Speaker
Description
Recent developments have shown the potential of a time-of-flight measurement of individual photons using fast X-ray detectors to significantly reduce the adverse effects of scattered photons both in X-ray radiography and computed tomography (CT) without using anti-scatter grids. However, the improvements observed in simulations have yet to be confirmed experimentally using a system realistic for clinical use. Producing a first CT image with real-time discrimination of scattered photons requires an ultrafast single X-ray counting system and an ultrashort pulsed X-ray source. This contribution focuses on the design and preliminary characterization of a 16-channel scintillator-based scanner. The detector is composed of 16 4x4x2.5 mm3 LYSO scintillators coupled with 16 4x4 mm2 SiPMs from Broadcom (AFBR-S4N44C013). A Nino pre-amplifier and two time-to-digital converters designed in-house read the SiPMs’ output to provide time and energy measurements using time-over-threshold. GATE simulations have shown that if a 200 ps time resolution is obtained, this system will be able to remove half of the scattered photon, resulting in a 20% increase in CNR. This system will be used to improve our understanding of time-of-flight scatter rejection and evaluate scintillators for fast X-ray measurements.
