Several methods for determining the charge and energy of heavy nuclei found to be present in the primary cosmic radiation, are discussed. The application to a number of tracks of the heavy primary cosmic-ray component in Ilford C₂ emulsions shows the presence of nuclei from the neighborhood of carbon in the periodic system up to the neighborhood of iron (Z2030). A nuclear explosion caused by the collision of a 3-Bev carbon or oxygen nucleus with a silver nucleus of the emulsion is discussed. It is shown that both the magnitude of the flux and the distribution of ranges of the nuclei of the heavy primary cosmic-ray component may give valuable information regarding the origin of cosmic rays.
Bradt et al. (1948) studied this question.