Coincidence tests of a Compton telescope based on continuous LaBr3 crystals and SiPMs for dose monitoring in hadron therapy

In hadron therapy, a proton or carbon ion beam interacts with the tissue and prompt gamma rays are emitted from the excited nuclei that can be employed for dose monitoring. A Compton telescope makes it possible to locate the origin of these photons, allowing an indirect estimation of the delivered dose. The telescope prototype being developed at IFIC-Valencia within the ENVISION project will consist of three detector layers. Each layer will be composed of a continuous LaBr₃ crystal coupled to four Silicon Photomultiplier (SiPM) arrays. Coincidence tests have been carried out with a first layer of a 16 mm × 18 mm × 5 mm LaBr₃ crystal coupled to a 16 mm × 18 mm SiPM array and a second layer of a 12 mm × 12 mm × 5 mm LYSO crystal coupled to another 16 mm × 18 mm SiPM array. The test system is read out by two SPIROC1 boards working in time coincidence. First data have been taken and the results demonstrate the feasibility of operating the system.