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Title: Determination of discharge parameters via OES at the Linac4 H{sup −} ion source

Optical emission spectroscopy (OES) measurements of the atomic Balmer series and the molecular Fulcher transition have been carried out at the Linac4 ion source in order to determine plasma parameters. As the spectroscopic system was only relatively calibrated, the data evaluation only yielded rough estimates of the plasma parameters (T{sub e} ≈ 1.2 eV, n{sub e} ≈ 1 × 10{sup 19} m{sup −3}, and n{sub H}/n{sub H{sub 2}} ≈ 0.5 at standard operational parameters). The analysis of the Fulcher transition revealed a non-thermal “hockey-stick” rotational population of the hydrogen molecules. At varying RF power, the measurements at the on-axis line of sight (LOS) showed a peak in the rotational temperatures between 25 and 40 kW of RF power, whereas a steady decrease with power was observed at a tilted LOS, indicating the presence of strong plasma parameter gradients.
Authors:
 [1] ; ; ;  [2] ;  [1] ;  [3]
  1. AG Experimentelle Plasmaphysik, Institut für Physik, Universität Augsburg, 86135 Augsburg (Germany)
  2. Linac4 Ion Source Team, CERN-ABP, 1211 Geneva 23 (Switzerland)
  3. (Germany)
Publication Date:
OSTI Identifier:
22482926
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; EMISSION SPECTROSCOPY; HYDROGEN; ION SOURCES; LINEAR ACCELERATORS; PEAKS; PLASMA