.5 $\\%$ at 50 Hz repetitio n rate and a transverse 4-rms emittance $\n\nhttps://indico.inp.nsk.su/eve nt/11/contributions/348/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/348/ END:VEVENT BEGIN:VEVENT SUMMARY:Global Model of Multi-Chamber Negative Hydrogen Ion Sources with M ulti-aperture Extraction System DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-349@indico.inp.nsk.su DESCRIPTION:Speakers: Seth Veitzer (Tech-X Corporation)\nConventional glob al models for plasma discharge chambers solve volume averaged continuity e quations\, electron and total energy equations supplemented by quasineutra lity condition in order to obtain plasma components number densities and e lectron and heavy species temperatures. These models are limited to single chamber designs. Their main advantage is a rapid evaluation of parameter space that is used to select the most important plasma components and chem ical reactions\, and obtain basic plasma scaling parameters.\n\nWe present a new global model for simulations of multi-chamber negative hydrogen ion sources. This is an extension of our previous verified global model for a single-chamber design. Our new model consists of separate global models f or each chamber with interface boundary conditions that are solved simulta neously to get macroscopic parameters (number densities and temperatures) of all species in each chamber. The model includes electrons\, hydrogen mo lecules with all vibrational states ($H_2(v)$)\, hydrogen atoms in the fir st 3 electronic states ($H(n)$)\, and ground state ions ($H^+$ \, $H_2^+$ \, $H_3^+$ and $H^−$) and a comprehensive set of surface and volume chem ical reactions.\nIn addition\, the global model includes boundary conditio ns for multi-aperture extraction system. We validate our model by comparin g simulation results for a plasma composition and species temperatures in the negative hydrogen ion source developed at IPP Garching.\n\n\n\nThis wo rk was performed under the auspices of the Department of Energy\, Office o f Basic Energy Sciences Award #DE-SC0009585.\n\nhttps://indico.inp.nsk.su/ event/11/contributions/349/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/349/ END:VEVENT BEGIN:VEVENT SUMMARY:Negative Hydrogen ion density measurement in a permanent magnet ba sed Helicon Ion source (HELEN-I) using cavity ring down spectroscopic tech nique DTSTART;VALUE=DATE-TIME:20180907T050000Z DTEND;VALUE=DATE-TIME:20180907T053000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-350@indico.inp.nsk.su DESCRIPTION:Speakers: Debrup Mukhopadhyay (Institute for Plasma Research)\ nNegative ion source based neutral beam injection system is one of the mos t efficient method of fusion plasma heating. Negative ion source is used i nstead of positive ions in case of higher power NBIs\,due to high neutrali zation factor in the beam energy range useful for ITER type fusion reactor s.To understand the efficiency of negative ion source\, negative ion densi ty measurement is a prerequisite. In the present work\, a highly sensitive cavity ring down spectroscopy(CRDS) system has been developed and employe d in a in house developed permanent magnet based Helicon plasma source (H ELEN-I) operated in volume production mode\, to measure the line integrate d negative ion density in it. The present CRDS system uses a Nd-YAG laser of wavelength 1064 nm. A stable optical cavity is created by using highly reflecting mirrors of reflectivity ~99.99%. The stable cavity is part of t he plasma chamber and is created in such a way that hydrogen plasma is pre sent within the cavity volume. When the laser enters the cavity through th e first mirror\, it suffers multiple reflections on the inner surfaces of the cavity mirrors and therefore passes through the plasma volume multiple times.The transmitted intensity through the second mirror is measured wit h a photo detector. During the travel time (~100 microsec)\, the laser pho ton photo detach the loosely bound electrons from negative hydrogen ions i n the plasma volume within the line of sight of the laser beam. As a resul t\, the laser pulse intensity goes down exponentially with time. The chara cteristic of the temporal decay of the laser pulse intensity\,known as rin g down time(RDT) is a function of line of sight integrated negative ion de nsity. The experimental result of the negative ion density measurement by CRDS system for different working pressure\, axial magnetic field and RF ( 13.56 MHz) power are discussed. It is seen that at high power range (800-9 50 Watt)\, when the plasma source is working in Helicon(w) mode\, having p lasma density of order of 10^18 per meter cube and a plasma temperature of ~2 eV. The corresponding line integrated negative ion density of ~10^16 p er meter cube in volume mode without any application of transverse filter magnetic field.\n\nhttps://indico.inp.nsk.su/event/11/contributions/350/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/350/ END:VEVENT BEGIN:VEVENT SUMMARY:Modelling of beam transport and interactions with beamline compone nts in the CFETR neutral beam test facility DTSTART;VALUE=DATE-TIME:20180907T030000Z DTEND;VALUE=DATE-TIME:20180907T032500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-351@indico.inp.nsk.su DESCRIPTION:Speakers: Jianglong Wei (Institute of Plasma Physics\, Chinese Academy of Sciences)\nThe neutral beam injection (NBI) will be a fundamen tal method for plasma heating and current drive in the China Fusion Engine ering Test Reactor (CFETR). As the most critical step towards the CFETR-NB I system\, a research project of the CFETR neutral beam test facility (CFE TR-NBTF) has be started in China. The objectives of the first phase of CFE TR-NBTF are to produce a negative hydrogen ion beam of >20A up to 200kV fo r 3600s and to attain a neutralization efficiency of >50%\, thus a neutral beam power of >2MW is foreseen onto the calorimeter. A full-comprehensive model has been developed in the COMSOL environment to optimize the physic al design of the CFETR-NBTF beamline system\, in terms of the gas distribu tion\, the beam neutralization\, the beam separation\, and the power depos ition onto the beamline components. This model can calculate the particle motion in electromagnetic fields\, including not only the primary beam\, b ut also the co-extracted electrons and the secondary particles. The prelim inary results reported here are focused on the neutralization of negative ion beam in different gas inflow and the power deposition of different par ticles on the residual ion dump due to electrical separation.\n\nhttps://i ndico.inp.nsk.su/event/11/contributions/351/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/351/ END:VEVENT BEGIN:VEVENT SUMMARY:Electromagnetic and thermal analyses of Faraday shield of various materials and structures for a ICP source DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-352@indico.inp.nsk.su DESCRIPTION:Speakers: Peng Chen (State Key Laboratory of Advanced Electrom agnetic Engineering and Technology\, Huazhong University of Science and Te chnology)\nFaraday shield (FS)\, a thin-wall metal structure with slits\, is used in inductive coupled plasma (ICP) sources to protect the ceramic t ube from the plasma erosion and eliminate capacitive coupling. Through the slit\, electromagnetic energy is coupled into the driver to excite and su stain plasma\, hence FS is an important component of ICP source. Material and structure\, which has significant effect on the distribution of electr omagnetic field inside the driver and temperature distribution on FS\, is a critical issue for FS. \nIn this contribution\, influence of Faraday shi eld of various materials and structures on electromagnetic and thermal per formance is discussed. FS made of copper\, aluminum\, molybdenum and stain less steel\, as well as FS of different geometry\, different size and diff erent number of silts\, are investigated. Electromagnetic field\, RF power loss and temperature distribution of different FS is compared according t o numerical simulations of a 3D actual source. This work can be used as a reference for the design of Faraday shield.\n\nhttps://indico.inp.nsk.su/e vent/11/contributions/352/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/352/ END:VEVENT BEGIN:VEVENT SUMMARY:Modelling and optimization of neutral beam injectors for fusion ne utron source "DEMO-FNS" DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-353@indico.inp.nsk.su DESCRIPTION:Speakers: Sergey Ananyev (NRC "Kurchatov Institute")\nNeutral beam injection (NBI) system of the thermonuclear neutron source DEMO-FNS i s suggested for a steady-state plasma heating and current drive. The injec tor scheme for DEMO-FNS incorporates a negative ions source coupled with a ccelerator delivering D- beam accelerated to 500keV with the current 40A. The subsequent neutralization and ions removal from the beam\, as well as its further path to plasma lead to a significant distance between beam sou rce and injection point (~20 m). An effective beam transmission to such a long distance with minimum losses is a real challenge\, requiring a detail ed 3D-modelling of the beam and a beamline structure optimization. The sim ulation includes minimization of beam losses due to direct interception an d reasonable reduction of beam particles loss due to reionization. The opt imization problem has proved to include a large amount of parameters\, con straints\, and it is rather sensitive to small deviations of input data\, therefore the models should be fine-tuned and allow for high accuracy esti mations. \nThe most important conditions affecting the injector performanc e\, constraints and operation scenarios are discussed in this report\, as well as the performance criteria for the baseline (assumed) configuration. The NBI system for DEMO-FNS is simulated by beam tracing codes – PDP an d BTR\, both developed earlier and verified for the ITER project. Optimal geometry searching methodology and the investigation results of various NB I operation modes are presented. An optimal self-consistent injector confi guration and the initial ion beam are chosen. Brief the evolution of the b eam power profile and total losses\, detailed load distributions for all e lements of the NBI are calculated.