Comparative study of PP0275C hybrid photodetector and XP2020Q photomultiplier in scintillation detection

Properties of a hybrid photodetector (HPD), type PP0275C, produced by Delft Electronic Products B.V., for scintillation detection and spectrometry were studied and compared to a standard XP2020Q photomultiplier. The study was performed for several scintillators, as NaI(Tl), CsI(Tl), and LSO of different dimensions. The excellent capability of the HPD to resolve single photoelectron events was fully confirmed. However, the study of the HPD with the scintillators showed a dramatically reduced number of photoelectrons and a further deterioration of energy resolution, depending on the size (diameter or length) of the crystals. For a 10 mm diameter NaI(Tl) the number of photoelectrons of 5000/spl plusmn/250 phe/MeV was measured, which corresponds to about 56% of that observed with the XP2020Q with comparable quantum efficiency. Energy a /sup 137/Cs resolution of 9.2% for 662 keV /spl gamma/-rays from, source measured with the HPD light readout showed a serious degradation, larger than that arising from the statistics of photoelectrons. In conclusion, the study showed that this HPD is optimized for single photon detection and its application to scintillation detection is very limited.