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Title: Negative hydrogen ion yields at plasma grid surface in a negative hydrogen ion source

Negative hydrogen (H{sup −}) ion yield from the plasma grid due to incident hydrogen ions and neutrals has been evaluated with the surface collision cascade model, ACAT (Atomic Collision in Amorphous Target) coupled to a negative surface ionization models. Dependence of negative ion fractions upon the velocity component normal to the surface largely affect the calculation results of the final energy and angular distributions of the H{sup −} ions. The influence is particularly large for H{sup −} ions desorbed from the surface due to less than several eV hydrogen particle implact. The present calculation predicts that H{sup −} ion yield can be maximized by setting the incident angle of hydrogen ions and neutrals to be 65 degree. The Cs thickness on the plasma grid should also affect the yields and mean energies of surface produced H{sup −} ions by back scattering and ion induced desorption processes.
Authors:
 [1] ;  [2] ;  [3]
  1. Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 Japan (Japan)
  2. School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto 610-0321 Japan (Japan)
  3. Office of R and D Promotion, Doshisha University, Kamigyoku, Kyoto 602-8580 Japan (Japan)
Publication Date:
OSTI Identifier:
22391401
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1655; Journal Issue: 1; Conference: NIBS 2014: 4. International Symposium on Negative Ions, Beams and Sources, Garching (Germany), 6-10 Oct 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANGULAR DISTRIBUTION; ATOM COLLISIONS; BACKSCATTERING; CESIUM; DESORPTION; EV RANGE; HYDROGEN IONS 1 MINUS; PLASMA; SURFACE IONIZATION; SURFACES; YIELDS