\n\nhttps://indico.inp.nsk.su/event/11/c ontributions/353/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/353/ END:VEVENT BEGIN:VEVENT SUMMARY:Beam steering characteristics of ferromagnetic electrode DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-354@indico.inp.nsk.su DESCRIPTION:Speakers: Haruhisa Nakano (National Institute for Fusion Scien ce)\nIn hydrogen negative ion sources\, co-extracted electrons are dumped on extraction grid (EG) with electron deflection magnets (EDMs). The negat ive ion beam trajectory is slightly perturbed by the EDM field\, and the a perture displacement technique has been applied in negative ion sources fo r fusion in order to compensate the beam deflection [1]. Recently\, it was proposed that the beam deflection can be intrinsically cancelled by the a symmetric EDM field [2]. In this concept\, the asymmetric field is formed by the combination of the conventional EDMs and additional set of permanen t magnets.\n\nIn this study\, a ferromagnetic steering grid (SG) was used as an alternative way to realize the asymmetric EDM field. The beam accele ration experiments were carried out in the NIFS R&D negative ion source (N IFS-RNIS)\, and the beam footprint was measured with a beamlet monitor sys tem consisting of an infrared camera and 1D carbon fiber composite (CFC) t iles at various operational conditions. Analysis of the beam trajectory is being carried out with OPERA-3d code. In the presentation\, we will discu ss the beam steering characteristics of the ferromagnetic SG.\n\nReference s\n\n[1] M. Hamabe et al.\, Rev. Sci. Instrum. 72\, 3237 (2001).\n\n[2] G. Chitarin et al.\, Rev. Sci. Instrum. 85\, 02B317 (2014).\n\nhttps://indic o.inp.nsk.su/event/11/contributions/354/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/354/ END:VEVENT BEGIN:VEVENT SUMMARY:Concept of plasma heating and current drive neutral beam system fo r fusion neutron source "DEMO-FNS" DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-355@indico.inp.nsk.su DESCRIPTION:Speakers: Sergey Ananyev (NRC "Kurchatov Institute")\nSteady-s tate operation of a fusion neutron source (FNS) requires plasma heating an d current drive by means of additional power delivered by neutral beams. S ix neutral beam injectors (NBI) will provide DEMO-FNS machine with additio nal heating power up to 30 MW\, with neutral particle energy 500 keV. NBI systems developed for ITER can serve as the prototype for DEMO-FNS\, as bo th systems have similar ion source current\, with accelerated beam power i n ITER NBI (1MeV) being twice as large as in DEMO-FNS. The paper describes the NBI system with account of its integration to DEMO-FNS tokamak comple x. Significant differences in the design elements of injectors for DEMO-FN S are associated with smaller values of critical parameters such as inject ed power\, the values of peak power densities on the walls along the beam path\, smaller gas flows in the injector compared to the injectors being d eveloped for ITER. At this stage\, we deliberately do not consider systems that are auxiliary to the injection complex of fast atoms\, but we emphas ize the complexity of their design and integration into tokamak systems. W e proposed the ITER NBI parameters revision to optimize the design of the injector and its components for the DEMO-FNS facility. Optimal beam transm ission line configuration has been chosen and the loads on its elements ha ve been calculated.\n\nhttps://indico.inp.nsk.su/event/11/contributions/35 5/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/355/ END:VEVENT BEGIN:VEVENT SUMMARY:Carbon Film in Radio Frequency Surface Plasma Source with Cesiatio n DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-356@indico.inp.nsk.su DESCRIPTION:Speakers: Vadim Dudnikov (Muons\, Inc)\nIt is assumed that per sistent cesiation in the SNS RF SPS is related to deposition of carbon fil m on the collar converter. The work function dependence for graphite with alkali deposition has no minimum typical for metals and semiconductors and the final work function is higher. For this reason\, the probability of H - secondary emission from cesiated metal and semiconductors can be higher than from cesiated carbon films but the carbon film maintains cesiation lo nger and can operate with low cesium consumption.\n\nhttps://indico.inp.ns k.su/event/11/contributions/356/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/356/ END:VEVENT BEGIN:VEVENT SUMMARY:Langmuir probe analysis in negative ion beams DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-357@indico.inp.nsk.su DESCRIPTION:Speakers: Emanuele Sartori (Consorzio RFX - Università degli Studi di Padova)\nNegative ion beams are used as precursors of neutral bea ms for additional heating of fusion plasmas. By ionizing the background ga s\, positive ions are confined and cumulated in the negative potential wel l of the ion beam\, until the space charge is neutralized and the negative ion beam can propagate in the absence of defocusing electric fields. Expe rimental measurements of the negative ion beam plasma parameters can provi de essential data for the beam neutralization in gas and plasma neutralize rs. This paper presents a method to analyse Lagnmuir probe data obtained i n a negative ion beam\, in which the beam ion current dominates on the cur rent given by the secondary ion and electron plasma. The sheath model is d iscussed for different compensation degrees of the beam space charge\, als o including the secondary electron emission form the surface. The analytic al curves are fitted to experimental data by adjusting the plasma paramete rs. Plasma potentials along a profile transverse to the beam axis are dedu ced from the probe data.\n\nhttps://indico.inp.nsk.su/event/11/contributio ns/357/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/357/ END:VEVENT BEGIN:VEVENT SUMMARY:Progress of the J-PARC cesiated rf-driven negative hydrogen ion so urce DTSTART;VALUE=DATE-TIME:20180904T020000Z DTEND;VALUE=DATE-TIME:20180904T022500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-379@indico.inp.nsk.su DESCRIPTION:Speakers: Katsuhiro Shinto (J-PARC)\nOperation of a cesiated r f-driven negative hydrogen ion (H$^-$) source was initiated in September 2 014 in order to fulfill the requirements on beam current upgrade in J-PARC (Japan Proton Accelerator Research Complex). The required H$^-$ beam curr ent from the ion source to the J-PARC accelerators has been successfully d elivered without serious problems. In 2017-2018 campaign\, continuous oper ation of the ion source for 2\,080 hours from January to March 2018 was ac hieved with the beam current of 45 mA extracted from the source. We are co nducting an endurance test of a J-PARC prototype antenna at a test bench. Approximately 1\,000-hour operation with the prototype antenna was success fully performed. We will present the progress of the ion source as well as the prototype antenna test.\n\nhttps://indico.inp.nsk.su/event/11/contrib utions/379/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/379/ END:VEVENT BEGIN:VEVENT SUMMARY:High Voltage Negative Ion Beam Injector for Tandem Accelerator DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-359@indico.inp.nsk.su DESCRIPTION:Speakers: Andrey Sanin (Budker Institute of Nuclear Physics)\n An electrostatic vacuum-insulation tandem accelerator is under operation a t Budker Institute of Nuclear Physics since 2006. The 2 -2.5 MeV protons w ith continuous accelerated current more than 5 mA are produced [1]. To inc rease the injected current\, the new injector with pre-acceleration of neg ative ions was developed. The injector consists of the high current negati ve ion source version [2]\, of bending magnet\, and of pre-accelerator. Th e bending magnet made of permanent magnet segments with correction coils p rovides the negative ion beam focusing and separation from the concomitant fluxes of electrons\, heavy ions and neutrals. The pre-accelerating tube is designed to accelerate the beam up to energy of 150 keV. The source and its subsystems are installed at the high-voltage platform. The descriptio n of new injector and first results on 15 mA negative ion beam production\ , transport and acceleration will be discussed.\n\n\n[1] A. A. Ivanov\, D. Kasatov\, A. Koshkarev et al. “Obtaining a Proton Beam with 5-mA Curren t in a Tandem Accelerator with Vacuum Insulation”\, Technical Physics Le tters\, 42\, p. 607 (2016). DOI: 10.1134/S1063785016060225.\n \n[2] Yu. Be lchenko\, A. Sanin\, and A. Ivanov\, “15 mA CW H- Source for Accelerator s”. AIP Conference Proceedings 1097\, 214 (2009).\n\nhttps://indico.inp. nsk.su/event/11/contributions/359/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/359/ END:VEVENT BEGIN:VEVENT SUMMARY:Development of OPPIS Ion Source for Polarized Negative Ion Beam Pr oduction. DTSTART;VALUE=DATE-TIME:20180905T093000Z DTEND;VALUE=DATE-TIME:20180905T095500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-360@indico.inp.nsk.su DESCRIPTION:Speakers: Anton Kolmogorov (Budker Institute of Nuclear Physic s)\nThe polarized beam for RHIC spin physics experimental program is produ ced in the Optically Pumped Polarized H– Ion Source (OPPIS). The present RHIC OPPIS produces 0.5–1.0 mA current in 300 μs pulse duration. The p olarized H– ion beam of 35 keV beam energy out of the source is accelera ted to 200 MeV in a linear accelerator for strip injection to Booster. The H– ion pulse is captured in a single Booster bunch\, which is accelerat ed in the Booster and then transferred to the AGS\, which is accelerated t o 24.3 GeV for injection to RHIC.