We developed a fast X-ray detector system for nuclear resonant scattering (NRS) experiments. Our system employs silicon avalanche photo-diode (Si-APD) as a fast X-ray sensor. The system is able to acquire both timing and energy of a single X-ray photon simultaneously in a high rate condition, 106 counts per second for one Si-APD. The performance of the system was investigated in SPring-8, a synchrotron radiation facility in Japan. Good time resolution of \SI{120}{ps} (FWHM) was achieved with a slight tail distribution in the time spectrum by a level of 10−9 at 1 ns apart from the peak. Using this system, we successfully observed the NRS from the 26.27-keV level of mercury-201, which has a half-life of 630±50 ps. We also demonstrated the reduction of background events caused by radioactive decays in a radioactive sample by discriminating photon energy.
@article{arxiv.1702.04651,
title = {Fast X-ray detector system with simultaneous measurement of timing and energy for a single photon},
author = {T. Masuda and S. Okubo and H. Hara and T. Hiraki and S. Kitao and Y. Miyamoto and K. Okai and R. Ozaki and N. Sasao and M. Seto and S. Uetake and A. Yamaguchi and Y. Yoda and A. Yoshimi and K. Yoshimura},
journal= {arXiv preprint arXiv:1702.04651},
year = {2017}
}