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Measurements of total and positronium formation cross sections for positrons and electrons scattered by hydrogen atoms and molecules

Journal Article · · Physical Review A
; ; ; ;  [1]
  1. Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48202 (United States)
We have measured total (Q{sub T}) and positronium formation (Q{sub Ps}) cross sections for 1{endash}302-eV positrons (e{sup +}{close_quote}s) and Q{sub T}{close_quote}s for electrons (e{sup {minus}}{close_quote}s) scattered by hydrogen atoms and molecules. A beam transmission technique is used to measure Q{sub T}{close_quote}s where the projectile beam passes through a low-temperature scattering cell containing a mixture of hydrogen atoms and molecules generated in an adjacent radio-frequency discharge region. Q{sub Ps}{close_quote}s are measured using the same scattering cell by detecting coincidences of 511-keV annihilation {gamma} rays produced by the decay of para-Ps and by the interaction of ortho-Ps with the walls of the scattering cell in which the Ps is formed. The present e{sup +}-H Q{sub T}{close_quote}s and Q{sub Ps}{close_quote}s agree very well with theoretical calculations. Comparisons of the present e{sup +} and e{sup {minus}}-H Q{sub T}{close_quote}s show a merging to within 20{percent} for energies above 12 eV. {copyright} {ital 1997} {ital The American Physical Society}
OSTI ID:
435200
Journal Information:
Physical Review A, Journal Name: Physical Review A Journal Issue: 1 Vol. 55; ISSN 1050-2947; ISSN PLRAAN
Country of Publication:
United States
Language:
English