\n\nThe RHIC polarized H– ion source ha d been upgraded to higher intensity and polarization by using a very high brightness fast atomic beam injector developed at BINP\, Novosibirsk. In t his injector the proton beam is extracted by a four-grid multi-aperture io n optical system and neutralized in the H2 gas cell downstream from the gr ids. The proton beam is extracted from plasma emitter with a low transvers e ion temperature of ~0.2 eV which is formed by plasma jet expansion from the arc plasma generator. The multi-hole grids are spherically shaped to p roduce “geometrical” beam focusing. The atoms of the beam formed by th e injector get into a strong magnetic field\, where they lose the electron in the helium target\, and then they capture the polarized electron in th e target of rubidium vapor. The transfer of the spin projection from the e lectron to the nucleus of the atom occurs in the region of Sona transition at the exit from the magnetic field. Negative hydrogen ion beam is formed when electrons are captured by the atoms of a polarized beam in a station ary recirculating sodium vapor target.\n\nEffective transportation of nonp olarized negative hydrogen ions formed during charge exchange of a high-br ightness proton beam with ballistic focusing in a hydrogen charge-exchange target was observed in experiment. A beam of protons with an energy of 10 keV\, a current of 4.7 A\, an emission current density of 470 mA/cm2\, an angular divergence of 10 mrad\, and a focal length of 200 cm was formed a t 1 Hz frequency in the fast atomic beam injector. The value of H– ion c urrent passing through a 2 cm diaphragm located at a distance of 200 cm fr om the emitter was 75 mA.\n\nhttps://indico.inp.nsk.su/event/11/contributi ons/360/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/360/ END:VEVENT BEGIN:VEVENT SUMMARY:Plasma characterization of a Hall Effect Thruster for a Negative I on Source concept DTSTART;VALUE=DATE-TIME:20180907T043000Z DTEND;VALUE=DATE-TIME:20180907T045500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-361@indico.inp.nsk.su DESCRIPTION:Speakers: Emanuele Sartori (Consorzio RFX)\nNegative ion sourc es are a key component of neutral beam injection systems. A novel concept for a negative ion source based on existing well tested Hall thrusters (HT ) is presented. The thruster has been designed in order to maximize the hy drogen dissociation process so that the atom flux which exits the thruster has an optimized energy to generate negative ions when impinging on a low work function surface. The novel concept can in principle offer several a dvantages\, for instance a limited amount of co-extracted electrons\, a mo re uniform generation of negative ions and a lower rate of destruction of negative ions. The thruster has been completed and is now in operation. In this contribution\, the behavior of the thruster with different mass flow rate and voltage is presented. In particular\, the first measurements of the plume plasma parameters by a Langmuir probe are shown\, both with Nitr ogen and Hydrogen as injected gas. The spatial profile of the plasma elect ronic temperature and density have been obtained by scanning the region ou tside the exit plane of the thruster. The measurements are aimed to determ ine the best position of a caesiated sample in order to maximize the gener ation of the negative Hydrogen ions.\n\nhttps://indico.inp.nsk.su/event/11 /contributions/361/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/361/ END:VEVENT BEGIN:VEVENT SUMMARY:Operating Experience and Recent Updates of Negative Hydrogen Ion S ource at BINP Tandem Accelerator DTSTART;VALUE=DATE-TIME:20180905T050000Z DTEND;VALUE=DATE-TIME:20180905T052500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-362@indico.inp.nsk.su DESCRIPTION:Speakers: Andrey Sanin (Budker Institute of Nuclear Physics)\n A continuous-wave surface-plasma negative hydrogen ion source is used at 2 MeV tandem accelerator with vacuum insulation at the Budker Institute of nuclear physics since 2006 [1]. The source uses the hydrogen-cesium Pennin g discharge with plasma injection from hollow cathodes\, and negative hydr ogen ion production due to interaction of plasma particles with anode elec trode surface [2]. It routinely produces dc H- beam in the range 1 ÷ 9 mA in daily runs with accelerated proton beam delivery to the lithium target of BNCT experimental device. Source parameters and maintenance statistics during long-term operation will be discussed. Recent upgrades\, made for increasing beam current production and transport will be presented as well .\n\n[1] A. Kudryavtsev\, Yu. Belchenko\, A. Burdakov et al. Rev. Sci. Ins trum.\, 79\, 02C709 (2008).\n\n[2] Yu. Belchenko\, A. Sanin\, I. Gusev et al.\, Rev. Sci. Instrum.\, 79\, 02A521 (2008).\n\nhttps://indico.inp.nsk.s u/event/11/contributions/362/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/362/ END:VEVENT BEGIN:VEVENT SUMMARY:Study of caesium-wall interaction parameters within a hydrogen pla sma DTSTART;VALUE=DATE-TIME:20180905T023000Z DTEND;VALUE=DATE-TIME:20180905T025500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-363@indico.inp.nsk.su DESCRIPTION:Speakers: Emanuele Sartori (Consorzio RFX - Università di Pad ova)\nUnderstanding the distribution of caesium by plasma within the expan sion region of the SPIDER beam source is essential to maximise the efficie ncy of negative ion surface-production. The caesium is redistributed by pl asma diffusion and is greatly affected by the plasma-wall interactions wit h the molybdenum walls. This work considers the processes which make up th e plasma wall interaction and the transmission of generated particles acro ss the plasma sheath. \nAn analytic model is set-up for each of the four m ain processes that occur at the wall: thermal desorption (evaporation)\, p hysical desorption (sputtering)\, backscattering and adsorption\, with the latter being most significant. These processes occur in response not only to the wall temperature but also to the influx of particles to the wall\, and generate atoms/ions outwards to the plasma bulk which must first cros s the collisional plasma sheath and pre-sheath. The probability of re-ente ring the bulk is measured by a transmission factor\, which is calculated s pecifically for each charge state and process\, as it considers the energi es at which the process occurs. The transmission factor considers the mean free path of ionising collisions\, along with comparing the potential and kinetic energy of each ion with the threshold energy to leave the sheath. The combination of the probability of transmission and the fluxes generat ed at the wall allows for the study of the redistribution from the plasma discharge within the beam source.\n\nhttps://indico.inp.nsk.su/event/11/co ntributions/363/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/363/ END:VEVENT BEGIN:VEVENT SUMMARY:Improving the transported negative ion beam current in NIO1 DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-364@indico.inp.nsk.su DESCRIPTION:Speakers: Emanuele Sartori (Consorzio RFX - Università di Pad ova)\nIn order to reduce the beam losses of the negative ion beam in the N IO1 experiment\, the vacuum system was improved by installing an additiona l cryogenic pump. In the upgraded configuration\, the negative ion beam ca n be operated in two regimes of high and low background pressures. The gas flow in the improved configuration was simulated\, characterizing the exi sting pumping system and verifying the best configuration for the improved pumping scheme. The charge state of the negative ion beam moving through the background hydrogen gas is calculated\, thus providing the stripping l osses inside the accelerator and in the transport region. The expected val ues are compared with the experimental data obtained with a diagnostic bea m dump\, a one-dimensional carbon fiber calorimeter\, and other beam-plasm a diagnostics measuring the parameters of the secondary plasma. The collec ted electric current and the heat flux reconstructed from thermal measurem ents are compared with the expected beam particle flux. The measurements i ndicate as expected an increase of negative ion current at full accelerati on and a decrease of the plasma electron contribution.