Triton (nuclear physics)

Article By:

Hamilton, Joseph H. Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee.

Last reviewed:January 2021

DOI:https://doi.org/10.1036/1097-8542.711000

The nucleus of ³₁H₂ (tritium); it is a radioactive nuclide with one proton and two neutrons belonging to hydrogen. The triton is produced in nuclear reactors by neutron absorption in deuterium (²₁H₁ + ¹₀ n₁  →  ³₁H₂ + γ), and in hydrogen fusion bombs via the reaction ¹ n +  ⁶₃Li → ³₁H₂ + ⁴₂He₂ + 4.9 MeV. It decays by β⁻ emission to ³₂He₁ with a half-life of 12.32 years. The spin of the triton is 1/2, its magnetic moment is 2.978962 nuclear magnetons, and its mass is 3.015501 atomic mass units. Much of the interest in producing ³₁H₂ arises from the fact that the fusion reaction ³₁H₂ + ²₁H₁ → ⁴₂He + n releases about 18 MeV of energy and has a large production cross section at lower temperatures. Tritons are also used as projectiles in nuclear bombardment experiments. Measurements of the beta spectrum of the triton have been used to set very low limits for the mass of the electron neutrino. See also: Neutrino; Nuclear fusion; Nuclear reaction; Radioactivity; Tritium

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