Pickoff and spin conversion of orthopositronium in oxygen - art. no. 042702

Citation
N. Shinohara et al., Pickoff and spin conversion of orthopositronium in oxygen - art. no. 042702, PHYS REV A, 6404(4), 2001, pp. 2702
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
PHYSICAL REVIEW A
ISSN journal
1050-2947 → ACNP
Volume
6404
Issue
4
Year of publication
2001
Database
ISI
SICI code
1050-2947(200110)6404:4<2702:PASCOO>2.0.ZU;2-5
Abstract
The quenching processes of the thermalized orthopositronium (o-Ps) on an ox ygen molecule have been studied by the positron annihilation age-momentum c orrelation technique. The Doppler-broadening spectrum of the 511-kev gamma rays from the 2 gamma annihilation of o-Ps in O-2 has been measured as a fu nction of the o-Ps age. The rate of the quenching, consisting of the pickof f and the spin conversion, is estimated from the positron lifetime spectrum . The ratio of the pickoff quenching rate to the spin-conversion rate is de duced from the Doppler broadening of the 511-kev gamma rays from the annihi lation of the o-Ps. The pickoff parameter (1)Z(eff), the effective number o f the electrons per molecule that contribute to the pickoff quenching, for O-2 is determined to be 0.6+/-0.4. The cross section for the elastic spin-c onversion quenching is determined to be (1.16+/-0.01) x 10(-19) cm(2).