Eur. Phys. J. D (2017) 71: 170
https://doi.org/10.1140/epjd/e2017-70500-9

Regular Article

Single and double over-barrier ionization of He, He⁺ and Ne system by positron impact

School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, P.R. China

^a e-mail: shaojx@lzu.edu.cn

Received: 7 August 2016
Received in final form: 22 March 2017
Published online: 22 June 2017

Abstract

The classical over-barrier ionization model (COBI) method and trajectory calculations were utilized to simulate the ionization of He⁺ impacted by a positron. The calculated ionization cross sections of He⁺ agree with other theoretical data. Additionally, we found that the double ionization of He has a definite association with the positron-He⁺ impact. This result can explain why doubly ionized He seemed to be positron-scattered by the rest of the He⁺ in our previous study. The COBI model was also extended to study the double ionization caused by positron-Ne impacts. Our theoretical results agree with the experimental data.