Development of Si‐APD Timing Detectors for Nuclear Resonant Scattering using High‐energy Synchrotron X‐rays

A timing detector with silicon avalanche photodiodes (Si‐APDs) has been developed for nuclear resonant scattering using synchrotron x‐rays. The detector had four pairs of a germanium plate 0.1mm thick and a Si‐APD (3 mm in dia., a depletion layer of 30‐μm thickness). Using synchrotron x‐rays of 67.4 keV, the efficiency increased to 1.5% for the incident beam, while the efficiency was 0.76 % without the germanium converters. A measurement of SR‐PAC on Ni‐61 was executed by using the detector. Some other types of timing detectors are planned for x‐rays of E>20 keV.