Nuclear Mass Number

Abstract

Quantum-mechanical optical model methods for calculating cross sections for the fragmentation of galactic cosmic ray nuclei by hydrogen targets are presented. The fragmentation cross sections are calculated with an abrasion-ablation collision formalism. Elemental and isotopic cross sections are estimated and compared with measured values for neon, sulfur, and calcium ions at incident energies between 400A MeV and 910A MeV. Good agreement between theory and experiment is obtained. Introduction The fragmentation of galactic cosmic ray (GCR) nuclei in hydrogen targets is an important physical process in several areas of space radiation physics research. In astrophysics, it is crucial to understanding cosmic ray propagation and source abundances (ref. 1) because interstellar hydrogen is the major type of material encountered by GCR nuclei traveling through the universe. In studies of spacecraft shielding for interplanetary missions (ref. 2), hydrogen has been found to be the most effective..