靶表面粗糙度对低能电子致厚Ni靶特征X射线产额的影响研究  

Effects of surface roughness on measurements of characteristic X-ray yields of thick Ni target by low-energy electron impact

作　　者：田丽霞 尹毅 戴朝成[3] TIAN Lixia;YIN Yi;DAI Chaocheng(School of Nuclear Science and Engineering,East China University of Technology,Nanchang 330013,China;Multidisciplinary Research Center,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;School of Earth Sciences,East China University of Technology,Nanchang 330013,China)

机构地区：[1]东华理工大学核科学与工程学院,南昌330013 [2]中国科学院高能物理研究所多学科研究中心,北京100049 [3]东华理工大学地球科学学院,南昌330013

出　　处：《核技术》2021年第11期20-24,共5页Nuclear Techniques

基　　金：国家自然科学基金(No.12075056、No.11505028)资助。

摘　　要：采用蒙特卡罗(Monte Carlo,MC)法对低能电子入射厚Ni靶时靶表面粗糙度对特征X射线产额的影响进行了模拟分析,结果表明:随着表面粗糙度的增大,其特征X射线产额逐步减小。采用扫描电镜装置测量得到了9~29 keV的电子束碰撞光滑厚Ni靶所致的K壳层特征X射线产额,通过与最新的扭曲波玻恩近似(Distorted Wave Born Approximation,DWBA)理论计算值对比表明,Kα特征X射线的实验产额与DWBA理论计算值吻合很好,Kβ特征X射线产额高于DWBA理论值约10%。因此,在今后的电子致厚靶原子内壳层电离截面实验中,需对实验靶样品表面进行镜面抛光,以减小表面粗糙度对实验结果的影响。[Background]Accurate measurements of characteristic X-ray yields of Ni by electron impact play an important role in electron probe and auger electron spectroscopy analysises of Ni materials.However,the surface roughness of thick Ni targets may adversely affect the accuracy of these measurements.[Purpose]This study aims to investigate surface roughness effects in the measurements of characteristic X-ray yields of thick Ni targets by low energy electron impact.[Methods]The surface roughness effects were simulated by using the Monte Carlo(MC)code PENELOPE-2008.A KYKY-2800B scanning electron microscopy was used for measurements of K-shell X-ray yields of a mirror polished Ni target by impact of 9~29 keV electrons.[Results]The MC simulation results indicate that the characteristic X-ray yield decreases with the increase of surface roughness.Comparisons between experimental data and the predictions of distorted-wave Born approximation(DWBA)theory show that the KαX-ray yields are in good agreement with the predictions,while for the Kβline,the X-ray yields are about 10%higher than the corresponding predictions.[Conclusions]It is necessary to do mirror polishing on the target surface in order to reduce the influence of surface roughness on measurements of inner-shell ionization cross sections of thick target by electron impact.

关 键 词：表面粗糙度 蒙特卡罗 特征X射线产额 

分 类 号：TL814[核科学技术—核技术及应用]