Tritium watch, H3 Watches, gas light watches, GTLS Watches Working Principle

What is GTLS?

GTLS stands for Gaseous Tritium Light Sources, these are tiny glass vials with a thin coating of Phosphorescent substance on the inside wall. Filled with Tritium gas and then sealed tight with a laser beam. Tritium (H3) is a radioactive isotope of Hydrogen, It has a half life of 12.3 years. During the decay of Tritium, a low energy electron is emitted. This process so called beta Radiation. During this process of decay the tritium molecule becomes a stable Helium molecules. The emitted electron hits the thin coating of Phosphorescent substance and is converted into visible cold light. The colour of the light depends o the types of the phosphorescent substance being used.

The disintegration process of the tritium isotope (represented in red) into helium (yellow) produces electrons (blue). The energy of thee electrons, should it reach the thin layer if the luminous matters (green) gets converted into a visible, cold light.

GTLS watches bear others names: Tritium watch, H3 Watches, gas light watches…



How long Can a GTLS glow?

The GTLS in a watch can glow over 25 years. It grows by itself without having to be charged with electricity or sunlight. The reduction of brightness is continuous. Generally, I is around 10-15% per year.

Is a Watch using GTLS safe?!

Yes, it is safe, During the decay process of tritium, a low energy electron is emitted. It contains only a maximum energy of 18KeV. Its is a very low energy level. It Can be easily blocked by a piece of thin paper. Therefore, it does not have the energy to penetrate human tissue. Beside, the tritium is trapped inside a glass vial which is further protected by the crystal of the watch,. If we break all the lights in a watch (typically 14 to 15 pcs of gas tubes with a total radiation content of less than 25mCi) and inhale all the tritium gas inside., the harm to our body is like consuming a banana. A banana will take in potassium 40 (K-40) while growing, K-40 is also radioactive.

Reference: Bonding Co Ltd, legally Licensed Assembly of GTLS in Hong Kong.

HK Snob