Detector characterization and first coincidence tests of a Compton telescope based on LaBr_3 crystals and SiPMs

摘要

A Compton telescope for dose monitoring in hadron therapy consisting of several layers of continuous LaBr_3 crystals coupled to silicon photomultiplier (SiPM) arrays is under development within the ENVISION project. In order to test the possibility of employing such detectors for the telescope, a detector head consisting of a continuous 16 mm × 18 mm × 5 mm LaBr_3 crystal coupled to a SiPM array has been assembled and characterized, employing the SPIR0C1 ASIC as readout electronics. The best energy resolution obtained at 511 keV is 6.5% FWHM and the timing resolution is 3.1 ns FWHM. A position determination method for continuous crystals is being tested, with promising results. In addition, the detector has been operated in time coincidence with a second detector layer, to determine the coincidence capabilities of the system. The first tests are satisfactory, and encourage the development of larger detectors that will compose the telescope prototype.