A Prompt Gamma-ray Detection Module for Imaging, Timing and Spectroscopy in Hadrontherapy Applications

We present a gamma-ray detection module consisting of a 8×8 pixelated LYSO scintillator coupled with a 64-SiPM array, four custom 16-channel SITH ASICs and a FPGA-based DAQ system providing a real-time measurement of the gamma-ray hit position, energy and time-of-arrival through 64 TDCs implemented in FPGA. The detector and readout electronics have been specifically designed and optimized for the prompt gamma (PG) imaging application used for range monitoring in hadrontherapy and thus feature a high countrate capability (up to 0.6 Mcps per channel), a large dynamic range of ~ 90 dB (for reading energies up to 8 MeV deposited in a single crystal pixel) and the possibility of scattering correction through time coincidence measurement. We report the design of the 64-channel detection module electronics, along with a preliminary experimental measurements of a first 16-channel prototype of the system in terms of energy and timing performance. The timestamp difference distribution obtained by pulsing two TDC channels shows a FWHM of 110 ps.