H^+和Ar^(11+)激发Si的K壳层X射线发射研究

Study of Si K-shell X-ray emission induced by H^+ and Ar^(11+) ions

测量了50—250keV H+和1.0—3.0MeV Ar11+轰击Si表面过程中辐射的X射线.结果表明,在Ar11+入射的情况下,引起了Si的L壳层上3,4个电子的多电离.计算了Si的K壳层X射线产生截面,并将两体碰撞近似(BEA),平面波恩近似,ECPSSR理论计算与实验值进行了对比.ECPSSR理论与质子产生的截面数据能够很好地符合;而考虑多电离后,BEA理论与Ar11+的实验结果符合较好.

The L-shell X-rays of Si, induced by 50-250 keV proton and 1.0-3.0 MeV Ar^11＋ ions impacting are measured. It is found that the X-ray induced by Ar^11＋ is about 36 eV higher than that induced by proton. That indicates that 3, 4 L-shell electrons of Si atom are multiply-ionized by Ar^11＋ ion impact. The X-ray production cross section is extracted from the yield data and compared with the results from the BEA, PWBA and ECPSSR models. With the same unit incident energy, the cross section induced by Ar^11＋ is about 3 orders of magnitude larger than that produced by proton. For proton impact, the ECPSSR model gives an accurate prediction to the cross section data. However, the BEA model, considering the change of fluorescence yield due to the multiple-ionization, presents the results that are in better agreement with the experimental results for Ar^11＋ ions.