Absolute calibration of X-ray semiconductor detectors against synchrotron radiation of the VEPP-3 storage ring

The results are presented of absolute spectral responsivity measurements fo r SPPD11 and SPPD11-04 pulse-type silicon semiconductor detectors (develope d by the Research Institute of Pulse Technique, Moscow), carried out over t he X-ray energy range from 1.5 keV to 20 keV with a relative uncertainty (k = 1) of typically 5 x 10(-2). In our measurements, the detector is positio ned in a calculable synchrotron radiation flux behind filters of well-known transmittance. The spectral responsivity of the detector is restored on th e basis of measurement data using a set of integral equations. Two procedur es have been developed to improve the calibration accuracy: one for the exp erimental determination of the X-ray transmittance near the K absorption ed ge of the filters used, with a relative uncertainty not exceeding 2 x 10(-2 ); and another for the estimation of the angular spread of the electrons.