The Direction of Ejection of X-Ray Electrons

Abstract

No conclusive evidence that the direction in which photo-electrons are ejected by X-rays depends in any way upon the nature of the atom from which the ejection takes place has as yet been brought forward. Auger, using the C. T. R. Wilson cloud expansion-chamber method, showed that the most probable direction of ejection in a gas is a function of the frequency of the incident X-rays, but the variations which he found in this most probable direction with the nature of the gas used (oxygen or nitrogen, argon, krypton, xenon) were probably less than the experimental error, particularly as heterogeneous X-rays were used and the frequency of the X-rays which were most effective in ejecting electrons may have varied from gas to gas. Loughridge concluded that the most probable direction of ejection was the same for water-vapor, air and argon, but the absorption energies of even the K-shells of all these atoms is so small that at best only a small effect would be expected in these cases. Bothe using the point-discharge ion-counter made observations on air and on gases the molecules of which contained I, Br and Cl atoms. His results show small variations with the nature of the gas, but again as heterogeneous X-rays were used and his maxima were not sharp the variations were probably less than the experimental accuracy.