Scintillation light yield of Tb:Sr2Gd8(SiO4)6O2

Abstract

We have constructed the scintillation light yield evaluation system for the scintillator with millisecond decay time, which is based on the digital signal processing and the analog integration circuit with the decay time of 0.1 ms. The digital pulse shape discrimination technique is introduced to check and/or remove the influence of the pile-up events. As the first trial of the absolute scintillation light yield evaluation for scintillators with millisecond decay time, we attempt to acquire the scintillation light yield spectrum of the Tb:Sr2Gd8(SiO4)6O2 (Tb:SrGS). The pulse area spectrum obtained from the Tb:SrGS scintillator shows a clear peak corresponding to the full-energy absorption events of 662 keV gamma-rays from a Cs-137 source. The peak channels in the pulse area spectra are almost the same both for the Tb:SrGS and bismuthgermanate (BGO) scintillator. Considering the difference in the wavelength matching between scintillators and the photomultiplier tube, the Tb:SrGS scintillator has a 2.8 times higher scintillation light yield compared with the BGO. We finally conclude that the scintillator light yield of the Tb:SrGS is evaluated to be 23 000 photons MeV−1.