Measurement and simulation of proton induced activation of LaBr3:Ce

To assess the suitability of LaBr3:Ce scintillators for space mission applications, proton induced activation of LaBr3 has been investigated. The crystals were irradiated using proton beams at several different energies to mimic the spectrum of a solar flare. We have measured the activation both internally and externally by measuring the count rate in the scintillator itself and with a germanium detector. The setup allowed to identify the dominant radioactive isotopes before and after irradiation. At lower energies, we have seen that the dominant source of activation originates from proton induced activation of bromine. At energies above 2 MeV the activation is several orders of magnitude less and the spectrum shows no distinct features. In addition, we discuss results of a simulation of the activation using Monte Carlo methods in combination with state-of-the-art calculations of nuclear cross-sections. Results from the Monte Carlo simulations and the measurements agree within a factor of 2.