The L shell ionisation cross section of atoms by relativistic electron

Recently Sud and Sharma (1982) have calculated the K-shell ionisation cross section of atoms by electron impact using Plane Wave Born Approximation (PWBA). The method is a modification of Kolbenstvedt's impact parameter theory. The PWBA calculation is performed by using the virtual photon concept of Williams and Weizsacker. In this concept the interaction between incident and atomic electrons is mediated by the equivalent spectrum of virtual photons. The ionisation cross section is expressed as a folding integral of virtual photon spectrum with the photoionisation cross section of the atomic shell. Here, the L-shell ionisation cross section by using the Scofield photoionisation cross section and PWBA expression for virtual photon spectrum has been calculated. The L-shell ionisation cross section calculated by using the PWBA method for different Z-values and for electron impact energies ranging from near threshold to 100 MeV are presented. The results of calculation are compared with the available experimental and theoretical results. (author). 4 figs., 21 refs