Some remarks concerning the energy dependence of the intensities of nuclei of helium-3, lithium, beryllium and boron in the galactic cosmic radiation

Abstract

Available experimental data on the energy dependence of the production cross sections of some favourable light nuclei from spallation reactions of protons with typical cosmic ray nuclei, have been examined. The analysis focuses attention on the necessity of determining accurately cross sections for the production of isotopes of light nuclei from various targets at low bombarding energies; this is necessary for the proper understanding and interpretation of the primary cosmic radiation. The calculations show that in the galactic cosmic radiation (i) the deuterons produced from spallations constitute only a very small proportion of singly charged particles, where as the proportion of He³ among doubly charged particles is large enough to be detected experimentally with techniques in use at present, (ii) the production rate of He³ is energy dependent and can be employed to deduce information on the history of the radiation and (iii) the amount of matter traversed by the radiation during the time of its acceleration from about 20 MeV/n to about 100 MeV/n is much less than 2.5 g/cm² of hydrogen.