The total cross section for the reaction ${\mathrm{He}}^3 (\gamma , p)\mathrm{D}$ has been measured at gamma-ray energies of 6.14, 6.97, and 7.08 MeV. The cross section was found to be 0.102, 0.298, and 0.307 mb at the three energies. The experimental cross-section values are compared with those of the inverse reaction $\mathrm{D}(p, \gamma ){\mathrm{He}}^3$, as an accurate check on the principle of detailed balance.

• Received 1 July 1963

DOI:https://doi.org/10.1103/PhysRev.132.1691