Energy dependence of the positronium formation cross-section in argon

摘要: The positronium (Ps) formation cross-section, QPs, for positron–argon interactions has been measured incident positron energies from threshold to 60 eV, in an attempt resolve the apparent discrepancy between earlier experimental results. QPs was found vary smoothly with energy 15 and 30 qualitative agreement results using methods involving measurement of neutralization (as current experiment) disagreement double-peak dependence reported by Laricchia et al (2002 J. Phys. B: At. Mol. Opt. 35 2525–40), who used a positron-ion coincidence detection method. Possible reasons this discrepancy, including Ps fragmentation excited-state formation, are discussed.