Tritium Gas-filled Light Sources (GTLS)
are sealed borosilicate glass capsules coated internally
with a phosphor and filled with tritium gas.
Tritium is an isotope of hydrogen which emits low energy beta-radiation, which in turn excites the phosphor causing it to emit visible light.
The wavelength and colour of the light depends upon the make-up of the phosphor.
GTLS are inherently safe for use in hazardous environments.
Colour and brightness
GTLS can be supplied in a range of colours. Since the human eye is more sensitive to green and yellow, these colours are the most widely used.
The brightness of GTLS varies with the tritium content. They are filled at pressures of up to 2 bar to achieve maximum brightness.
The unit of light output is the micro-lambert (ÂµL), typical values falling within the range of 10 to 2000 ÂµL.
Reliability and maintenance
GTLS offer long term reliability and require no maintenance. Once installed, a useful life of at least 20 years can be expected. However, there will be a gradual drop in brightness due to radioactive decay (TÂ½ ca. 6 years).
Shapes and sizes
GTLS are produced in a wide range of shapes and sizes:
tubes, curves, circles, rectangles, squares, axial discs, spheres etc. in a wide range of dimensions.