Abstract
We investigated the effects on cosmic rays from spallation reactions between cosmic rays and interstellar helium. The spallation cross sections were measured by exposing thin-sandwich targets to the 920-MeV (230-MeV/) external -particle beam of the 184-in. cyclotron at Lawrence Berkeley Laboratory. Cross sections were measured for the production: from of (12.5±0.5 mb); from of (46.4±2.7 mb), (6.75±0.5 mb), (18.5±0.9 mb), and (18.5±1.3 mb); from of (20.0±1.2 mb); and from of (12.6±0.8 mb). We constructed spallation cross-section ratios for the ratio of -particle-induced to proton-induced reactions (). We parametrized this ratio by the nucleon difference () between the target initial and final states and we fitted this ratio [] to a linear function in . We used this function [] to obtain all of the -particle-spallation cross sections from the corresponding proton-spallation cross sections for targets and products in the elemental range , and we applied these cross sections to a cosmic-ray transport calculation wherein we investigated the sensitivity of the cosmic-ray ratio [=(Li + Be + B) / (C + N + O)] and of the abundances of the and elements to the helium fraction of the interstellar gas.
[NUCLEAR REACTIONS , , , ; , MeV; measured ; NaI detector. Examined effect interstellar He on cosmic rays.]
- Received 29 November 1973
DOI:https://doi.org/10.1103/PhysRevC.9.1718
©1974 American Physical Society