Wavelength-shifting fiber signal readout from Transparent RUbber SheeT (TRUST) type LiCaAlF₆ neutron scintillator

As an alternative to the standard ³He neutron detector, we are developing the Transparent RUbber SheeT type (TRUST) Eu doped LiCaAlF₆ (Eu:LiCAF) scintillator. This type of neutron scintillator can easily be fabricated as a large area sheet. In order to take advantage of a large area detector, we try to readout scintillation photons using a wavelength-shifting fiber (WLSF) from a TRUST Eu:LiCAF scintillator. The TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm³ was mounted on the WLSF plate and the end of the WLSFs was connected with a PMT. In order to reject high pulse height events induced in the WLSFs, we applied the pulse shape discrimination technique. The gamma-ray intrinsic and neutron absolute detection efficiency is evaluated to be 8.8×10⁻⁷ and 9×10⁻³ cps/ng Cf (2 m) for the TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm³