数百MeV/u高能区C^(6+)离子激发W的L壳层X射线  

W L-shell X-ray emission induced by C^(6+) ions with several hundred MeV/u

作　　者：周贤明 尉静 程锐[2] 梅策香[1] 曾利霞[1] 王兴[3] 梁昌慧[1] 赵永涛[2,3] 张小安[1,2] Zhou Xian-Ming;Wei Jing;Cheng Rui;Mei Ce-Xiang;Zeng Li-Xia;Wang Xing;Liang Chang-Hui;Zhao Yong-Tao;Zhang Xiao-An(Ion beam and Optical Physics Laboratory,Xianyang Normal University,Xianyang 712000,China;Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China;School of Science,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]咸阳师范学院,离子束与光物理实验室,咸阳712000 [2]中国科学院近代物理研究所,兰州730000 [3]西安交通大学理学院,西安710049

出　　处：《物理学报》2022年第11期127-135,共9页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2017YFA0402300);国家自然科学基金(批准号:11505248,11775042,11875096);陕西省科技厅科研计划(批准号:2021JQ-812);陕西省教育厅科学研究计划(批准号:20JK0975);咸阳师范学院学术带头人(批准号:XSYXSD202108)和咸阳师范学院重点培育项目(批准号:XSYK21037)资助的课题

摘　　要：在能量为154—424 MeV/u的高能区域,研究了C^(6+)离子轰击W靶时激发W的L壳层X射线.本文中,由于L X射线发射时M,N等外壳层处于多空穴的状态,观测到了相应谱线能量的蓝移,以及分支L_(ι),Lβ_(1,3,4),Lβ_(2,15)与Lα_(1,2) X射线相对强度比的增大.另外,利用优化的厚靶截面公式,并考虑多电离对X射线荧光产额的影响,计算了L X射线的发射截面,并与平面玻恩近似(PWBA),经能量损失(E)-库仑排斥(C)-稳态微扰(PSS)-相对论(R)修正的PWBA理论(ECPSSR)和两体碰撞近似(BEA)理论计算结果进行了对比.分析表明,在本实验能区内ECPSSR对PWBA的修正作用可以忽略,两者计算结果几乎相同且均大于实验截面;BEA估算整体上与实验结果符合较好.The L-shell X-ray emission of tungsten is investigated under the bombardment of C^(6+)ions in a high energy range of 154—424 MeV/u.Compared with the atomic data,the energy of the X-ray is enlarged,and the relative intensity ratio of L_(ι),Lβ_(1,3,4) and Lβ_(2,15) to Lα_(1,2) X-rays are enhanced.The L-subshell and the total X-ray production cross section are calculated from a well corrected thick target formula and compared with the theoretical estimation of binary encounter approximation(BEA),plane-wave Born approximation(PWBA)and ECPSSR(PWBA theory modified with Energy-loss,Coulomb-repulsion,Perturbed-Stationary-State and Relativistic corrections).On the whole,the experimental cross sections are all smaller than the prediction of PWBA and ECPSSR,but in rough agreement with that of BEA.It is indicated that the inner-shell ionization of W can be considered as a binary process between the high energy C^(6+)ions acting as a point charge and the independent target electrons.With the L-shell ionization,the outer-shells are multiply ionized.The multi-ionization degree is approximately regard as a constant in the present work.This leads the X-ray energy to be blueshifted and the relative intensity ratios of L_(ι)and Lβto LαX-ray to be enhanced.Using the atomic parameters corrected by multi-ionization,the X-ray production cross section can be estimated by the BEA model.

关 键 词：高能重离子 离子-原子碰撞 多电离 X射线 

分 类 号：O571.6[理学—粒子物理与原子核物理]