The Measurement Of High Z Atomic L、M-Shell Ionization Cross-sections Impact By Low Energy Electron

The measurement of atomic inner shell ionization cross section by low-energy electron impact is important both in theoretical researches and practical application. Reliable experimental data of inner-shell ionization cross sections by electron impact can promote the development of electron-atomic impact theoretical model.Also the data are widely needed in many branches of physics.There are still many blanks of atomic experimental data, and gap between the experimental results from different authors investigation.The experimental research of atomic inner shell ionization cross sections by low-energy electron impact main jobs as follows:1.The detection efficiency calibration of Si(Li) detector.The detection efficiency of the detector used in this paper was better than Si(Li) detector which was used extensively.As it is difficult to obtain the reliable detection efficiency calibration in low-energy region down to several keV.Here we carried out it by using SDD detector,measuring the bremsstrahlung spectrum of thick carbon target by 19keV electron beam,and theoretical calculation of thick carbon target bresstrahlung spectrum by using PENELOPE program.The shape of the efficiency calibration curve was determined from the ratio of the experimental and theoretical thick carbon target bremsstrahlung spectra.And using the absolute efficiency calibration on 11.87keV and 13.95keV of 241Am standard point source to absolutize the relative efficiency calibration curve.Final can get the absolute efficiency calibration curve.2.Correct computation caused by thin film on thick target structure in characteristic X ray counting.We used PENELOPE software version 2005 simulating the process of electronic impact with target which the structure is thin layer on thick carbon target.In order to know how extent of the influence caused by target structrue the.3.Renew the software ionization cross section database.The database of the software refered by ODM database. Renew the software ionization cross section database up to DWBA using Fortran language programming.4.Due to the lack of the experimental data of the atomic inner shell ionization cross sections, especially the lack of M shell ionization cross sections, this paper work about measuring the L-shell X-ray production cross section of W,Ta,Ir,Pt, Au atomic. The results were well compared with DWBA theoretical model which is more recognition recent years..And M-shell X-ray production cross sections of the Pt and Au were well compared with DWBA only when the energy of electron more than 10 keV,but 30%-50% lower than DWBA theory when the energy of electron less than 10keV.Pt was first measured.