Triton Memory Time in Solid DT and its Nuclear Polarization

The expected value of nuclear spin polarization to inertial confinement fusion is recapitulated. A comparison of brute force polarization versus dynamic nuclear polarization, as applied to solid deuterium-tritium, is given, and the need for a long triton polarization memory time (longitudinal nuclear relaxation time) is shown. The time constant for 25 mol%T₂-50 DT-25 D₂ (D-T) is a short 0.3 s at 5 K and waiting in the presence of tritium radioactivity lowers it to 0.1 s. Enriched 90 to 96% molecular DT has been synthesized and held 3 to 4 hours at 10 K, which lowers the overall J=1 T₂ concentration to about 0.1%. The resulting memory time can be raised in this way to 0.7 to 0.8 s. These samples were then melted and nHp added, which increased the memory times to 6 to 8 s - an increase of twenty-fold over regular D-T at 5 to 6 K. The theory shows that the species shortening the triton memory time is the J=1 T₂, which can be reduced in our samples only by radioactive self-catalysis. Cryogenic distillation is considered as a possible means of removing the J=1 T₂ from molecular DT.