近玻尔速度氙离子激发钒的K壳层X射线  

Vanadium K-shell X-ray emission induced by xenon ions at near the Bohr velocity

作　　者：周贤明[1,2,3] 赵永涛[1,4] 程锐[1] 雷瑜[1] 王瑜玉[1] 任洁茹[1,3] 刘世东[1,3] 梅策香[4] 陈熙萌[2] 肖国青[1] 

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]兰州大学核科学与技术学院,兰州730000 [3]中国科学院大学,北京100049 [4]西安交通大学理学院,西安710049

出　　处：《物理学报》2016年第2期336-341,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11275241;11505248;11205225;11375034;11105192;11275238);陕西省教育厅科研计划(批准号:14JK1803;15JK1793)资助的课题~~

摘　　要：测量了2.4—6.0 MeV Xe^(20+)离子轰击V靶表面过程中辐射的X射线.计算了V的K壳层X射线发射截面,并将实验结果与平面波恩近似、ECPSSR、两体碰撞近似的理论计算进行了对比.讨论了近玻尔速度非对称碰撞过程中,BEA模型估算高电荷态重离子激发内壳层电离的修正因素.结果表明,综合考虑库仑偏转和有效电荷态修正后,BEA理论与实验结果符合较好.The X-ray emission spectra produced by 2.4-6.0 MeV Xe20＋ ions impacting on vanadium surface were measured. The V K-shell X-ray production cross sections were extracted from the experimental yield data and compared with the theoretical predictions of the binary encounter approximation （BEA）, the plane wave born approximation （PWBA）, and the energy-loss coulomb-repulsion perturbed-stationary-state relativist （ECPSSR）. In order to predict reasonably the inner-shell ionization induced by highly charged heavy ions during the asymmetric collisions at near the Bohr velocity, the corrections of BEA model are discussed. It is found that the X-ray production cross section induced by highly charged heavy ions moving at near the Bohr velocity is on the magnitude of 1 barn, which is almost four orders of magnitude larger than that induced by proton. The ECPSSR, which is regarded as the best model to simulate the inner-shell ionization by light ions, may underestimate the experimental data at least three orders of magnitude. The PWBA model presents a prediction to the＇results on an order of magnitude better than the ECPSSR simulation, but gives a worse tendency than the BEA model. The BEA calculations, corrected both by Coulomb repulsion and effective nuclear charge, present the best agreement with the experimental results. It is proposed, that in the energy region near the Bohr velocity, during the asymmetric collisions of Xe20＋ ions with V atoms, the K-shell electron of V is ionized by direct ionization, and that it can be described by the binary encounter process between the xenon ions and the bound electrons. The X-ray production cross section can be simulated by BEA model, but the corrections of Coulomb repulsion and effective nuclear charge must be considered.

关 键 词：高电荷态重离子 X射线 两体碰撞近似 有效电荷 

分 类 号：O434.1[机械工程—光学工程]