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Title: Self-focusing of a high current density ion beam extracted with concave electrodes in a low energy region around 150 eV

Spontaneous self-focusing of ion beam with high current density (J{sub c} ∼ 2 mA/cm{sup 2}, I{sub b} ∼ 65 mA) in low energy region (∼150 eV) is observed in a hydrogen ion beam extracted from an ordinary bucket type ion source with three electrodes having concave shape (acceleration, deceleration, and grounded electrodes). The focusing appears abruptly in the beam energy region over ∼135–150 eV, and the J{sub c} jumps up from 0.7 to 2 mA/cm{sup 2}. Simultaneously a strong electron flow also appears in the beam region. The electron flow has almost the same current density. Probably these electrons compensate the ion space charge and suppress the beam divergence.
Authors:
 [1] ;  [2] ; ;  [1] ;  [1] ;  [2]
  1. Innovative Plasma Technologies Group, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki (Japan)
  2. (Japan)
Publication Date:
OSTI Identifier:
22253249
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 2; Conference: ICIS 2011: 14. international conference on ion sources, Giardini-Naxos, Sicily (Italy), 12-16 Sep 2011; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; CRITICAL CURRENT; CURRENT DENSITY; ELECTRODES; ELECTRONS; EV RANGE 100-1000; FOCUSING; HYDROGEN IONS; ION BEAMS; ION SOURCES; SPACE CHARGE