近Bohr速度I20+离子在不同靶面上的L壳层X射线辐射  

I L-shell X-rays from near Bohr-velocity I20+ions impacting on various targets

作　　者：周贤明[1,3] 尉静 程锐 赵永涛[2,3] 曾利霞[1] 梅策香[1] 梁昌慧[1] 李耀宗[1] 张小安[1,2] 肖国青[2] Zhou Xian-Ming;Wei Jing;Cheng Rui;Zhao Yong-Tao;Zeng Li-Xia;Mei Ce-Xiang;Liang Chang-Hui;Li Yao-Zong;Zhang Xiao-An;Xiao Guo-Qing(Ion Beam and Optical Physics Joint Laboratory of Xianyang Normal University and Institute of Modern physics,Chinese Academy of Sciences,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 [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》2021年第2期323-329,共7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);陕西省教育厅专项科研计划(批准号:20JK0975);陕西省科技厅自然科学基础研究计划(批准号:2020JM-624)资助的课题.

摘　　要：在兰州重离子加速器国家实验室,利用硅漂移X射线探测器探测了4.5 MeV I20+离子入射到Fe,Co,Ni,Cu,Zn靶表面时产生I的L壳层X射线.实验观察到Ll,Lα1,2,Lβ1,3,4,Lβ2,15,Lγ1,Lγ2,3,4,4,等6组分辨较好的谱线,各分支X射线的能量发生了蓝移;Lβ1,3,4,Lβ2,15与Lα1,2谱线的相对强度比随靶原子序数的增大基本线性增加,Ll与Lα1,2,Lγ2,3,4,4,与Lγ1 X射线的相对强度比近似与靶原子序数的平方成正比.分析表明,玻尔速度附近能量的低速高电荷态离子与固体靶原子碰撞产生的内壳层过程存在直接库仑电离和电子俘获的双重综合作用,这使得内壳层X射线发射时,外壳层仍存在多个空穴,导致辐射X射线的频移和分支比的变化.The L-shell X-ray emissions of iodine are investigated as a function of target atomic number for 4.5-MeV I20+ions impacting on Fe,Co,Ni,Cu and Zn targets.Six distinct L-subshell X-rays are observed.The energy of the x-ray has a blue shift compared with the atomic data.The relative intensity ratio of Lβ1,3,4 and Lβ2,15 to Lα1,2 almost increase linearly with the target atomic number increasing.The ratio of I(Ll)to I(Lα1,2 and I(Lγ2,3,4,4’)to I(Lγ1)are approximately proportional to the square of target atomic number.It is indicated that during the interaction of highly charged heavy ions with atom in the energy region near the Bohr velocity,the inner-shell process is mainly caused by the close-range collisions below the surface.There,the projectile not only has enough time to capture electrons from the target atom to be neutralized,but also has enough kinetic energy to ionize the inner-shell electron by coulomb interaction.At the balance between electron capture and ionization,the outer-shells of M,N,O etc.could be multiply ionized.The extent of multiple ionization increases with the target atomic number increasing.That leads to the energy shift,resulting in the change of the relative intensity ratio for the L-subshell X-ray.The smaller the atomic fluorescence,the larger the enhanced fluorescence caused by multiple ionization.

关 键 词：离子原子碰撞 X射线 多电离 

分 类 号：TL816.1[核科学技术—核技术及应用]