Vacuum ultraviolet radiance transfer standard based on an argon mini-arc with integral differential pumping unit

Abstract

An argon mini-arc is described which has been developed as a high radiance transfer standard in the vacuum ultraviolet between 92 and 200 nm. It incorporates an integral differential pumping unit to interface the high pressure arc to a vacuum spectroradiometric system. It is shown that the radiance is not only extremely stable and reproducible but also calculable in terms of previously determined spectroscopic and plasma properties. The alternative interface method being a magnesium fluoride window has been shown to be severely limited by the formation of colour centres in the window and a gradual accumulation of evaporated material on its surface.