\n\nhttps://indico.i np.nsk.su/event/11/contributions/364/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/364/ END:VEVENT BEGIN:VEVENT SUMMARY:Start of SPIDER operation towards ITER Neutral Beams DTSTART;VALUE=DATE-TIME:20180903T031000Z DTEND;VALUE=DATE-TIME:20180903T034000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-365@indico.inp.nsk.su DESCRIPTION:Speakers: Giuseppe Chitarin (Consorzio RFX)\nTo reach fusion c onditions and control plasma configuration in ITER\, the next step towards establishing nuclear fusion as viable energy source\, suitable combinatio n of additional heating and current drive systems is necessary. Among them \, two Neutral Beam Injectors (NBI) will provide 33MW hydrogen/deuterium p articles electrostatically accelerated to 1MeV\; efficient gas-cell neutra lisation at such beam energy requires negative ions\, obtained by caesium- catalysed surface conversion of hydrogen/deuterium atoms in the ion source . ITER NBI requirements have never been simultaneously attained\; so a Neu tral Beam Test Facility (NBTF) was set up at Consorzio RFX (Italy). Experi ments will verify continuous NBI operation for one hour\, under stringent requirements for beam divergence (\n\nhttps://indico.inp.nsk.su/event/11/c ontributions/365/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/365/ END:VEVENT BEGIN:VEVENT SUMMARY:Polarized negative ion source with multiply sphericaly focusing su rface plasma ionizer DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-366@indico.inp.nsk.su DESCRIPTION:Speakers: Vadim Dudnikov (Muons\, Inc)\nIt is proposed one uni versal H-/D- ion source design combining the most advanced developments in the field of polarized ion sources to provide high-current high-brightnes s ion beams with >90% polarization and improved lifetime\, reliability\, a nd power efficiency. The new source utilizes high-intensity resonant charg e-exchange ionization of neutral atoms by negative ions generated by cesia ted surface-plasma interactions via a multi-spherical negative ion focusin g element. Multi-spherical focusing of the negative ions strongly suppres ses the parasitic generation of unpolarized H-/D- ions. By incorporating new and novel designs for the dissociator and plasma generator in parallel with the multi-spherical focusing the design can suppress adsorption and depolarization of particles from the polarized beam greatly improving perf ormance over current concepts.\n\nhttps://indico.inp.nsk.su/event/11/contr ibutions/366/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/366/ END:VEVENT BEGIN:VEVENT SUMMARY:Influence of External Magnets and the Potential Rods on the Plasma Symmetry in the ELISE Ion Source DTSTART;VALUE=DATE-TIME:20180903T044000Z DTEND;VALUE=DATE-TIME:20180903T050500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-367@indico.inp.nsk.su DESCRIPTION:Speakers: Christian Wimmer (Max-Planck-Institut für Plasmaphy sik)\nThe Neutral Beam Injection (NBI) system for ITER requires large scal e sources for negative hydrogen ions. The ELISE test facility at IPP Garch ing uses a ½ scale ITER-source (extraction area of 0.1 m$^2$ at ELISE) an d shall demonstrate the feasibility of the ITER parameters (extracted $j_\ \mathrm{H^-} = 329~ \\mathrm{A/m^2}$ for 1000 s\, $j_\\mathrm{D^-} = 286~\ \mathrm{A/m^2}$ for 3600 s\, with a co-extracted electron current below th e ion current at a source filling pressure of below 0.3 Pa). In long pulse s the co-extracted electron current density $j_\\mathrm{e}$ is strongly in creasing and usually limits the source performance. Two measures for stabi lizing and lowering $j_\\mathrm{e}$ have been applied at ELISE in the past : on the one hand adding bars of permanent magnets outside of the source s trengthening the magnetic filter field and on the other hand the installat ion of potential rods perpendicular to the magnetic field lines close to t he extraction system. Since $\\mathbf{F} \\times \\mathbf{B}$ drifts lead to a vertically asymmetric plasma\, an influence of both measures on the p lasma symmetry is expected by modifying the magnetic field or electric pot ential topology in the source. The plasma asymmetry is a crucial parameter \, since it may lead to an inhomogeneous beam under certain conditions. Th e change of the plasma symmetry close to the extraction system\, determine d by two double probes\, is presented.\n\nhttps://indico.inp.nsk.su/event/ 11/contributions/367/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/367/ END:VEVENT BEGIN:VEVENT SUMMARY:Spectroscopic Investigations of the Ion Source at BATMAN Upgrade DTSTART;VALUE=DATE-TIME:20180904T071000Z DTEND;VALUE=DATE-TIME:20180904T073500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-368@indico.inp.nsk.su DESCRIPTION:Speakers: Ursel Fantz (Max-Planck-Institut für Plasmaphysik)\ nAt the BATMAN test facility\, prototypes of RF driven sources of negative hydrogen ions for neutral beam heating systems have been developed succes sfully over the last decades. Recently\, the test facility has been upgrad ed with a new ITER-like extraction system comparable in size to one ITER b eamlet group. Like for the ITER sources\, the magnetic filter field can no w also be generated by a current flowing through the plasma grid with the option to use dedicatedly the permanent magnets embedded into a diagnostic flange or in an external magnet frame as in the previous BATMAN setup. In addition\, the diagnostic access to the ion source plasma was improved. T ogether with an enhanced spectroscopic system\, this offers the unique pos sibility to study the plasma parameters and their dependence on the magnet ic filter field by emission spectroscopy more thoroughly. \n \nThe OES measurements were carried out with a high resolution spectrometer (FWHM ≈ 16 pm @ 600 nm) at three different lines of sight: one going in axial direction through the cylindrical ion source driver\, one in horizontal di rection through the expansion volume and one in the same direction but clo se to the plasma grid. Plasma parameters are obtained from the measured em issivities of the atomic Balmer series and the molecular Fulcher-transitio n via applying the collisional radiative models Yacora H and H2. In additi on\, a refined evaluation procedure is used for investigating the rovibrat ional population of the hydrogen molecule allowing for a more accurate det ermination of the gas temperature. This is of particular relevance for cal culation of the gas pressure profile in the extraction system\, which is r equired for the determination of the H– stripping losses in this region. \n\nhttps://indico.inp.nsk.su/event/11/contributions/368/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/368/ END:VEVENT BEGIN:VEVENT SUMMARY:Long Pulse Operation at ELISE: Approaching the ITER Parameters DTSTART;VALUE=DATE-TIME:20180903T041000Z DTEND;VALUE=DATE-TIME:20180903T043500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-369@indico.inp.nsk.su DESCRIPTION:Speakers: Dirk Wünderlich (Max-Planck-Institut für Plasmaphy sik)\nThe ion source of the ELISE test facility ($0.9×1.0 \\\,\\mathrm{m} ^2$ with an extraction area of $0.1 \\\,\\mathrm{m}^2$) has half the size of the ion source foreseen for the ITER NBI beam lines. Main aim of ELISE is to demonstrate that such large RF driven negative ion sources can achie ve the following parameters at a filling pressure of $0.3 \\\,\\mathrm{Pa} $: extracted current densities of $28.5 \\\, \\mathrm{mA}/\\mathrm{cm}^2$ in deuterium for a pulse length of $3600 \\\,\\mathrm{s}$ and $33.0 \\\, \ \mathrm{mA}/\\mathrm{cm}^2$ in hydrogen for $1000 \\\, \\mathrm{s}$\, a ra tio of co-extracted electrons to extracted ions below one and deviations i n the uniformity of the extracted beam of less than $10 \\\, \\%$.\n\nThis presentation describes results of the recent ELISE experimental campaigns in hydrogen and deuterium. Focus is laid on long pulse operation (up to t he pulse length required for ITER) with high RF power (possible are up to 75 kW/driver). The performance obtained during such pulses is restricted m ainly by a strong temporal increase of the co-extracted electrons. Additio nally\, the co-extracted electron current can show a pronounced top-bottom asymmetry. For SPIDER and MITICA as well as for the ITER NBI system the l atter can pose a risk to the extraction grid (EG)\, acting as a dump for t hese electrons: even when the measured global amount of co-extracted elect rons is below the limit\, a strong asymmetry can result in local overheati ng of the EG.\n\nSeveral measures for reducing\, stabilizing and symmetriz ing the co-extracted electron current while not reducing significantly the extracted negative ion current have been investigated systematically. Exa mples are modifying the electrostatic potentials close to the extraction s ystem by means of elements additionally introduced into the source and mod ifying the temperatures of different ion source components. \n\nPresented and discussed are extracted negative ions and co-extracted electron curren t densities obtained during these investigations as well as results of pla sma and beam diagnostics (indicating the plasma parameters and their homog eneity and the beam homogeneity\, respectively).\n\nhttps://indico.inp.nsk .su/event/11/contributions/369/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/369/ END:VEVENT BEGIN:VEVENT SUMMARY:Role of angular orientation of dipoles on work function during cae sium deposition on a metal surface – a phenomenological model DTSTART;VALUE=DATE-TIME:20180906T040000Z DTEND;VALUE=DATE-TIME:20180906T042500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-370@indico.inp.nsk.su DESCRIPTION:Speakers: Pranjal Singh (Institute for Plasma Research)\nIt ha s been experimentally proven that adsorption of alkali metals like Caesium (Cs) on tungsten reduces tungsten’s effective work function. The work f unction of pure W surface is 4.55eV and that of pure Cs is 2.14 eV [1]\; h owever with fractional monolayer (0.6 – 0.7) of Cs coverage on W surface makes the effective work-function of the W surface as low as 1.5eV [2]. I t is well known from previous experiments that chemisorption of foreign at oms on metal surfaces give rise to a strong double-layer. This may be posi tive outwards or negative outwards according to the nature of adsorbed ato ms. The ionization potential of Cs (3.85 eV) is smaller than the work fun ction of polycrystalline tungsten (4.5 eV). Consequently\, the electroposi tive Cs will give up its valence electron to the metal\, forming an electr ical double layer with positive outwards and hence reducing the effective work function. The theory of adsorbate-induced work function change (WFC)\ , is to a large extent based on the classical dipole model given by Langmu ir [3]\, which had been further modified by Miller\, by a simple point dip ole depolarization model [4]. However\, this experimentally observed anoma lous variation of work function during Caesiation has not been explained b efore using classical model for the full fractional range of monolayer for mation (0≤Ѳ≤1). In the present work\, it is shown analytically that t he orientation of dipoles in the classical model indeed plays a significan t role and explains the experimental trend of anomalous variation of work function. Fractional monolayer can be achieved by time-varying controlled deposition of Cs atoms on a metal surface.