Luminous paint paint was used to illuminate Apollo Lunar Module electrical switch tips and painted on control panels of the Lunar Roving Vehicle. The latest generation of the radioluminescent materials is based on tritium, a radioactive isotope of hydrogen with half-life of 12.32 years that emits very low-energy beta radiation. The devices are similar to a fluorescent tube in construction, as they consist of a hermetically sealed (usually borosilicate-glass) tube, coated inside with a phosphor, and filled with tritium. They are known under many names – e.g. gaseous tritium light source (GTLS), traser, betalight. Tritium light sources are most often seen as
Radioactive tracer atomic nucleus of an isotope is unstable, compounds containing this isotope are radioactive. Tritium is an example of a radioactive isotope. The principle behind the use of radioactive tracers is that an atom in a chemical compound is replaced by another atom, of the same chemical element. The substituting atom, however, is a radioactive isotope. This process is often called radioactive labeling. The power of the technique is due to the fact that radioactive decay is much more energetic than chemical reactions. Therefore, the radioactive isotope can be present in low concentration and its presence detected by sensitive radiation detectors