Ultraviolet calibration of detectors with respect to a cryogenic radiometer

A facility has been designed to perform a variety of detector characterizat ions in the air-ultraviolet in the spectral range 230 nm to 400 nm. The fac ility allows the measurement of spatial uniformity, linearity and the spect ral responsivity of different detectors, irradiated by a He-Cd laser or by a monochromator and Xe discharge lamp. With this technique, a set of Si pho todiodes, Si detectors in trap configuration, and ultraviolet (UV) radiomet ers built with SiC detectors in an integrating sphere, have been calibrated and their absolute responsivity at the He-Cd laser UV line has been determ ined with respect to an absolute cryogenic radiometer.