Cosmic Ray Nuclear Interactions in Nitrogen GaS

Abstract

The natural rate of occurence of nuclear interactions of cosmic ray N-component in which more than 5 Mev are given to charged secondary particles have been measured in the nitrogen filled high pressure cloud chamber at Mt. Norikura (2840 m above sea level and 25°N geomagnetic latitude). From the rate of occurence of number interactions, the vertical intensity of N-component was estimated at (2.4±4%)·10 -3 ·E -1.4 cm -2 s -1 sr -1 Mev -1 for the energy range from 10 Mev to 100 Mev by assuming the geometrical cross section. These events may be considered to be the source of the cosmic ray N-component with an energy less than that sufficient to produce nuclear interactions in the atmosphere, and it was shown that the spectrum of secondary particles was in accord with that of the latter. The absolute intensity of N-component was also consistent with that expected from the data of other energy regions in our previous paper. A possible scheme of the nuclear cascade was discussed in relation to the size distribution of the observed stars.