How does a Tritium exit sign work?
Self-luminous signs use the electrons from tritium (also called hydrogen 3 gas or H3) to provide illumination without the need for a source of electrical power. The process is very similar to that in your television set picture tube whereby an electron is used to illuminate the front screen of the tube. The electrons from tritium however have only about one quarter of the energy of the electron in a colour TV picture tube. That is why self-luminous signs are not visible in daylight while TV pictures are. Actually, the tritium electron from the tritium has such a low energy that it cannot even penetrate an ordinary sheet of paper. Because of this very low energy level, tritium is one of the safest and most benign of all radioactive materials and is therefore approved by the relevant authorities for use in self-luminous signs in commercial buildings as well as all commercial aircraft. To produce the illumination, the tritium gas is contained within a hermetically sealed glass tube. The i
