YAP:Ce scintillator as an absolute ultracold neutron detector

The upcoming UCNProBe experiment at Los Alamos National Laboratory will measure the β-decay rate of free neutrons with different systematic uncertainties than previous beam-based neutron lifetime experiments. We have developed a new ^10B-coated YAP:Ce scintillator whose properties are presented. The advantage of the YAP:Ce scintillator is its high Fermi potential, which reduces the probability for upscattering of ultracold neutrons, and its short decay time, which is important at high counting rates. Birks' coefficient of YAP:Ce was measured to be (5.56^+0.05_-0.30)× 10^-4 cm/MeV and light losses due to 120 nm of ^10B-coating to be about 60 polystyrene scintillator was about 50 that are captured on the ^10B coating is (86.82 ± 2.61) with ultracold neutrons showed that YAP:Ce crystal counted 8 compared to ZnS screen. This may be due to an uneven coating of ^10B on the rough surface.