Radiative neutron capture by deuterium

The ²H(n,{γ})³H reaction has been studied with polarized and unpolarized neutrons of energies ranging from 9 to 14 MeV. Angular distributions of cross section were measured at Eₙ(lab)=9.0, 10.8, and 14.0 MeV, {σ}(90^∘{}) was measured at 6.85 MeV, and an analyzing-power angular distribution was measured at 9.0 MeV. The results for {σ}(theta) agree with the existing ³H({γ},n)²H data after detailed balancing. The resulting ³He({γ},p)/³H({γ},n) ratio for 90^∘{} cross sections is 1.1±{}0.15 down to Eₓ=10.8 MeV. The T-matrix analysis of the data indicates {~}3% for the E2 contribution to the capture cross section---comparable to that found earlier for ²H(p,{γ})³He and in contrast to the predictions [σ_n(E2)/σp(E2)=1/25] of a two-body direct-capture calculation.