A Method of Photographing the Disintegration of Atoms and of Testing the Stability of Atoms by the Use of High-speed Alpha Particles

Abstract

WHILE the experimental work of Rutherford demonstrates the disintegration of the nuclei of the atoms of six elements of odd atomic number to give long-range hydrogen nuclei, it does not show whether shorter-range products of disintegration are emitted. It occurred to one of the writers several years ago that the photographic method of C. T. R. Wilson would be the best means easily available of actually testing the stability of the nuclei of atoms for the different types of disintegration, particularly when the particles emitted have a short range. In the earlier applications of this method polonium has been used almost exclusively as the source of -particles. The -particles thus emitted have a relatively small kinetic energy, so the evidence obtained from the photographs is not of much value in its bearing on nuclear stability. The writers have therefore used the high - speed -particles from thorium C, with a velocity of 2.05 × 10⁹ cm./sec., or 0.688 c.