Tritium illumination

Tritium gas light sources ( GTLS also, from the English " Gaseous tritium light source" ), known under the trade names trigalight and Beta Light, are light sources that light visible for several decades without any external power supply. A tritium gas light source consists of a glass tube of borosilicate glass, which is coated on the inside with a bulb ( " phosphorus " ) and filled with tritium. Tritium gas light sources were invented in the 1960s; they shine much stronger than the previously known tritium luminous colors.

Use

Tritium gas light sources are used as emergency lighting for signs and for dials and hands of watches. Other uses include key chains and similar "Glow -in- the-dark " products. Since they still have in addition to their life the advantage of being independent of external energy supply, they are also used by the military, but also by some hunters to signpost. They can also fishing replace the glow stick.

Operation

Tritium gas light source consists of a portion of a generally tubular borosilicate glass, which is coated on the inside with a layer of a fluorescent substance (fluorescent). In the tube, the tritium emits relatively constant from beta radiation. Under the action of the beta radiation of fluorescent photons emitted in a typical for the fluorescent light color, which makes the weak and only after years of decreasing strength lights. Since the tritium emits and thereby transformed into the stable helium isotope 3He due to the beta decay beta radiation, the intensity decreases with the half-life of tritium (about 12.3 years ), as well as the amount of tritium decreases.

In the manufacture of a glass capillary is filled with radioactive tritium (a natural isotope of hydrogen ). Thereafter, using a laser small sections (a few millimeters to 10 centimeters) sealed and cut the capillary.

Theoretically, it is possible to fill any beta emitters in the tube in order to achieve this function. However, tritium is particularly well suited because it is itself and its decay product non-toxic and the energy of the beta radiation is very low (maximum 18.6 keV).

Hazards

Intact tritium gas light sources shield the beta radiation of radioactive tritium from complete. Due to the deceleration of the electrons, however, bremsstrahlung in X-rays, which penetrate outwards it. Gas light sources with high tritium content can increase the radiation exposure.

If the glass tube is damaged and leaking tritium, there is little danger to humans and the environment, as the body by inhalation, it receives and passes it emits beta radiation. The particular danger of tritium is its biological activity, that is, it can reach as hydrogen in the natural cycle and, for example, as part of then radioactive drinking water cause damage. Because of the small amount of tritium containing tritium gas light sources and the relatively low penetration of tritium gas light sources, however, this does not constitute a great danger

Legality

Tritium gas light sources are in most of the world legally, especially for the civilian market but only with special conditions.

For the civilian sector applies in Germany:

• An activity of 1 GBq must not be exceeded.
• From an activity of 0.5 Bq / g, the manufacturer must light sources, take back.
• The production and import require approval.

The total activity of tritium gas light sources which begins to be used in watches and small keychain with a GBq ( trigalight marker) and ranges up to 17.5 GBq ( trigalight Glowring similar NITE GlowRing ). The light source of the flashlight used mainly in the military area " Beta Light Torch" has an activity of 70 GBq.

The ownership of the tritium gas light sources with a total activity of about 1 GBq is subject to approval in Germany. The possession without a permit is an offense and can be punished by a fine of up to € 50,000.