PIN Silicon Diodes as EXAFS Signal Detectors.

The properties of PIN silicon diodes as X-ray detectors for EXAFS measurements with synchrotron radiation have been investigated. Electronic stability, linearity and noise current have been analyzed. The effects of diffraction peaks resulting from the crystalline nature of the diodes have been minimized by mounting the diodes on a simple device that continuously changes its orientation by a few degrees with respect to the X-ray beam. An accurate comparison between EXAFS signals monitored by ionization chambers and PIN photodiodes is presented. It is shown that good-quality EXAFS measurements with PIN photodiodes are possible if diffraction effects are eliminated.