First spectral measurement of deuterium-tritium fusion γ rays in inertial fusion experiments

The R-matrix analysis of $A=5$ nuclear systems has been partially validated by applying the technique to the ⁵Li system and comparing the predicted γ-ray spectrum with historical data. R-matrix analysis of the similar ⁵He system was then used to predict the γ-ray spectral shape for the deuterium-tritium (DT) reaction. The resulting spectra have been used in the analysis of DT implosions on the Omega laser where the γ-ray interaction rate was measured by a gas Cherenkov detector. Comparison of predictions to experiment confirmed the presence of both 16.75 and ≈13 MeV γ-ray contributions; analysis, using R-matrix spectra, yielded a ratio of γ-ray emission from a transition to the intermediate excited state to that from a transition to the ground state of (2.1±0.4):1, substantiating the first spectral measurement of the DT fusion γ ray in an inertial fusion environment.