Triton Memory Time in Solid DT and its Nuclear Polarization
Fusion Science and Technology / Volume 14 / Number 2P2A / September 1988 / Pages 855-863
Tritium Properties and Interactions with Material / Proceedings of the Third Topical Meeting on Tritium Technology in Fission, Fusion and Isotopic Applications (Toronto, Ontario, Canada, May 1-6, 1988) / dx.doi.org/10.13182/FST88-A25242
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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.
