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Title: First experiments with Cs doped Mo as surface converter for negative hydrogen ion sources

A study was conducted on the properties of molybdenum implanted with caesium as an approach to reduce the Cs consumption of negative hydrogen ion sources based on evaporated Cs. The depth profiles of the implanted Cs were simulated by SDTrimSP and experimentally determined by X-ray photoelectron spectroscopy depth profiling. In particular, one year after implantation, the depth profiles showed no signs of Cs diffusion into the molybdenum, suggesting long term stability of the implanted Cs atoms. The H{sup −} surface generation mechanisms on the implanted samples in hydrogen plasma were investigated, and the stability of the H{sup −} yield during four hours low power hydrogen plasma discharges was demonstrated. An estimation of the work function reduction (−0.8 eV) by the Cs implantation was performed, and a comparison of the relative negative ion yields between the implanted samples and highly oriented pyrolitic graphite showed that the Cs doped Mo negative ion yield was larger.
Authors:
; ; ; ; ; ;  [1] ; ;  [2] ;  [2] ;  [3]
  1. Max-Planck-Institut für Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany)
  2. Aix Marseille University, CNRS, PIIM, UMR 7345, F-13013 Marseille (France)
  3. (France)
Publication Date:
OSTI Identifier:
22494758
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 7; Other Information: (c) 2015 EURATOM; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANIONS; CESIUM; COMPUTERIZED SIMULATION; DIFFUSION; DOPED MATERIALS; EXPERIMENT RESULTS; GRAPHITE; HYDROGEN; HYDROGEN IONS; MOLYBDENUM; PLASMA; WORK FUNCTIONS; X-RAY PHOTOELECTRON SPECTROSCOPY; YIELDS