Development of an indirect conversion X-ray photon counting module toward achieving maximum count rate of 100 Mcps/mm2

X-ray photon counting (XPC), a low-noise method of detecting transmitted X-rays and binning them into multiple energy regions, is highly promising in fields such as medical imaging, in-line inspection, infrastructure inspection, and cargo inspection. The indirect conversion type XPC detector that combines a scintillator and a Multi-Pixel Photon Counter (MPPC) has excellent characteristics such as high inter-channel separation characteristics, high stopping power, and low drive voltage, which are important in these applications. However, the conventional indirect conversion sensor has the serious problem of low maximum count rate.Recently, we reported a new XPC module with 20 Mcps/mm
²
maximum count rate and which incorporates a high-speed scintillator. In this paper, the development of the XPC module toward achieving 100 Mcps/mm
²
, such as the development of a high-speed and low-power-consumption MPPC by enhancing the MPPC’s parasitic capacitance, is reported. This detector is expected to be useful, not only for simple X-ray transmission imaging, but also for density/concentration analysis and material decomposition analysis.