Investigation on X-rays and β-rays by the cloud method. Part II.—β-rays

Abstract

The greater part of the material used in the study of the β-ray tracks was obtained during the experiments with X-rays described in Part I. A number of photographs were also taken of the tracks of fast β-particles emitted by radio-active substances or ejected from the walls of the cloud chamber by γ-rays. Some photographs of α-ray tracks were obtained during the course of these experiments; these have been published elsewhere. 1. General Character of β-ray Tracks . The tracks of the fastest β-ray particles in air are generally perfectly straight over distances of many centimetres. Within the last 10 cms. of its range the deviations in the path of a β-ray are very marked and become more and more so as the velocity of the particle diminishes. Fig. 1 (Plate 16) shows in a striking way the contrast between the paths of fast and slow β-particles.