\n\nThe existing classical model is based on a 2-D square lattice of parallel point dipoles with an axis p erpendicular to the line joining them. At a low coverage of adatoms\, surf ace dipoles are non-interacting owing to which they tend to form an array of dipoles\, all identically normal to the surface. However\, at high cove rage(ϴ>.5) in addition to the point depolarization\, we propose that the repulsive interaction among the neighboring dipoles due to their closeness may lead to change in the orientation of the dipoles. Thus by including a n effective angular orientation factor (AOF) of mutually interacting dipol es\, we have made an analytical approach to extend the existing classical model. This phenomenological simple model reasonably explains the experime ntal results of anomalous variation of work function during Cs deposition on W surface. \n\n\nReferences\n\n[1] Herbert B. Michaelson. IBM Corporat ion\, Armonk. New York 10504 (1977).\n\n[2] V.M. Gavrilyuk\, A.G. Naumovet s\, A.G. Fedorus\, Soviet Phys.-JETP\, 24 (1967).\n\n[3] J.B. Taylor\, I. Langmuir\, Phys. Rev. 44\, 423 (1933).\n\n[4] A. R. Miller\, Proc. Cambrid ge Philos. Soc. 42\, 292 (1946).\n\nhttps://indico.inp.nsk.su/event/11/con tributions/370/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/370/ END:VEVENT BEGIN:VEVENT SUMMARY:A plasma target for neutralization of the negative ion beam DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-371@indico.inp.nsk.su DESCRIPTION:Speakers: Ivan Emelev (Budker Institute of Nuclear Physics)\nT he results of the experimental study of confinement of low-temperature pla sma target for neutralization of high-energy negative ion beam are present ed in the paper. \n\nThe plasma target cylindrical vacuum chamber is 1.2 m long and 0.2 m in diameter. The axisymmetric multicusp magnetic field is formed at the periphery of the target chamber by using an array of the per manent NdFeB magnets\, which are placed closely on the thin chamber walls. The target chamber is ended by the two diaphragms with the two 0.1 m diam eter apertures for the negative ion beam passing through. For reduction of the plasma losses through the ends\, the inverse magnetic field are forme d in the apertures [1].\n\nThe plasma is produced in the target by ionizat ion of the working gas by electrons\, which emitted by six plane LaB$_6$ c athode\, which are placed uniformly over azimuth at the center of the plas ma target near the wall. The plasma parameters were defined from Langmuir probes measurements and from recharging of diagnostic atomic beam. In shor t pulses at 200 kW power\, the hydrogen plasma with density n$_i$ ≈ 2∙ 10$^{13}$ cm$^{-3}$ is produced. Degree of plasma ionization reaches 50 %. \n\n\n\n1. G.I. Dimov\, A.V. Ivanov\, Fusion Science and Technology\, 2013 \, v.63\, issue 1T\, p.111-114.\n\nhttps://indico.inp.nsk.su/event/11/cont ributions/371/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/371/ END:VEVENT BEGIN:VEVENT SUMMARY:Development of Radio frequency based negative ion source test bed DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-372@indico.inp.nsk.su DESCRIPTION:Speakers: Chundong Hu (Institute of Plasma Physics\, Chinese A cademy of Sciences)\nNeutral beam injector (NBI) is an effective plasma he ating and driving method for fusion sciences research. The China Fusion En gineering Test Reactor (CFETR) is under design and will be developed in th e near future. In order to support the development of CFETR\, a negative i on based neutral beam injector was under design. The ion source is the mos t precision and important part of NBI. A negative ion source test bed was developed in the Institute of Plasma Physics\, Chinese Academy of Science s (ASIPP). \n\nThe negative ion source test bed contains of two 1MHz RF fr equency power with 50 kW and 100kW respectively\, a dummy load\, a bias po wer supply and an ion extraction power supply (16kV @ 20A)\, a matching un it with high voltage transformer\, a vacuum chamber\, gas inlet system ang gas pumping system\, which is shown in Fig.1. Several diagnostic tools wa s employed for the plamsa parameters measurement\, such as the Langmuir pr obe\, the microwave interferometer\, the optical emission spectrometer (OE S)\, cavity ring-down spectroscopy system (CRDS)\, the thermocouple system (TC) and water flow calorimeter system (WFC). \n\nThe negative ion sourc e was designed and tested on the test bed. It contains the RF based plasma generator and negative ion accelerator. There are several types of RF pla sma generator developed\, such as single driver source\, double source and larger area driver source. The negative ion accelertor was design and pre limary tested too. The details of the negative ion source test bed and the experimental results of RF plasma generator and the negative ion beam ext raction will be presented.\n\nhttps://indico.inp.nsk.su/event/11/contribut ions/372/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/372/ END:VEVENT BEGIN:VEVENT SUMMARY:Uniformity of the Large Beam of ELISE during Cs Conditioning DTSTART;VALUE=DATE-TIME:20180905T020000Z DTEND;VALUE=DATE-TIME:20180905T022500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-373@indico.inp.nsk.su DESCRIPTION:Speakers: Federica Bonomo (Max-Planck-Institut für Plasmaphys ik)\nThe modular concept of the ITER Negative Beam Ion (NBI) source has be en replicated in the ELISE test facility with half of the source size in t he vertical direction\; thus producing a large beam of about $1\\\,m\\\,× \\\,1\\\,m$. The target of ELISE is to achieve simultaneously the ITER NBI parameters in terms of negative ion extracted current (in H and D)\, puls e duration and ratio of co-extracted electrons below $1$ at a source filli ng pressure of $0.3$ Pa. Due to limitations of the HV power supply\, only 10 s of beam extraction about every $150\\\,$s can be applied\, with a max imum total voltage of $60$ kV. This implies that ITER relevant beam diverg ences cannot be achieved\; however\, trends and behavior of the beam diver gence in ELISE as well as beam uniformity are of great importance for ITER . The beam in ELISE is characterized by means of various diagnostics: the currents in the grid system are electrically measured and provide the tota l extracted negative ion current as well as information of the beam losses separately measured in the two segments of the extraction and grounded gr ids\; the Beam Emission Spectroscopy (BES) diagnostic gives information on the beam intensity and divergence (vertical and horizontal profiles)\; In fra-red (IR) analysis of the diagnostic calorimeter provides a 2D map of t he total beam power and\, consequently\, the accelerated current. \nThe sp atial resolution of the diagnostics allows for identifying and characteriz ing in intensity and divergence the beam segments associated to the two gr id segments. The beam evolution in the segments during the Cs conditioning process (i.e. Cs evaporation in the source in order to move from the volu me production of negative ions to the surface production) has allowed for optimizing the conditioning\, being the beam itself an indirect measuremen t of the status of the negative ion production. During the Cs conditioning \, the presence of two peaks in the main Doppler shifted peak in the BES s pectra have been observed and characterized. When a good and stable Cs con ditioning phase is obtained\, beam uniformity optimization can be investig ated in order to achieve the beam ITER target requirements in terms of uni formity\, i.e. better than $90 \\%$.\n\nhttps://indico.inp.nsk.su/event/11 /contributions/373/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/373/ END:VEVENT BEGIN:VEVENT SUMMARY:Linac4 H- source R&D: Cusp free ICP and magnetron discharge DTSTART;VALUE=DATE-TIME:20180904T050000Z DTEND;VALUE=DATE-TIME:20180904T052500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-385@indico.inp.nsk.su DESCRIPTION:Speakers: Jacques lettry (CERN)\nThe energetic efficiency of t he 2MHz radio-frequency inductively coupled plasma heating (ICP RF) of Lin ac4’s IS03 H- source is twice more efficient once its standard octupole cusp in offset hallbach configuration is removed. This was shown by Partic le in cell Monte-Carlo (PIC-MC) simulation results using the NINJA softwar e [1] and confirmed by plasma characterization via optical emission spectr oscopy [2]\, an easier plasma ignition is also anticipated. In this paper\ , we present preliminary results of an AlN plasma chamber IS03 H- source o perated without magnetic cusp. \nThe high intensity option for Linac4 fea tures an adaptation of BNL’s Magnetron. Simulation of this complex H2-Cs arc discharge plasma\, where electrons are emitted form a cesiated molybd enum cathode\, requires characterization of the plasma impedance dependenc e and knowledge of hydrogen and caesium densities. We present the measured plasma impedance is over the range of discharge current\, hydrogen and ca esium-densities.\n\n1) S. Mattei PhD thesis\, EPFL 7907\, 2017. \n\n2) S Briefi et. al. 2017 New J. Phys. 19 105006.