BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:First Beam Extraction Experiments at BATMAN Upgrade DTSTART;VALUE=DATE-TIME:20180904T064000Z DTEND;VALUE=DATE-TIME:20180904T070500Z DTSTAMP;VALUE=DATE-TIME:20260909T093346Z UID:indico-contribution-36-298@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:The NIO1 negative ion source: investigation and operation experien ce DTSTART;VALUE=DATE-TIME:20180904T074000Z DTEND;VALUE=DATE-TIME:20180904T081000Z DTSTAMP;VALUE=DATE-TIME:20260909T093346Z UID:indico-contribution-36-302@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:Spectroscopic Investigations of the Ion Source at BATMAN Upgrade DTSTART;VALUE=DATE-TIME:20180904T071000Z DTEND;VALUE=DATE-TIME:20180904T073500Z DTSTAMP;VALUE=DATE-TIME:20260909T093346Z UID:indico-contribution-36-368@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 END:VCALENDAR