基于弹性背散射率的低能电子IMFP计算

Monte Carlo simulation of electron IMFP from elastic backscattering probability

采用蒙特卡罗程序对Fe、Cu、Ag和Au表面的电子弹性背散射过程进行了研究。模拟程序中电子的弹性散射截面使用在Dirac-Hatree-Fock交换势下求解得到的Mott散射截面。计算了固体表面弹性背散射率随非弹性散射平均自由程(IMFP)的变化规律,利用弹性背散射率实验数据得到能量为100-2000 eV的电子IMFP。计算结果与使用原子广义振子强度模型得到的IMFP结果进行比较,两者符合较好。

Elastic backscattering probabilities for Fe, Cu, Ag and Au were calculated by Monte Carlo method. The Mott cross-section with Dirac-Hatree-Fock atomic potential was used to describe and calculate the elastic scattering electrons traversing in the solids. A function between assumed values of the electron inelastic mean free path （IMFP） and elastic backscattering probability for normal incidence of the electron beam was given by the Monte Carlo code. With the relation between the elastic backscattering probability and the IMFP in the solid, the IMFPs of Fe, Cu, Ag and Au with electron energy from 100 eV to 2000 eV were determined. And a comparison between the present method and atomic generalized oscillator strength （GOS） model showed that IMFPs calculated by the present method agreed well with those from the GOS model. It is therefore recommended that the M-C simulation be used for determining IMFP when elastic backscattering probability can be correctly measured.