STABILITY UNDER VACUUM OF SILICON TRAP DETECTORS AND THEIR USE AS TRANSFER INSTRUMENTS IN CRYOGENIC RADIOMETRY

The stability of the responsivity of trap detectors under vacuum has b een studied by means of a special chamber designed for the test of pho todetectors at low pressure. The first experiments at a wavelength of 647 nm show that the responsivity variations ape smaller than the unce rtainties of the measurements, approximately 3 parts in 10(5), when th e detector operates successively in air, under vacuum, and then again in air. Calculations based on experiments with single windowless photo diodes indicate that the change in trap responsivity that is due to va cuum effects should be smaller than 1 part in 10(5), at least in the v isible part of the wavelength range. This stability makes trap detecto rs suitable for cryogenic radiometry when one uses transfer detectors under vacuum. (C) 1996 Optical Society of America