Comparison between YAP : Ce and CsI(Tl) multipillar matrices

The characteristics of segmented CsI(Tl) and YAP : Ce scintillators coupled to a position-sensitive photomultiplier tube (PSPMT Hamamatsu R2486) have been measured and compared to evaluate the potential use of such scintillators as precise X- and γ-ray imagers. For such configurations, we obtained good spatial resolution and linearity over their entire 40×40 mm2 Fields of View (FOVs). The scintillating matrices consist of orthogonal arrays of crystal pillars with 0.6×0.6 mm2 cross sections and thicknesses of 3 and 10 mm. The 3 mm thick CsI(Tl) matrix shows a light yield of 44% compared to NaI(Tl), an energy resolution of 22% FWHM at 122 keV, a single pillar spatial response of 0.5 mm FWHM, and a spatial resolution of 0.83 mm.