Nuclear fragmentation cross sections and cosmic-ray source abundances

Current experimental data provides constraints upon the nuclear excitation functions for 160P + p → 14N, 15N, 13C and their progenitors. These cross sections, combined with the elemental and isotopic ratios measured at Earth, are used in a complete model of cosmic ray propagation to study the source composition. The 14N O ratio in the cosmic ray source matter is appreciably less than its value in the solar system, while the source 13C C ratio is in agreement with solar system or local galactic material but not with matter near the galactic center. © 1984