DOUBLY-DIFFERENTIAL IONIZATION CROSS-SECTIONS OF POSITRON-IMPACT ON ARGON

被引:1
作者
SCHMITT, A
CERNY, U
FALKE, T
MOLLER, H
RAITH, W
WEBER, M
机构
[1] Fakultät fiir Physik, Universität Bielefeld, Bielefeld
来源
HYPERFINE INTERACTIONS | 1994年 / 89卷 / 1-4期
关键词
D O I
10.1007/BF02064503
中图分类号
O64 [物理化学(理论化学)、化学物理学]; O56 [分子物理学、原子物理学];
学科分类号
070203 ; 070304 ; 081704 ; 1406 ;
摘要
We report the first measurement of doubly-differential ionization cross sections for positron impact on argon atoms. Energy- and angle-resolved measurements of ejected electrons in time correlation with the produced and detected ions have been performed. Corresponding measurements with incident electrons were made far comparison. With positrons and electrons as primary particles of 100 eV energy and ejected electrons of 15 eV, our measurements were extended over electron-emission angles from 0 degrees to 90 degrees. Lacking theoretical predictions for the doubly-differential ionization of argon, we compare our measured data with the theoretical doubly-differential ionization cross sections, calculated for positron and electron impact on hydrogen by Klar and Berakdar (Freiburg) [1]. The angular dependence of positron and electron cross sections for argon agrees well with the theory for hydrogen. In particular, we found that for small angles of electron ejection the cross section for positron impact ionization exceeds that for electron impact by an order of magnitude in accordance with the predictions of Klar and Berakdar.
引用
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页码:133 / 140
页数:8
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