An empirical formula of atomic K-shell ionization cross sections by electron impact

An empirical formula is proposed to describe the K-shell ionization cross s ections by electron impact over a wide range of atomic numbers and overvolt ages U (the ratio between the electron incident energy and the binding ener gy of the electrons in the K-shell). The study is based on the analysis of existing experimental data of K-Shell ionization cross sections. The expres sion shows the results in good agreement with the data for Z < 6 atoms as w ell as for 6 less than or equal to Z less than or equal to 79.