光电离过程中Fe靶和V靶特征辐射的角相关研究  

Angular distribution of characteristic X-ray emission from Fe and V following photoionization

作　　者：柳钰 徐忠锋[1] 王兴[1] 曾利霞[2] 刘婷[2] Liu Yu;Xu Zhong-Feng;Wang Xing;Zeng Li-Xia;Liu Ting(School of Science,Xi’an Jiaotong University,Xi’an 710049,China;Ion Beam and Optical Physical Laboratory,Xianyang Normal University,Xianyang 712000,China)

机构地区：[1]西安交通大学理学院,西安710049 [2]咸阳师范学院与中国科学院近代物理研究所联合共建离子束与光物理实验室,咸阳712000

出　　处：《物理学报》2020年第4期97-102,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11875219,11405123);陕西省科技厅自然科学基础研究计划(批准号:2019JQ-493);陕西省教育厅科研计划(批准号:19JK0928);咸阳师范学院自然科学基金(批准号:XSYK17008)资助的课题~~

摘　　要：在发射角120°—170°的范围内,应用硅漂移探测器以10°为间隔对中心能量为13.1 keV的韧致辐射诱发Fe靶和V靶发射的典型K系X射线光谱进行了测量.得到特征X射线Kα和Kβ的特征谱线,考虑探测器对特征X射线的探测效率、靶对入射光子和出射光子吸收的校准及大气对特征X射线的吸收后,结果显示不同探测角度下Kβ与Kα的强度比为一常数.将本次实验探测角度为150°时的Kβ/Kα强度比值的实验值、理论计算值和Ertuğral的实验结果进行对比,发现实验结果与预期相符.对比不同探测角度下的强度比变化趋势推断特征X射线的角度依赖关系,分析认为Kα和Kβ在探测范围内是各向同性发射的.The de-excitation process of vacancy in the inner shell of the target atom caused by collision ionization produces the characteristic X-ray or Auger electrons.The precise measurement of ionization cross sections plays an important role in many basic research fields,as well as in practical fields,such as chemical analysis of Particle Induced X-ray Emission(PIXE),atomic and nuclear processes,and X-ray fluorescence(XRF)spectroscopy.As we know,when ionization cross sections are measured precisely,whether the emission of X-ray is isotropic in collision process must be considered.However,there have been few experimental results for angular dependence of Kb/Ka intensity ratios in the literature until now.Therefore,this study aims to verify that the Ka and Kb X-rays originated from filling of the K shell vacancies with total angular momentum quantum number 1/2(J=1/2)are isotropic.In this work,the typical K-shell X-ray spectra for Fe and V,which induced by bremsstrahlung with central energy of 13.1 keV,have been measured at emission angles varied from 120°to 170°at intervals of 10°.The characteristic X-ray spectra obtained by the detector are fitted by Gauss function,where the absorption of incident X-rays by the detector,the absorption of emitted X-rays by the atmosphere and the self-absorption correction factor of incident and emitted X-rays by the target are all taken into account.The experimental results of Kb/Ka intensity ratio in this experiment coincide with those of theoretical calculation,as well as the Ertuğral’s experimental result.The experimental results show that the intensity ratio of Kb/Ka is a constant at different detection angles.Therefore it can be concluded that the emission of Ka and Kb is isotropic in the detection range.Since the K shell has no sub-shell,there is no Coster-Kronig transition in the collision ionization process.In the process of photoionization,the vacancies in the K shell are produced by direct ionization.As a result,the cross section ratio of K shell X-ray generation is indep

关 键 词：角分布 光电离 各向同性 

分 类 号：O572.212[理学—粒子物理与原子核物理]