Cosmic ray radiation effects caused by proton-induced fragmentation

Abstract

In space, radiation effects in which a large amount of energy is transferred by a single particle are observed. These effects can be caused by either the direct ionization of a cosmic ray heavy ion or alternatively by the ionization of short range target fragments which are produced inside the material by interactions of cosmic ray particles. Protons of the lower radiation belt contribute significantly to target fragmentation; especially in the South Atlantic Anomaly (SAA). To allow predictions of possible radiation hazards the characteristics of these interactions at energies below 100 MeV must be understood in detail. We have performed an experiment to measure the proton induced fragmentation cross sections for carbon target nuclei at about 70 MeV/nucleon and to determine some characteristics of the kinematics of the target fragments. For this purpose experimental setups with CR-39 track detectors were used. In this paper we describe the experimental technique and present some preliminary results.