Response function and linearity for high energy γ-rays in large volume LaBr3:Ce detectors

The response function to high energy γ-rays of two large volume LaBr3:Ce crystals (3.5”x8”) and the linearity of the coupled PMT's were investigated at the NewSUBARU facility, where γ-rays in the energy range 6–38 MeV were produced and sent into the detectors. Monte Carlo simulations were performed to reproduce the experimental spectra. The photopeak and interaction efficiencies were also evaluated both in case of a collimated beam and an isotropic source.