The β-particle emission of radium D

Abstract

The main object of this investigation was to obtain an energy distribution curve for the electrons emitted by radium D during its disintegration. Such a distribution curve may be expected to be made up by the electrons coming from the nucleus, which have a continuous distribution of energy, together with secondary particles forming groups of homogeneous energy, produced by the action of the single γ-ray of radium D. The nuclear electrons are of great interest because owing to their very low energy they have never been identified with any certainty. The energy distribution finally obtained is shown in fig. 4, each point on the curve representing the number of particles having energies lying within 1000 volts on either side of the point. A secondary object of the work was to attempt to estimate the absolute number of particles emitted per disintegration, which number should, of course, be unity for the nuclear particles and some fraction less than unity for the secondary groups. The latter are due to the ejection of electrons from the L and outer atomic levels only, since the energy of the γ-ray, 47,200 volts, is insufficient to ionise the K level.