\n\n3) J. Lettry et. al . RSI 87\, 02B139 (2016)\; doi: 10.1063/1.4936120\n\nhttps://indico.inp.ns k.su/event/11/contributions/385/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/385/ END:VEVENT BEGIN:VEVENT SUMMARY:Caesium capture by POCO CZR-2 Graphite on the penning-type H- VESP A source at ISIS DTSTART;VALUE=DATE-TIME:20180904T040000Z DTEND;VALUE=DATE-TIME:20180904T042500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-374@indico.inp.nsk.su DESCRIPTION:Speakers: Tiago Morais Sarmento (ISIS Neutron Source)\nThe sta ndard ISIS Penning-type H– ion source operates with plasma and beam duty cycles of 4% and 1.25%\, respectively\, at 50 Hz repetition rate. It uses pulsed hydrogen injection\, whereas cesium (Cs) is injected continually f rom an external oven. The oven is usually operated at around 160 °C\, whi ch is a compromise between high H– output\, long-term plasma stability a nd low spark rate. Neutral Cs escapes the ion source between plasma pulses and must be trapped. On the ISIS operational source\, a refrigerated ‘c old box’ is used to trap Cs vapor\, however up to 40% beam-loss occurs o n this bulky assembly. A vessel for extraction and source plasma analyses (VESPA) has demonstrated improved beam transport with the cold box removed \, albeit at a higher un-trapped Cs flux. Therefore a new system is being trialled on the VESPA involving POCO CZR-4 graphite used as a Cs getter. F our blocks with a mass totalling 200 g are positioned downstream of the io n source on a mounting frame\, such that they face the source directly wit h a large combined surface area. The blocks were designed in ANSYS for suf ficient thermal isolation to permit in-vacuum bake-out at up to 800 °C. A suite of three quartz crystal microbalances (QCMs) detect Cs flux at vari ous positions in the vacuum vessel. The flux is measured at a range of gra phite heating powers to ascertain the gettering efficiency vs. temperature . In general\, they work best around room temperature so are a true passiv e Cs trap\, effective for any ion source facility which uses Cs.\n\nInitia l results are presented comparing the Cs flux measured using QCMs to the C s0 and Cs+ optical emission intensities as a function of Cs oven temperatu re. This allows a comparison between the amount of Cs present inside the p ulsed plasma and the time-integrated Cs flux escaping between plasma pulse s\, which is subsequently captured. These quantitative Cs measurements and trapping schemes are important for long-term operation of a Penning sourc e with twice the linear dimensions (the ‘2X source’)\, which has been demonstrated to emit a substantially higher Cs flux through its larger bea m emission aperture.\n\nhttps://indico.inp.nsk.su/event/11/contributions/3 74/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/374/ END:VEVENT BEGIN:VEVENT SUMMARY:Beam Current Stability Improvements of Negative Carbon Ions in a M ulti-Cusp Ion Source DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-375@indico.inp.nsk.su DESCRIPTION:Speakers: Stephane Melanson (D-Pace Inc)\nIon implantation req uires a high beam current stability to ensure a uniform implantation dose across the wafers. This requires ion sources with a stable extraction syst em to achieve a high beam current stability. Our goal is to extract 0.5 mA of C2─ with less than 10 glitches per hour\, with a glitch defined as a ny variation greater than +/- 5% of the nominal beam current. The beam ene rgy should be between 10 keV and 30 keV while the normalized 4 RMS emittan ce should be less than 1 mm*mrad. We’ve shown that high negative carbon ion current densities could be obtained with a multi-cusp ion source when acetylene was used as the feed gas (0.25 mA of C2─)\, but there was sign ificant sparking between the electrodes\, which led to frequent beam curre nt glitches (~1000 / hour). In this study\, we investigate the different f actors that contribute to the sparking between the electrodes. We found th at the sparking is highly correlated to the dumping of the co-extracted el ectrons and the beam strike on the electrodes. Extraction simulations were completed to determine how the electron dumping can be improved and how t he beam strikes on the electrodes can be reduced. Furthermore\, we modifie d the magnetic configuration in the plasma chamber to decrease the electro n density close to the extraction aperture\, which reduced the co-extracte d electron current by a factor of almost 5 and reduced sparking frequency to about 20 glitches per hour. However\, there was a corresponding decreas e in the extracted beam current due to the smaller aperture sizes needed t o reduce the sparking\, with only 0.05 mA of C2─.\n\nhttps://indico.inp. nsk.su/event/11/contributions/375/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/375/ END:VEVENT BEGIN:VEVENT SUMMARY:Improvements in D− ion extraction in a multicusp ion source DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-376@indico.inp.nsk.su DESCRIPTION:Speakers: Anand Mathai George (D-Pace\, University of Auckland )\nD-Pace's multi-cusp ion source achieves high DC beam currents for negat ive hydrogen ions in both the TRIUMF licensed filament-powered ion source (~18mA) and the University of Jyväskylä licensed RF ion source (~8mA). However\, the DC beam currents achieved from this source for negative deut erium ions is only 1/3 that of negative hydrogen ions. An earlier study [1 ] revealed that it is possible to extract more negative deuterium ions fro m the source by increasing the intensity of the magnetic dipole filter fie ld in the plasma chamber\, which enables the reduction of plasma electron density and electron temperature. In this paper\, we investigate the effe ct of this increased field on the negative deuterium beam current achieved from the source and also the effect of adding an einzel lens for focusing of the beam.\n\n\n\n[1] A. George\, S. Melanson\, D. Potkins\, M. Dehnel\ , N. Broderick\, H. McDonald and C. Philpott\,"Optimisation of D− ion pr oduction in a multicusp ion source \," in Proc. 9th Int. Particle Accelera tor Conf. (IPAC'18)[To be published]\n\nhttps://indico.inp.nsk.su/event/11 /contributions/376/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/376/ END:VEVENT BEGIN:VEVENT SUMMARY:Improvements to Siemens eclipse PET cyclotron penning ion source DTSTART;VALUE=DATE-TIME:20180905T043000Z DTEND;VALUE=DATE-TIME:20180905T045500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-377@indico.inp.nsk.su DESCRIPTION:Speakers: David Potkins (D-Pace Inc)\, Morgan Dehnel (D-Pace I nc)\nThe Siemens Eclipse (RDS111) cyclotron utilizes an internal Penning I on Gauge (PIG) ion source to provide the negative hydrogen ions for this 1 1 MeV PET cyclotron. Siemens worked with D-Pace Inc. to optimize the ion source current and transmission through the cyclotron to the radioisotope targets. The goal was to increase the target current from 120µA (dual 60 µA) to 150µA (dual 75µA) and to increase the time between ion source re builds from 120 hours to more than 300 hours. Over 80 experiments were co nducted including tests on ion sources with modified cathode\, anode\, and puller lens geometries and materials\, hydrogen gas flow configurations\, and a biased plasma lens design. Cesium was introduced to the source whic h alone increased the beam current on target by over 20%. These short-term tests are being followed up with longer duration field testing.\n\nhttps: //indico.inp.nsk.su/event/11/contributions/377/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/377/ END:VEVENT BEGIN:VEVENT SUMMARY:Langmuir Probe Investigations of Different Magnetic Filter Field C onfigurations at BATMAN Upgrade DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-378@indico.inp.nsk.su DESCRIPTION:Speakers: Loic Schiesko (Max-Planck-Institute für Plasmaphysi k)\nThe Neutral Beam Injection (NBI) system for ITER requires large scale sources for negative hydrogen ions. BATMAN (Bavarian Test Machine for Nega tive Ions) is dedicated to physical investigations due to its flexible acc ess for diagnostics and exchange of source components.\n\nIn 2017\, severa l critical hardware components were upgraded (see W. Kraus contribution fo r details) and BATMAN Upgrade is now commissioned. Among these upgrades\, a major change was made on the magnetic filter field (FF): it is now possi ble to generate the FF by a current flowing through the first grid of the extraction system\, the plasma grid (PG). The magnetic field intensity in front of the PG roughly scale as 2 mT / kA\, and reaches around 6 mT for a maximum current of 3 kA. This value is comparable to the 4.1 mT resulting from the use of permanent magnets installed in the movable frame when loc ated as close as possible to the PG (2x4\, z = 9 configuration\, see [1]). \n\nHowever\, the main difference between current and permanent magnets g enerated magnetic fields is the topology that affects the transport of cha rged particles from the driver where they are generated\, to the PG.\n\nTh e influence induced by the different magnetic field configurations (but al so without FF) on the plasma parameters such as the plasma and floating po tential\, electron temperature\, plasma asymmetry… have been determined by two symmetrically arranged Langmuir probes located in the PG vicinity. Furthermore\, pressure and power scans were performed to better quantify t he FF role on the plasma parameters near the PG.\n\nhttps://indico.inp.nsk .su/event/11/contributions/378/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/378/ END:VEVENT BEGIN:VEVENT SUMMARY:Experimental investigation of a high power long-pulse neutral beam profile diagnostic based on secondary electron emission DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-380@indico.inp.nsk.su DESCRIPTION:Speakers: Kirill Barkalov (NRC "Kurchatov institute")\nDiagnos tic of neutral beam (NB) profiles in powerful long-pulse injectors intende d for plasma heating and current drive in fusion devices is a problem task in consequence of very high NB power density (PD) at a level of tens MW/m 2. NB profiles give an information required for determination of such impo rtant parameters as the beam divergence angle and accuracy of its axis aim ing onto a tokamak entrance window. However\, with so high PD use of probe s introduced directly in the beam is impossible.