Design and development of trigger-driven readout with X-ray SOI pixel sensor

We have been developing a monolithic active pixel sensor with the Silicon-On-Insulator (SOI) CMOS technology, called SOIPIX, for future X-ray astronomical satellite missions. The goal of SOIPIX is to replace the X-ray CCD, which is the standard detector in the field, by offering superior time resolution (~10 μs) and wider bandpass (0.5 keV - 40 keV) in addition to having comparable performances in imaging spectroscopy. In the previous work, we built a SOIPIX prototype, XRPIX1, and confirmed the basic X-ray performance of imaging spectroscopy in a mode reading out the whole area (all pixels). The next step is to realize a high-speed and intelligent readout for X-ray detection. XRPIX1 contains trigger circuit in each pixel to detect an X-ray photon and is capable of direct access to the local pixels to read out the signal amplitude. We report on the design and development of a trigger-driven readout system with XRPIX1. We present the first resolved X-ray spectra of Cu+Mo and Am-241 obtained in the trigger-driven mode.