Light outputs of yttrium doped BaF$_2$ crystals irradiated with neutrons

TL;DR

This study investigates how neutron irradiation affects the light output and decay kinetics of pure and yttrium-doped BaF$_2$ crystals, revealing that doping increases radiation-induced light output loss and that the fast component is slightly more affected.

Contribution

It provides new data on the radiation hardness of yttrium-doped BaF$_2$ crystals, highlighting the impact of doping on light output loss after neutron irradiation.

Findings

Pure BaF$_2$ loses about 7 ext{%} light output after irradiation.

Yttrium doping increases light output loss to roughly 14 ext{%} after irradiation.

Fast component's light output decreases 2-3 ext{%} more than the slow component post-irradiation.

Abstract

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