Tritium Production by High-Energy Protons

The cross sections for tritium production in various substances by 450-Mev and 2.05-Bev protons have been measured. The nitrogen and oxygen cross sections—25±4 mb and 30±4 mb, respectively, at 2.05 Bev—lead to a world-wide average tritium production rate by cosmic rays of ${0.14}_{-0.03\mathrm{}}^{+0.10\mathrm{}}$ tritons/${\mathrm{cm}}^2$ sec, in good agreement with the observed value. The iron cross section—53±8 mb at 2.05 Bev—suggests a rate of production of 8.8×${10}^{-4\mathrm{}}$ triton/g sec near the surface of a large meteorite in outer space. For the small Mt. Ayliff iron meteorite an age of 1.4×${10}^9$ years was calculated from the observed ${\mathrm{He}}^3$ content. Finally, the results for tritium production have been compared to those for other light particles.