Comment on “Isotopic mass effects for low-energy channeling in a silicon crystal”

Abstract

In April, 2010, after reading “An improved critical angle equation for ion channeling” (Zheng theory) proposed by Zheng et al. (1) in Nuclear Instruments and Methods in Physics Research Section B (NIM-B), we felt very strange, because the theory contradicts the well-known Lindhard theory (2) and many of the experimental results published during the last few decades (3). Therefore, we submitted our first comments (4) to NIM-B for publication on 15 April 2010. In September 2010, we had found a new paper published by Zheng et al. (5) in Radiation Effects and Defects in Solids. In the latter paper (5), Zheng et al. studied the isotopic mass effects for low-energy channeling in a silicon crystal by using Monte Carlo (MC) simulations. Immediately, we remembered that a similar work had been published by Zheng et al. two years before for low-energy ion channeling in single-wall carbon nanotubes (SWCNT) (6). The aim of the two papers (5, 6) is finding simulation evidence to support the Zheng theory (1) by studying isotopic ion channeling.

Keywords:

• critical angle
• mass effect
• ion channeling
• positron channeling

Acknowledgements

One of the authors, Lai Zhang, would like to thank Dr Azer Yalin, Professor in the Department of Mechanical Engineering at Colorado State University in USA, for his invitation and financial support.