Light outputs of yttrium doped BaF_2 crystals irradiated with neutrons

The fast luminescence component of barium fluoride (BaF$_2$) crystals with a subnanosecond decay time can find wide application in particle physics and nuclear physics. However, the slow 630~ns could cause pile-up signals at high rate environment. Doping BaF$_2$ rare earth elements suppresses emission component, but same radiation hardness deteriorates. This work presents results studying crystal samples, both pure those doped yttrium proportion 1at.\%Y, 3at.\%Y 5at.\%Y, irradiated neutron fluence about 2.3$\times$10$^{14}$~n/cm$^2$. Their light output kinetics were measured before after irradiation. It is found that loss irradiation 7\%, samples two times higher. measurement demonstrate each sample has relative 2-3\% larger than one.