SIMPLE THEORY FOR K IONIZATION BY RELATIVISTIC ELECTRONS.

The total cross section for ionization of K‐electrons by electrons has been derived using the method of virtual photons combined with the photoelectric cross section for distant collisions and the Mo/ller cross section for close collisions. Good agreement with experiments is obtained for the elements silver (Z = 47) and tin (Z = 50) when the electron energy is much higher than the ionization energy.