<title>Instrument for measuring the light scattered by diffraction gratings</title>

Abstract

The instrument for measuring the light scattered from optical surfaces is described. The measurement is carried out using the 253 nm wavelength separated from continuous spectrum of high pressure mercury lamp by a double monochromator. Output signals are detected by a photomultiplier whose sensitivity falls rapidly above 300 urn. The sensitivity of the instrument is about 0.5/3 x 10k, where the numbers 0.5 and 3 x 10 characterize the niiniml detectable output signal and the maximal one (in reflected light).