Investigation of the Primary Cosmic Radiation with Nuclear Photographic Emulsions

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.