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Title: Anion formation in sputter ion sources by neutral resonant ionization

Focused Cs{sup +} beams in sputter ion sources create mm-diameter pits supporting small plasmas that control anionization efficiencies. Sputtering produces overwhelmingly neutral products that the plasma can ionize as in a charge-change vapor. Electron capture between neutral atoms rises as the inverse square of the difference between the ionization potential of the Cs state and the electron affinity of the sputtered atom, allowing resonant ionization at very low energies. A plasma collision-radiation model followed electronic excitation up to Cs(7d). High modeled Cs(7d) in a 0.5 mm recess explains the 80 μA/mm{sup 2} C{sup −} current density compared to the 20 μA/mm{sup 2} from a 1 mm recess.
Authors:
 [1]
  1. University of California, 8300 Feliz Creek Dr., Ukiah, California 95482 (United States)
Publication Date:
OSTI Identifier:
22482857
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; AFFINITY; ANIONS; ATOMS; BEAMS; CESIUM IONS; COLLISIONS; CONTROL; CURRENT DENSITY; ELECTRON CAPTURE; EXCITATION; ION SOURCES; IONIZATION; PLASMA; SPECTROSCOPY; SPUTTERING; VAPORS