Galactic Deuterium and its Energy Spectrum above 20 MeV per Nucleon

Abstract

The fluxes and energy spectra of deuterium, protons, and helium were measured on the IMP-III satellite at a time near minimum solar activity. The deuterium differential energy spectrum in the range 17-63 MeV/nucleon is $\propto E^{+2\mathrm{}}$ and, at 60 MeV/nucleon, the relative abundance ratios are ${\mathrm{H}}^2$/${\mathrm{He}}^4$=0.15 and ${\mathrm{H}}^2$/${\mathrm{H}}^1$=0.05. If present values of experimental cross sections for the production of ${\mathrm{H}}^2$ from nucleon interactions with ${\mathrm{He}}^4$ are used, the observed deuterium abundance may be accounted for by the traversal of ${\mathrm{He}}^4$ through 4 to 6 g/${\mathrm{cm}}^2$ of matter in cosmic-ray sources and the interstellar medium.