Back-illuminated CCDs with high quantum efficiency for 0.35-2.5 keV X-rays
in combination with low efficiency at optical wavelengths have been develop
ed for XMM-RGS. As part of the calibration programme, a systematic study of
the CCD response in this energy range has been performed at the Synchrotro
n Radiation Source in Daresbury, UK. These measurements show the good quant
um efficiency of the CCDs. The results are consistently described by a Mont
e Carlo model. (C) 2000 Elsevier Science B.V. All rights reserved.