Xenon arc lamp
A xenon arc lamp is a highly specialized type of gas discharge lamp, an electric light that produces light by passing electricity through ionized xenon gas at high pressure. It produces a bright white light that closely mimics natural sunlight, with applications in movie projectors in theaters, in searchlights, and for specialized uses in industry and research to simulate sunlight, often for product testing.
Xenon headlamps in automobiles are actually metal-halide lamps, where a xenon arc is only used during start-up to correct the color temperature.
Types[edit]
Xenon arc lamps can be roughly divided into three categories: continuous-output xenon short-arc lamps, continuous-output xenon long-arc lamps, and xenon flash lamps (which are usually considered separately).
Each consists of a fused quartz or other heat resistant glass arc tube, with a tungsten metal electrode at each end. The glass tube is first evacuated and then re-filled with xenon gas. For xenon flashtubes, a third "trigger" electrode usually surrounds the exterior of the arc tube. The lifetime of a xenon arc lamp varies according to its design and power consumption, with a major manufacturer quoting average lifetimes ranging from
Xenon long-arc-lamps
These are structurally similar to short-arc lamps except that the distance between the electrodes in glass tube is greatly elongated. When mounted within an elliptical reflector, these lamps are frequently used to simulate sunlight in brief flashes, often for photography. Typical uses include solar cell testing (with the use of optical filters), solar simulation for age testing of materials, rapid thermal processing, material inspection and sintering.
Though not commonly known outside of Russia and the former Soviet satellite countries, long arc xenon lamps were used for general illumination of large areas such as rail stations, sports arenas, mining operations, and nuclear power plant high bay spaces. These lamps, Лампа ксеноновая ДКСТ, literally "lamp xenon DKST" were characterized by high wattages ranging from 2kW to 100 kW. The lamps operated in a peculiar discharge regime where the plasma was thermalized, that is, the electrons were not significantly hotter than the gas itself. Under these conditions a positive current-voltage curve was demonstrated. This allowed the larger common sizes such as 5 and 10kW to operate directly from mains AC at 110 and 220 volts respectively without a ballast – only a series igniter was necessary to start the arc.
The lamps produced around 30 lumens/watt, which is about double the efficiency of the tungsten incandescent lamp, but less than more modern sources such as metal halide. They had the advantage of no mercury content, convective air cooling, no high pressure rupture risk, and nearly perfect color rendition. Due to low efficiency and competition from more common lamp types, few installations remain today, but where they do, they can be recognized by a characteristic rectangular/elliptical reflector, and crisp blue-white light from a relatively long tubular source
