Used in spectroscopy when constant and intense ultraviolet light is required, the deuterium lamps are low-pressure, gas-discharge light sources. These light sources utilize a heated tungsten filament that manufactures an arc to the anode in order to excite molecular deuterium for visible and infrared light production. Whether using the deuterium lamps for UV spectroscopy or as astandard for UV spectral irradiance, outputs are uniform and stable.