Inner-shell Ionization Of Atom Induced By1.0MeV Electron Bombardment

The study of atomic inner shell ionization by electron impact is one of the mostimportant topics of atomic physics. Up to now, most of the experimental inner shellcross section data were mainly concentrated on the low and medium Z target atoms bythe bombardment of low energy electrons, and there were still significantdiscrepancies between present experimental data from different groups. On the otherhand, theoretical models could not explain all the related inner shell ionization dada ofthe various target atoms induced by electrons with different energies. More accurateexperimental data are still strongly required both to test the theoretical models, and tounderstand the collisional mechanism of electrons with atoms further.The experiment was carried out on the electron accelerator at the Institute ofModern Physics, Chinese Academy of Sciences, using self-supported thick target. TheK-shell ionization cross sections of Ni, Cu, Zi, Zr, Nb, Mo, Pd, Cd, Sn, Ta, Re and Auand L-shell ionization cross sections of Ta and Au are measured for1.0MeV electronbombardment. The measured data were compared with the calculated results of theempirical models and the available experimental data from other groups.The present K shell ionization cross sections were compared with the results ofSBELL, Hombourger and Casnati empirical models, and the measured K shellionization cross sections of Sn and Au were compared with the experimental datameasured by D. H. Rester and W. E. Dance. The L shell ionization cross section of Taand Au were compared with the calculations of Born-Bethe and Scofield models. It is found that the present K shell ionization cross section of low Z target atoms aresmaller than the predictions of the empirical models, and for high Z target, the K-andL-shell ionization cross sections obtained in present work are in reasonable agreementboth with the theoretical predictions and with the previous experimental data.