Conveners
P2
- Mahendrajit Singh (ITER-India, Inst. for Plasma Research)
- Zhimin Liu (a) Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; b) University of Science and Technology of China, Hefei 230026, China)
The Gas Insulated Transmission Line (GITL), which is an important link between radio frequency negative ion source and the power supply system, carries all the Ion Source and the Extraction Power Supplies (ISEPS) conductors at -400kV with respect to ground, from High Voltage Deck (HVD) to the beam source and the intermediate potentials of acceleration grids. The corner section, which is...
We have discussed in the previous meetings on the possible improvements for the negative ion to electron current ratio by depositing fresh coating of tantalum (Ta) on the plasma grid surface of a negative hydrogen (H-) ion source [1]. A fresh Ta evaporation by burning a thin Ta filament increased H- ion current by 12 % [2]. However, the enhanced H- production lasted only about one hour after...
Toward the coming JT-60SA tokamak operation, negative ion sources producing 500 keV and 22 A (130 A/m$^2$) H-/D- beams for 100 s are being developed for the JT-60SA neutral beam injector. So far, the extraction of 15 A H$^-$ beams for 100 s has been achieved, however, there are two remaining issues related to the unclear Cs behavior in the large size negative ion source (~1.2 m x 0.68 m x 0.55...
Negative ions as well as singly and multiply charged positive ions are generated in a laser produced plasma. During laser vaporization of the target, various atomic processes related to negative ion production take place involving radiative capture, dielectronic recombination, and ternary collisions, where the last is found to be most probable in the case of a laser plasma due to its high...
Recently the C12A7 electride attracts much attention as one of the possible plasma electrode material of Cs-free negative hydrogen isotope (H⁻/D⁻/T⁻) ion sources[1-2].
In this work, H-/D⁻ spectra from a C12A7 electride target immersed in an ICP plasma was measured in the apparatus, Phisis[3] . The target was biased negatively against the electrically grounded chamber. The temperature of the...
Introduction of cesium (Cs) into an ion sources enhances the production of negative hydrogen (H$^-$) ions while suppresses the co-extracted electron current by reducing the work function of the plasma grid surface [1-2]. However, cesium injection into an ion sources should require periodical maintenance and can add serious complexity in operation in a strong neutron /gamma radiation...
Radiation temperature measurement is acquired widely to be based on the famous Planck's law of blackbody radiation, which indicate that any object with a temperature higher than absolute zero is constantly radiating infrared rays outward. According to the law, the radiation emission at a given temperature is constant in object and varies among materials which ruled by its emission rate.
Just...
According to the latest physics design of the China Fusion Engineering Test Reactor (CFETR), radio-frequency(RF) driven negative ion sources are selected as the preferred ion source for CFETR neutral beam injector (NBI).To solve the key problems of the CFETR, the engineering design, development, and construction of the Comprehensive Research Facility for Fusion Technology (CRAFT) has begun....
Due to reliability issues in using cesium (Cs) for efficient hydrogen negative ion production in ion sources for neutral beam injection (NBI) systems in fusion research, many researchers have explored Cs-free alternatives to Cs for a future DEMOnstration power station (DEMO) NBI system. The Korea Atomic Energy Research Institute (KAERI) recently launched a new project in collaboration with...
The Los Alamos Neutron Science (LANSCE) linear accelerator provides an 800 MeV beam of
negative hydrogen ions (H-) to several facilities, e.g., pRad, a proton radiography studies facility
and the PSR, a proton storage ring which accumulates ions to be delivered to a target at the
Lujan Center for the production of neutrons by spallation.
The negative ion branch of LANSCE starts at an ion...
Many types of negative hydrogen (H$^-$) ion sources are operated by injecting cesium (Cs) into the discharge. The injected Cs reduces the surface work function of the extraction electrode to enhance negative ion current and reduce coextracted electron current. The high H$^-$ ion density in the vicinity of the beam extraction hole is believed to be realized by negative ionization of incoming...
