Nuclear Disintegrations Produced by Cosmic Rays

Abstract

SINHA has recently published¹ a remarkable cloud-chamber photograph of a four-pronged disintegration of an oxygen nucleus produced by a neutral cosmic ray particle. From the appearance of the tracks, he concludes that the two outer ones (tracks 1 and 4) are due to particles of a charge higher than that of an α-particle. The two inner tracks (2 and 3) appear to be due to doubly charged particles. Their end portions are crossed by thin ionization tracks. After considering the possibility that this is due to an extremely rare chance coincidence, Sinha suggests that the thin tracks may be interpreted as pairs of (oppositely charged) electrons emitted from excited nuclei at the end of their paths. He emphasizes, though, that it is difficult to understand why the electrons should be emitted in diametrically opposite directions.