The transition effect of star-producing radiation

Abstract

By the method of the sensitive emulsion we confirmed the transition effect of nuclear stars, i. e. the increase in their number under layers of a few centimetres of lead with the main maximum exceeding by 15% under 2 cm of lead. With disintegrations having an excitation energy U>200 MeV we observed a tendency to a second maximum under greater thicknesses of lead. We also found that the character of the absorption of the individual tracks (due to “protons”) is similar to the absorption curve of stars, the difference being that the maximum under 2 cm of lead is even by 34% above the exponential decrease. We consider as most probable that the main maximum of the stars having excitation energies U<200 MeV is caused by the photon component of cosmic rays while the anomalous increase in the number of disintegrations having energies U>200 MeV is due to fast neutrons. It was not possible to estimate the contribution of mesons from the given experimental material.