\n \nIn the case of the IT ER heating injector V-shaped calorimeter is designed for the NB commission ing and determination of its parameters. It consists of two panels\, each is formed by a set of horizontally oriented cooled tubes arranged in two l ayers (“front” and “back”). Use of the thermocouples\, placed on t he tube ends\, allows to measure only horizontally averaged NB vertical pr ofile but horizontal profile remains unknown.\n \nThis report describes me thod of measurement of the beam detailed profiles at the calorimeter using matrix of positively biased collectors\, each of them is placed between t ubes of “back” layer in shadow of “front” layer tube\, i.e. does n ot see the beam. Each collector is to collect secondary emission electrons resulting on surfaces of neighboring tubes under the beam bombardment. Su ch collector matrix is to provide determination of horizontal and vertical profiles in any section of the beam footprint [1].\n\nProposed method was tested on the injector test stand IREK with tubular V-shaped calorimeter. Measurements were carried out with use of positive hydrogen ion source wi th beam energy and current at a level of 40 keV/40 А. The calorimeter was equipped with a set of secondary-emission electron (SEE) collectors and o f tungsten probes\, directly entered into the beam. Initially experiments were carried out with relatively short pulses at a level of 0.4 s for comp arison of normalized profiles measured by both methods and results demonst rated quite good coincidence of the profiles. \n\nFurther measurements wer e done with SEE collectors at pulse duration up to 5 s. An influence of se condary plasma electrons was investigated with changing its density by an increase of the gas pressure in the IREK vacuum vessel.\n\n\n[1] A. Panase nkov\, V. Smirnov. “Method of measurement of neutral beam profile in the long-pulse powerful injectors”. 28-th SOFT 2014 (Spain)\, Book of Abstr acts\, paper P4.022\, p.642.\n\nhttps://indico.inp.nsk.su/event/11/contrib utions/380/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/380/ END:VEVENT BEGIN:VEVENT SUMMARY:Operation experience of the BINP Accelerator Mass Spectrometer DTSTART;VALUE=DATE-TIME:20180905T063000Z DTEND;VALUE=DATE-TIME:20180905T065500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-381@indico.inp.nsk.su DESCRIPTION:Speakers: Sergey Rastigeev (Budker Institute of Nuclear Physic s)\nThe accelerator mass spectrometer (AMS)\, created at BINP\, is used fo r an ultra-sensitive radiocarbon concentration measurements for archaeolog y\, geology\, biomedical science and other fields. \n\nThe BINP AMS is bas ed on the 1MV folded tandem accelerator with C+++ ion selection.\nThe most distinguishing feature of BINP AMS is the use of electrostatic separator of ion beam\, located inside the high voltage terminal. The next important distinguishing feature is magnesium vapors stripper instead of the gas st ripper. Moreover\, the moment of time for ion detection can be registered by TOF detector. \n\nThe BINP AMS capabilities for pure radiocarbon beam s election and about 10 years operating experience will be described.\n\nhtt ps://indico.inp.nsk.su/event/11/contributions/381/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/381/ END:VEVENT BEGIN:VEVENT SUMMARY:Numerical Simulation for the Development of DC Arc-discharge Hydro gen Negative Ion Source for Medical Use DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-382@indico.inp.nsk.su DESCRIPTION:Speakers: Shota YAMADA (Keio University)\n$\\\,\\\,\\\,\\\,\\\ ,\\\,\\\,\\\,$Multi cusp DC arc-discharge hydrogen negative ion ($\\mathrm {H}^-$) source has been developed for proton cyclotron\, which is used fo r Boron Neutron Capture Therapy (BNCT) [1\, 2]. In order to shorten the tr eatment time for BNCT\, it is required to get high extracted beam current from the source.\n\n$\\\,\\\,\\\,\\\,\\\,\\\,\\\,\\\,$The final goal of th is study is to understand the dependence of the $\\mathrm {H}^-$ productio n on the operation parameters and optimize the $\\mathrm {H}^-$ production in the source.\n\n$\\\,\\\,\\\,\\\,\\\,\\\,\\\,\\\,$In this study\, we fo cus on the $\\mathrm {H}^-$ surface production which is a dominant process of $\\mathrm {H}^-$ production. We’ve developed a 3D particle simulatio n model which simulates the $\\mathrm {H}^-$ surface production process in the source. The simulation process consists of (i) electron transport ana lysis and (ii) neutral transport analysis. In the former\, the electron en ergy distribution function: EEDF in the source has been calculated by KEIO -MARC code [3\, 4\, 5]. In the latter\, following calculation has been con ducted\, 1) the transport processes of neutrals ($\\mathrm {H}_2$\, H) are simulated considering the important collision processes by using Monte Ca rlo Method\, 2) the H atom flux onto the Plasma Grid (PG) is calculated\, and 3) the $\\mathrm {H}^-$ production on the PG surface is calculated by using Rasser’s formula [6].\n \n$\\\,\\\,\\\,\\\,\\\,\\\,\\\,\\\,$Based on the above model\, we are now performing a series of numerical simulatio ns. In this paper\, we report the dependence of $\\mathrm {H}^-$ surface p roduction on the following parameters\, (a) the position of the filament a nd (b) the configuration of filter magnetic field. These simulation result s will be useful for the optimization of the $\\mathrm {H}^-$ production i n the source. \n\n$\\\,\\\,\\\,$\n\nReferences\n\n[1] Etoh H\, Aoki Y\, M itsubori H et al. 2014 Rev. Sci. Instrum. $\\bf{87}$ 02B107.\n\n[2] Etoh H \, Onai M\, Aoki Y\, et al. 2016 Rev. Sci. Instrum. $\\bf{87}$ 02B135.\n\n [3] Fujino I\, Hatayama A\, Takado N and Inoue T\, 2008 Rev. Sci. Instrum. $\\bf{79}$ 02A510\n\n[4] Terasaki R\, Fujino I\, Hatayama A\, Mizuno T an d Inoue T\, 2010\, Rev. Sci. Instrum. $\\bf{81}$ 02A703.\n\n[5] Shibata T\ , Kashiwagi M\, Inoue T\, Hatayama A\, and JAEA NBI Group 2013 J. Appl. Ph ys\, $\\bf{114}$ $\\\,\\\,\\\,\\\,\\\,\\\,\\\,\\\,$143301.\n\n[6] B. Rass er et al\, Surf. Sci. $\\bf{118}$\, 697(1982).\n\nhttps://indico.inp.nsk.s u/event/11/contributions/382/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/382/ END:VEVENT BEGIN:VEVENT SUMMARY:Methods of Beam Emittance Measurements of High Power Negative Ion Beams for NBIs DTSTART;VALUE=DATE-TIME:20180906T043000Z DTEND;VALUE=DATE-TIME:20180906T045500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-383@indico.inp.nsk.su DESCRIPTION:Speakers: Glynnis Mae Saquilayan (National Institutes for Quan tum and Radiological Science and Technology)\nThe development of a high po wer negative ion beam accelerator is one of the key aspects in the neutral beam injection system (NBI) for fusion reactors. For example\, the ITER N BI requires 1 MeV deuterium negative ion (D-) beams with a current density of 200 A/m2 and a divergence angle of - ion beamlets being projected on t his CFC target are measured using an infrared camera to observe the emitta nce spread. The advantage of this thermal measurement is the simple config uration and lack of additional electrical components that can contribute t o the noise in the signal. Another method to be tested is the slit-collect or type where an array of slits produces the beamlets while collectors are arranged to scan the cross-section and measure the transverse emittance w ith high spatial resolution. The reliability of this electrical type of de tection will offer a good comparison to the pepperpot method as to identif y the key features of each measurement technique. Examining the beam emitt ance will also reveal the characteristics of the diverging beam components crucial to beam transport. From performance of the different emittance me asurement methods\, a beam diagnostics system will be proposed suitable to monitor the ITER-class negative ion beam.\n\nhttps://indico.inp.nsk.su/ev ent/11/contributions/383/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/383/ END:VEVENT BEGIN:VEVENT SUMMARY:Inductive RF drivers for neutral beam injectors at BINP DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-384@indico.inp.nsk.su DESCRIPTION:Speakers: Igor Shikhovtsev (Budker Institute of Nuclear Physic s)\nIn the last decade\, a series of high power neutral beam injectors for plasma heating and diagnostics in magnetic fusion experiments has been de veloped at the Budker Institute of Nuclear Physics. In the injectors\, the plasma emitter is produced by inductively coupled radio frequency dischar ge. With this emitter of difference size\, positive ion hydrogen and deute rium beams with energy up to 60 keV and power up to 1.6 MW can be provided . In the last few years\, the negative ion sources with the RF drivers hav e been developed for the injector with higher energies. This paper present s an overview of the design\, parameters and performance of the developed plasma drivers.