Nuclear magnetic resonance of anti-parallel spin neutrons (of total spin zero for the neutron-spin pair), plus a proton of spin . Therefore, the tritium total nuclear spin value is again , just like for the simpler, abundant hydrogen isotope, H nucleus (the "proton"). The NMR absorption frequency for tritium is also similar to that of H. In many other cases of "non-radioactive" nuclei, the overall spin is also non-zero. For example, the nucleus has an overall spin value . A non-zero spin formula_2 is always associated with a non-zero magnetic dipole moment, formula_3, via the relation formula_4 where "γ" is the gyromagnetic ratio.
Heavy water neutrinos, as well as a non-absorbent moderator medium to preserve free neutrons from this reaction, until they can be absorbed by an easily detected neutron-activated isotope. Heavy water is employed as part of a mixture with HO for a common and safe test of mean metabolic rate in humans and animals undergoing their normal activities. Tritium is the active substance in self-powered lighting and controlled nuclear fusion, its other uses including autoradiography and radioactive labeling. It is also used in nuclear weapon design for boosted fission weapons and initiators. Some tritium is created in heavy water moderated reactors when deuterium