Sputtering of negative hydrogen ions by cesium bombardment

Journal Article · Tue Jul 01 04:00:00 EDT 1986 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.337800· OSTI ID:5612039

Lopes, J L; Greer, J A; Seidl, M

The production of negative hydrogen ions sputtered from a low work function converter surface has been investigated. Hydrogen and cesium admitted into the vacuum chamber are chemisorbed on a polycrystalline molybdenum target. H/sup -/, Mo/sup -/, and e/sup -/ are sputtered from this cathode by Cs/sup +/ ions in the energy range 150--1000 eV. Angular and parallel energy distributions of H/sup -/, Mo/sup -/, and e/sup -/ are measured as a function of hydrogen gas pressure, cesium coverage, and incident ion energy. For optimum coverage, the H/sup -/ ion temperature varies from 0.65% and 0.35% of the incident Cs/sup +/ bombarding energy for Cs/sup +/ ion energies of 250 and 1000 eV, respectively. The secondary electrons have a temperature of 0.04% of the bombarding energy almost independent of Cs/sup +/ energy. The spreads increase with decreasing target coverage and are independent of surface roughness. The optimum H/sup -/, Mo/sup -/, and e/sup -/ yields are also measured as a function of hydrogen pressure and incident Cs/sup +/ bombarding energy. The optimum H/sup -/ ion yield is 0.41 at a Cs/sup +/ ion energy of 750 eV. By extrapolating the H/sup -/ ion yield at low Cs/sup +/ bombarding energy, a Cs/sup +/ ion threshold energy of 120 eV may be estimated. This indicates a binding energy of hydrogen smaller than 3.6 eV.

• Research Organization: Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, New Jersey 07030
• DOE Contract Number: AC02-84ER53167
• OSTI ID: 5612039
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 60:1; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

640301* -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANIONS
BEAM PRODUCTION
BEAMS
BINDING ENERGY
CESIUM IONS
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISORPTION
COLLISIONS
ELECTRON BEAMS
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
EMISSION
ENERGY
ENERGY RANGE
ENERGY SPECTRA
EV RANGE
EV RANGE 100-1000
FERMIONS
HYDROGEN 1 MINUS BEAMS
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
ION BEAMS
ION COLLISIONS
ION SOURCES
IONS
KEV RANGE
KEV RANGE 01-10
LEPTON BEAMS
LEPTONS
METALS
MOLYBDENUM
MOLYBDENUM IONS
PARTICLE BEAMS
ROUGHNESS
SECONDARY EMISSION
SEPARATION PROCESSES
SORPTION
SPECTRA
SPUTTERING
SURFACE PROPERTIES
TRANSITION ELEMENTS