text: Tritium is a low-energy beta emitter commonly used as a radiotracer in research and in traser self-powered lightings. The half-life of tritium is 12.3 years. The electrons from beta emission from tritium are so low in energy (average decay energy 5.7 keV)  that a Geiger counter cannot be used to detect them. An advantage of the low energy of the decay is that it is easy to shield, since the low energy electrons penetrate only to shallow depths, reducing the safety issues in deal with the isotope.
  Tritium can also be found in metal work in the form of a tritiated rust, this can be treated by heating the steel in a furnace to drive off the tritium-containing water.
  Tritium can be made by the neutron irradiation of lithium.