Cryogenic detectors below 100 mK for X-ray measurements in metrology

Due to the intrinsic performances of cryogenic detectors such as energy res olution, LPRI has decided to use these devices to improve the quality of th e radioactive measurements usually obtained with classical semiconductor de tectors. A bolometer with a 10 mu g tin absorber has been developed at IAS (Institut d'Astrophysique Spatiale) and has been tested in the cryogenic in stallation of LPRI; an energy resolution (full width half maximum, FWHM) of 39 eV has been obtained on the K alpha line of Mn. Besides these good spec trometry results, an absolute activity measurement using bolometers is prop osed by adapting an absorber geometry for 4 pi counting. (C) 2000 Elsevier Science Ltd. All rights reserved.