MEASUREMENTS OF TOTAL CROSS SECTIONS FOR K－SHELL IONIZATION BY ELECTRON BOMBARDMENT

ＭＥＡＳＵＲＥＭＥＮＴＳＯＦＴＯＴＡＬＣＲＯＳＳＳＥＣＴＩＯＮＳＦＯＲＫ－ＳＨＥＬＬＩＯＮＩＺＡＴＩＯＮＢＹＥＬＥＣＴＲＯＮＢＯＭＢＡＲＤＭＥＮＴＬｉＪｉｎｇｗｅｎ（李景文）；ＤｏｎｇＺｈｉｑｉａｎｇ（董志强）；ＺｅｎｇＸｉａｎｔａｎｇ（曾宪堂），Ｈ...     

CORRECTION OF INFLUENCE OF SUBSTRATE ON MEASUREMENT OF INNER SHELL IONIZATION CROSS SECTIONS

The energy spectra of reflected electrons from the substrates of targets have been calculated by the bipartion model of electron transport,the contributions of the inner shell ionization events produced by the reflected electrons from the substrates in the targets to the x-ray counting in a Si(Li) detector have been estimated.It has been confirmed that,by such correction to the measured data.the experimental results of inner shell ionization cross sections by electron impact with fine precision may be obtained under the conditio of thick substrate.     

Measurement of Sc and V K—shell ionization cross sections by slow electron impact

Electron-induced Sc and V K-shell ionization cross sections,which are scarce have been obtained from measurement of KαX-ray emission cross sections at energies from near threshold to 25keV.The influence of substrate of thin targets on ionization cross sections has been corrected using the bipartition model of electron transprot.     

CALCULATION OF ELECTRON-IMPACT IONIZATION CROSS SECTIONS FOR ATOMS AND IONS WITH HIGH Z BY LOTZ FORMULA

The experimental and theoretical study of electron-impact ionization pro-cesses in atomic system not only extends our understanding of atomic structureand collision dynamics but also is important for applications in the research onfusion and laser plasmas.Ionization theory is much more difficult thanexcitation theory,since there are two free electrons to consider,the ejected elec-tron and the scattered one after an ionizating collision.But the results obtainedby various approximations are in better agreement with the experimental datafor ionization than for excitation.     

用薄靶厚衬底方法测量电子碰撞引起的K壳层电离截面

用能谱仪测量特征X射线,从而导出元素钛和钒的K壳层电离截面。为克服制靶困难,实验中采用薄靶厚衬底方法。通过电子输运计算,由厚衬底产生的反射电子对计数的影响得以修正。将结果和Green等的半经验公式以及Jessenberger等的测量数据进行了比较。     

Measurement of 8—25keV electron impact K—shell ionization cross sections of Cu and Co elements

The influence of substrate of thin targets on ionization cross sections has been corrected by a new method based upon the bipartition model of electron transport.The measured cross sections for Cu element are in good agreement with existing experimental data and those produced by the empirical formula of Green and Cosslett.Cross sections for Co element are measured for the first time.