近Bohr速度O^(4+)离子穿过H_(2)后的电荷态分布  

Charge State Distribution for O^(4+)Ions with Energy near Bohr Velocity Passing Through H_(2)

作　　者：尉静 周贤明 曾利霞[1] 梅策香[1,3] WEI Jing;ZHOU Xianming;ZENG Lixia;MEI Cexiang(School of Physics and Electronic Engineering,Xianyang Normal University,Xianyang 712000,Shaanxi,China;School of Science,Xi’an Jiaotong University,Xi’an 710049,Shaanxi,China;Laboratory of Physics and Chemistry Material Under Extraordinary Conditions,Northwestern Polytechnical University,Xi’an 710082,Shaanxi,China)

机构地区：[1]咸阳师范学院物理与电子工程学院,陕西咸阳712000 [2]西安交通大学理学院,陕西西安710049 [3]西北工业大学超常条件材料物理与化学教育部重点实验室,陕西西安710082

出　　处：《咸阳师范学院学报》2021年第4期23-28,共6页Journal of Xianyang Normal University

基　　金：国家自然科学基金项目(11505248,11775042,11875096);陕西省教育厅科学研究项目(20JK0975);陕西省科技厅科研计划项目(2020JM-624);超常条件材料物理与化学教育部重点实验室开放课题(MPCEC201901)。

摘　　要：基于两体碰撞近似的BEA模型和电子俘获的OBK模型,利用蒙特卡罗的方法计算了0.1~10倍玻尔速度的O^(4+)离子穿过长度为20 cm的H2气体靶后的电荷态分布情况。分析结果表明:5×1014 cm^(-3)是出射离子电荷态升高的临界密度,在此之前,电荷态的变化主要是降低;在此之后,还出现了升高的电荷态。随着靶密度的增加,升高电荷态的比例增大。同一靶密度下,平均出射电荷态随入射离子速度的增大而增加。10 v0的O^(4+)离子穿过5×10^(18)cm^(-3)的靶后全裸离子的比例可达93%。这为提高加速器出射离子的电荷态提供了重要的理论参考。Based on the model of BEA for direct coulomb ionization and OBK for electron capture,the distribution of charge state for 0.1~10 v0 O^(4+)ions passing through gaseous target of H2 with length of 20 cm was simulated using the method of Monte Carlo Code.The result indicates that the critical density of charge state increase is about 5×10^(14)cm^(-3).For na<5×10^(14)cm^(-3),the inner-shell process is dominated by electron capture,and the performance of charge-changing is mainly the elevation of the charge state.When na>5×10^(14)cm^(-3),ionization cross section is larger than that of capture,the charge-changing is mainly dwindled.The proportion of elevated charge state is increased with the increase of target density and incident ion velocity.The proportion of bare ions can reach 98%for 10 v0 O4+passing through target with density of 5×10^(18)cm^(-3).This provides an important reference for improving the charge state of ions from accelerator.

关 键 词：近玻尔速度 高电荷态离子 库仑电离 电子俘获 电荷态变化 

分 类 号：O562.5[理学—原子与分子物理]