The Space-Distribution of the Photo-Electrons Ejected by X-Rays

The experiments of Wilson, Auger, Bothe, Bubb, Loughridge and Kirchner by the C. T. R. Wilson cloud expansion-chamber method have shown that while the most probable direction of the photo-electron tracks in a gas traversed by X-rays is nearly the direction of the electric vector of the incident radiation, there is apparently a very considerable "spread" in the direction of the tracks. Magnetic spectra of the electrons ejected from very thin metallic films at various angles show similar effects. Theories to account for this apparent emission from the atom over a wide range of angles instead of in one definite direction have been given by Bubb, Bothe, Auger and Perrin, Wentzel and Beck, but none of them is satisfactory in explaining all the now known experimental facts. The purpose of this paper is to point out that nuclear scattering of the sort postulated by Rutherford with such brilliant success in the case of α-particles has not been sufficiently considered in this connection and that it probably will account for the whole effect.