Response of LaBr3(Ce) scintillators to 14 MeV fusion neutrons

The response of a 3 '' x 3 '' LaBr3(Ce) scintillator to 14 MeV neutron irradiation has been measured at the Frascati Neutron Generator and simulated by means of a dedicated MCNP model. Several reactions are found to contribute to the measured response, with a key role played by neutron inelastic scattering and (n,2n) reactions on Br-79, Br-81 and La-139 isotopes. An overall 43% efficiency to 14 MeV neutron detection above an experimental threshold of 0.35 MeV is calculated and confirmed by measurements. Post irradiation activation of the crystal has been also observed and is explained in terms of nuclear decays from the short lived Br-78 and Br-80 isotopes produced in (n,2n) reactions. The results presented in this paper are of relevance for the design of gamma-ray detectors in burning plasma fusion experiments of the next generation, such as ITER, where capability to perform measurements in an intense 14 MeV neutron flux is required. (C) 2015 Elsevier B.V. All rights reserved.