Radiological Facts

Our daily life is surrounded by radiation. Most of the sources are natural, some such as medical cancer treatment therapies, atomic fallout, or consumer products that contain very small amounts of radioactivity are man made.With regard to radioactivity it is important to know that there are different particles (rays) such as Alpha, Beta, Gamma rays and different energies of these particles (waves) when travelling. Every element (isotope) may have its own fingerprint of particle and energy.

The lowest energy is emitted by tritium at only approx. 17 keV energy. Other isotopes come up to the MeV range. The electron emitted by tritium is so low in energy that it is unable to penetrate the human skin. Pure T2 gas as contained in trigalight® has almost no interaction with the body and will be exhaled by >99.9%. Tritium however can be inhaled or ingested as HTO (tritiated water), where it causes a dose during its biological half-life time of approx. 5-7 days.

Radioactivity in food

Some of the not so well known natural radiation sources are foods. Radioactive isotopes can be found in many food stuffs especially bananas, mushrooms and mineral water. A calculated example shows that consuming 1 banana every other day causes the same dose as breaking a trigalight equiped watch (1GBq of activity) and absorbing 100% of it’s tritium content.
Smoking tobacco ( 20 cigarettes a day ) is factor 9000 higher this is due to the enrichment of potassium 40 isotope in the tobacco plant.

Dose by breaking a GTLS equipped watch (1GBq)

Theoretical Calculation

Average Natural Dose per year in Switzerland: 5’600 µSv

or 5’600 µSv devided through 365d = 15,3µSv/d
Inhalation of 25mCi of Tritium gas (1GBq) at 1,8E-15 Sv/Bq*
(100%) = expected calculated dose equal 20µSv
or 1,3 days of additional exposure to natural radiation.

Practical experience…
…shows that should the GTLS in a watch break, the amount of inhaled tritium is not more than approx. 35% of the total tritium content.
If we now take a 35% inhalation as a possible scenario, we end up with a realistic dose of 7 µSv caused by the 1 GBq tritium gas content of all lights.

This is equal to a 0.455 day (= 10.9 hours) exposure to natural radiation.

* Dose factor as per Swiss Radiation Safety Regulations 814.501, July 12th 2005, Appendix 3