The Nature of the Cosmic Radiation

Abstract

On a view which regards the primary cosmic radiation as of charged corpuscular nature, it seems quite customary to regard the situation as one in which rays of a wide range of energy enter the atmosphere, pass through losing energy continually until they have completed their range, when they stop. If cosmic-ray intensity is measured by the number of rays per square centimeter per second per unit solid angle, or by something proportional thereto, the increase of cosmic-ray intensity with altitude is then ascribed to a situation in which the softer rays are more numerous in amount and describe shorter ranges. It is the custom to conclude, therefore, that the average radiation gets softer with increase of altitude. The purpose of this paper is to show that the foregoing view is completely erroneous and that if the distribution of energy of the incoming rays is adjusted so as to give an exponential law, then the quality of the radiation is independent of altitude. In other words, the radiation at some altitude above sea level is obtainable from that at sea level by simply increasing in the same proportion the numbers of all of the rays of varying energies. The situation is, therefore, one which seems quite incapable of accounting for the fact that nuclear bursts in lead produced by the primary radiation increase in number with altitude far more rapidly than the intensity of the cosmic radiation itself.