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.
Tritium can penetrate only about 6.0 mm of air, and they are incapable of passing through the dead outermost layer of human skin. The unusually low energy released in the tritium beta decay makes the decay (along with that of rhenium-187) appropriate for absolute neutrino mass measurements in the laboratory (the most recent experiment being KATRIN). The low energy of tritium's radiation makes it difficult to detect tritium-labeled compounds except by using liquid scintillation counting. Tritium is produced in nuclear reactors by neutron activation of lithium-6. This is possible with neutrons of any energy, and is an exothermic reaction yielding 4.8