Measurements Of K-shell Ionization Cross Sections Of Al And L-shell X-ray Production Cross Sections Of Se By KeV Electron Impact

As the basic research in atomic physics,the atomic inner-shell ionization cross-sections are of great importance in practical applications and theoretical researches.On the one hand,accurate atomic inner shell ionization cross-sections promote a better understanding of the interaction principle of positron/electron and matter.On the other hand,the cross-sections are fundamental data in many practical applications.Some elements are still lack of experimental data about electrons,such as the L-shell of Se element.For the newest theory DWBA,there are some differences between the experimental and theoretical values for different authors.Therefore,in order to supply the experimental data and further evaluate the existing theory,and promote the development of the theory,more experiments need to be done.The K-shell ionization cross sections of Al(Z=13)and the total L-shell x-ray production cross sections of Se(Z=34)by electron impacts with kinetic energies ranging from several keV to several tenths of keV have been measured.The works can be list as follows:(1)The K-shell ionization cross sections of a new Al target of monoatomic and grid carbon substrate,and of target of Al film deposited onto thick carbon substrate were measured to test the reliability of the new target.(2)Targets of Se film(?7.8 nm)deposited onto thick carbon substrate(?2mm)was measured.This is the first time that experimental data of Se-L-shell x-ray production cross sections in the intermediate-energy region have been published.(3)Considering the effect of the substrate on the experimental results,the correction of the thin film deposited onto thick carbon substrate targets cannot be neglected.Near the threshold energy,the experimental error caused by the target structure is considerable.In this paper,the Monte Carlo program PENELOPE was used to obtain the correction factors.The results show that the new target of monoatomic and grid carbon substrate is reliable in this research domain.Within the uncertainties,the DWBA agrees with our experimental measurements of K-shell ionization cross sections of Al and the total L-shell x-ray production cross sections of Se.Our measurements are also consistent with the available experimental data.In addition,this is the first time that experimental data of Se-L-shell x-ray production cross sections in the energy region 3.5 ke V~30 ke V have been published.