\n\nhttps://indico.inp.nsk.su/event/11/contributions/384/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/384/ END:VEVENT BEGIN:VEVENT SUMMARY:Fluid Modeling of Negative Hydrogen Ion Sources DTSTART;VALUE=DATE-TIME:20180906T020000Z DTEND;VALUE=DATE-TIME:20180906T022500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-386@indico.inp.nsk.su DESCRIPTION:Speakers: Seth Veitzer (Tech-X Corporation)\nNegative hydrogen ion sources are widely used to produce neutron beams\, relevant to both a ccelerators and fusion devices. There are a number of different kinds of n egative hydrogen sources in use today\, including inductively coupled plas ma sources (ICPs). For instance\, coils external to the ion source chambe r can be designed to deposit power into hydrogen plasmas to create highly excited ionic states\, which then can produce negative hydrogen ions. Mode ling ICP ion sources using traditional Particle-In-Cell (PIC) codes is dif ficult because of inherent separation of time scales between electron and ion motions severely limits the number of rf periods that can be modeled w ith currently available computational resources. In some cases\, fluid-ba sed models can be used to overcome these difficulties. For these models\, simplifying assumptions are made about the electrons and their energy dis tributions that enable longer time steps. The loss of information about el ectron kinematics may not be so important in determining the plasma chemis try and valid predictions of ion source performance can in some cases be o btained using fluid-based models.\n\nWe present our progress developing a drift-diffusion model implemented using the USim plasma-fluid framework. T his model is able to capture both the deposition of energy into the source plasma and diffusion of energy and density from rf and DC power sources\, and also the production of different ion species and vibrational states t hrough inclusion of plasma chemistry models. We first determine the larges t reaction rates in the production of negative hydrogen using a global mod el\, which depends on the specific parameters of the ion source being mode led\, such as neutral gas density and geometric factors for surface proces ses. These rates determine the ion species that are needed in simulations in order to model negative hydrogen production. rf power deposition into t he plasma is done separately from the drift-diffusion solve\, but for dens e plasmas modeled here\, the numerical time-step restrictions for rf power deposition are typically larger than those for modeling the plasma chemis try\, and so do not reduce simulation performance.\n\nFluid model equation s corresponding to electron number and energy density are solved numerical ly on either structured or unstructured meshes. Source terms for the elect ron number densities are determined by the plasma chemistry\, while source s for the energy density equations are a result of both inelastic collisio ns and energy deposition from external electromagnetic fields. We apply o ur models to the simulation of the SNS external antenna negative hydrogen ion source\, and demonstrate the feasibility of using fluid-based models f or simulation of these types of ICPs for negative hydrogen ion production. We note that we are developing model capabilities that are general enough to be applied to a large variety of different geometries\, electric field configurations\, and plasma parameters.\n\n\nThis work was performed unde r the auspices of the Department of Energy\, Office of Basic Energy Scienc es Award #DE-SC0009585.\n\nhttps://indico.inp.nsk.su/event/11/contribution s/386/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/386/ END:VEVENT BEGIN:VEVENT SUMMARY:Studies on the voltage hold off of the SPIDER driver coil at high RadioFrequency power DTSTART;VALUE=DATE-TIME:20180903T084000Z DTEND;VALUE=DATE-TIME:20180903T105000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-387@indico.inp.nsk.su DESCRIPTION:Speakers: Mauro Recchia (Consorzio RFX)\nSPIDER is the prototy pe of the ion source of the ITER Neutral Beam Injector presently in operat ion at the Neutral Beam Test Facility in Padova\, Italy\, designed to del iver an ion current density of 355A/m2 in H- (285 A/m2 in D-) and to acce lerate the beam of extracted particles up to 100 keV energy. SPIDER is equ ipped with a plasma source composed of 8 Radio Frequency (RF) drivers each transferring 100 kW power at the frequency of 1 MHz to the plasma via mag netic inductive coupling. The driver coil is separated from the plasma by a dielectric driver case\; it works at an estimated pressure of about 0.06 Pa (in Hydrogen operation and with source pressure of 0.3 Pa) and it reac hes a voltage of 12 kV rms at full power. A set of 4 dielectric supports c alled combs\, placed around the driver case\, assures the separation in be tween coil turns. Both the combs and the driver case contribute to the mec hanical support of the coil. \nThe present design of the SPIDER plasma sou rce is the one implemented during the procurement of the source and follow s the concepts previously developed and proved at IPP Garching. However\, further studies have proceeded in parallel to the SPIDER construction\, bo th at theoretical and experimental level\, due to its more stringent requi rements. One important topic analyzed has been the power handling capabili ty of the driver\; in fact\, the performance in terms of ion current of th e beam source increases with the radiofrequency power level\, which howeve r raises issues related to the voltage hold off of the driver components. The risk of possible breakdowns at the driver coils with the power increas e\, already experienced on other devices\, has been identified for SPIDER too\; the paper reports the present status of the electrical analyses of t he SPIDER driver coil region.\n\nhttps://indico.inp.nsk.su/event/11/contri butions/387/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/387/ END:VEVENT BEGIN:VEVENT SUMMARY:Development of surface-plasma negative ions sources at BINP DTSTART;VALUE=DATE-TIME:20180906T070000Z DTEND;VALUE=DATE-TIME:20180906T072500Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-388@indico.inp.nsk.su DESCRIPTION:Speakers: Yuri Belchenko (Budker Institute of Nuclear Physics) \nA review of surface-plasma negative ions sources developed in the Budker Institute of Nuclear Physics for use in accelerators and neutral injector s for fusion experimental devices in last decade is presented. Physical pr ocesses\, main properties and features of surface-plasma sources with vari ous high-current discharge drivers are analyzed. Key issues and solutions in achieving the sources high power efficiencies\, reliable long-term oper ation and easy maintenance will be discussed.\n\nhttps://indico.inp.nsk.su /event/11/contributions/388/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/388/ END:VEVENT BEGIN:VEVENT SUMMARY:MITICA Intermediate Electrostatic Shield: concept design\, develop ment and first experimental tests identification DTSTART;VALUE=DATE-TIME:20180904T083000Z DTEND;VALUE=DATE-TIME:20180904T110000Z DTSTAMP;VALUE=DATE-TIME:20260718T062920Z UID:indico-contribution-11-389@indico.inp.nsk.su DESCRIPTION:Speakers: Tommaso Patton (Consorzio RFX)\nThe high-Q operation of the ITER tokamak will require two Neutral Beam Injectors (NBIs) for pl asma heating and current drive. Each beam will be generated by a 40A curr ent of Deuterium negative ions\, accelerated up to the specific energy of 1MeV and then neutralized. The power delivered to the plasma by each NBI shall reach 16 MW with a duration up to 1h. The beam source will be const ituted by an RF-driven negative ion source at –1 MV potential\, by a Mul ti-Aperture\, Multi-Grid (MAMuG) electrostatic accelerator (consisting of 5 stages at intermediate potentials)\, and a gas-box neutralizer at ground potential. All components will be installed in a vacuum vessel (also at g round potential)\, together with a high-capacity cryo-pumping system which controls of the background gas pressure. \nIn order to validate the ITER NBI design and address all the outstanding issues related to these demand ing requirements\, a full scale prototype called MITICA (Megavolt ITER Inj ector & Concept Advancement)\, is under construction in Padova at Consorzi o RFX.\nVoltage insulation in vacuum and/or very low-pressure gas on a sin gle gap is indeed one of the expected issues which MITICA will have to dea l with. \nIn this paper\, a numerical tool\, called Voltage Holding Predi ction Model (VHPM) and based on the clumps theory in vacuum\, is applied t o the MITICA beam source for evaluating and optimizing the high voltage in sulation of the experiment. The tool parameters have been recently "calibr ated" based on the (few) experimental results presently available in the case of large gaps. \nSince the initial results suggest that the breakdown probability will be rather high when the beam source will operate at nomi nal voltage (-1MV)\, preemptive solutions for increasing the voltage hold ing capability in the gaps between the beam source\, the accelerator grids and the vacuum vessel have been considered ad compared . \nA very effec tive solution for increasing the voltage holding capability of the system consists in the use of an intermediate electrostatic shield between the so urce and the vessel. Using the above-mentioned numerical tool\, a conceptu al design of such intermediate electrostatic shield has been developed and optimized\, taking into account also mechanical constraints\, and the ef fects of the presence of the shield on the background gas pressure distrib ution.\nFinally also an experimental program for anticipating the full-sca le voltage holding tests is studied and proposed\, using the real MITICA v acuum vessel (on-site) together with a beam source mock-up (with a simple geometry) without and with an intermediate electrostatic shield\, in order to get a first voltage holding characterization of the vacuum vessel\, to evaluate the effect of the shield\, and to benchmark the VHPM for large g aps.\n\nhttps://indico.inp.nsk.su/event/11/contributions/389/ LOCATION: URL:https://indico.inp.nsk.su/event/11/contributions/389/ END:VEVENT END:VCALENDAR