Variation of ionization with range of α-particles, protons, deuterons and ³H particles

Abstract

Photometrical determinations of the variation of density along photographs of expansion champer tracks have enabled the positions of maximum ionizing efficiency for single α-particles, protons, deuterons, and 3H particles to be determinated.The maximum rate of ionization for an α-particle in air occure when it has a residual range of 3·7 mm. in standard air.The distance of the position of maximum ionizing efficiency from the end of the particle range is shown to be approximately in the ratio of the particle mass in the case of the particles 1H, 2H, and 3H.These experiments were carried out in the Cavendish High Tension Laboratory.