Deuterium Lamp
Deuterium lamps produce wide spectrum Ultra-Violet (UV) emissions and only a small amount of visible light. The outer lamp envelope is made from quartz to transmit the short-wave UV light. What makes Deuterium lamps so special, as a UV source, is its continuous spectrum in the range from 180nm - 300 nm.
Note: Short-wave Ultra Violet light is very damaging to the skin and eyes. Ozone generation is another potential hazard. This can be produced by the action of short-wave UV on oxygen in the air.
Unlike most types of discharge lamp these run on DC supply and have a pre-heated cathode. This takes the form of a filament which is initially heated by a low voltage source. The pictures on the right shows the lamp with the heater running, prior to ignition, then at ignition. The basic circuit is shown top right.
With the heater on, and the lamp voltage applied, the lamp will not start. A third supply is required to strike the arc and establish ionisation. The right most lamp is shown with the arc struck. The heater supply can be reduced or removed at this point as heating is maintained by ion bombardment, providing the arc current is high enough.
The start or strike voltage is around 400V while the running voltage is under 100V. The lamp can have a designed arc current of 300mA.
A commercial electronic driver for this type of lamp is shown below on the left.
