Capture of Electrons by α-Particles in Hydrogen

Abstract

THE phenomenon discovered by Henderson (Proc. Roy. Soc., 102, 496, 1922) of the capture of electrons by particles passing through matter has attracted much interest and has been subjected to theoretical investigation from various sides. By comparing the statistical equilibrium between capture and loss of electrons by α-particles with an equilibrium of thermal dissociation, Fowler (Phil. Mag. 47, 416, 1924) was able to account for many of the characteristic features of the phenomenon revealed by Rutherford's careful examination (Phil. Mag. 47, 277, 1924); in particular, for the fact that the ratio between the probabilities of capture and loss for particles of given velocity was nearly the same in all substances investigated and varied approximately as the fifth power of the velocity.