20—50MeV O5+离子引起Au的L壳层X射线产生截面研究

在北京13 MV串列加速器上利用20—50MeV O⁵⁺离子研究Au的L壳层X射线产生截面. 实验结果表明σ（Ll）/σ（Lα） ,σ（Lβ）/σ（Lα） 和σ（Lγ）/σ（Lα）与EＣＰSSR理论计算结果符合比较好.在实验中由于较高的能量,在能量点存在能移现象. 关键词： 产生截面 ECPSSR X射线     

Measurement of ^16O^5＋ Induced L X-Ray Production Cross Sections for Gold

The characteristic L1, Lα, Lβ and Lγ x-rays of Au and energy shifts produced by 20-50 MeV ^16O^5＋ beams on a thick Au film are measured with a Si （Li） detector. Cross-section ratios of σ（Ll）/σ（Lα）, σ（Lβ）/σ（Lβ） and σ（Lγ）/σ（Lα） versus O^5＋ energy show that consistent calculations yield considerably better agreements. Energy shifts L1, Lα, Lβ and Lγ x-rays of Au target increase with more incidence energy. The main application for these measurements is multi-element trace analysis through particle induced x-ray emission.     

Cross sections of Oq+（q=1-4） electron loss in collisions with He,Ne and Ar

Electron-loss cross sections of O q+(q = 1 4) colliding with He,Ne and Ar atoms are measured in the intermediate velocity regime.The ratios of the cross sections of two-electron loss to that of one-electron loss R 21 are presented.It is shown that single-channel analysis is not sufficient to explain the results,but that projectile electron loss,electron capture by the projectile and target ionization must be considered together to interpret the experimental data.The screening and antiscreening effects can account for the threshold velocity results,but cannot explain the dependence of the ratio R 21 on velocity quantitatively.In general,the effective charge of the target atom increases with velocity increasing because the high-speed projectile ion can penetrate into the inner electronic shell of target atom.Ne and Ar atoms have similar effective charges in this velocity regime,but He atoms have smaller ones at the same velocities due to its smaller nuclear charge.