LXXI. The abundance of lithium, beryllium, and boron in the primary cosmic radiation

Abstract

Summary In a previous paper, a method of determining the charge, of heavy nuclei in the cosmic radiation was described which depended on measuring the δ-ray density along a track in a photographic emulsion and the multiple scattering of the particle. The results suggested the presence of a large proportion of the light elements lithium, beryllium and boron in the radiation, a result in contradiction with that of other workers. The first part of the present paper describes a re-examination of the original method and evidence for its reliability. It is shown that an alternative method, based on observations of grain-density in the tracks of heavy particles recorded in less sensitive emulsions, gives results in agreement with those obtained by the δ-ray method. In the second part, the results of a more extended series of measurements by the, δ-ray method are described. The results indicate that at geo-magnetic latitude 55° N., the flux of lithium, beryllium and boron nuclei in the cosmic radiation is equal t...