Study of large area Hamamatsu avalanche photodiode in a γ-ray scintillation detector

Abstract: We have carried out study of a large area , reverse-type avalanche photodiode (APD) recently developed by Hamamatsu photonics. It has low dark current of 3nA at room temperature, and the gain stability was almost the same as prototypical APDs reported in our previous paper. We studied the performance as a -ray detector with four scintillators, CsI(Tl), BGO, GSO(Ce), and YAP(Ce) crystals. For example we obtained the best energy resolution of (FWHM) for 662keV -rays, as measured with a CsI(Tl) crystal. The minimum detectable energy was as low as 10keV at and 3.1keV at . Thanks to its large effective area, this APD can effectively read out photons from larger size scintillators. When coupling to a BGO plate of 3mm thickness, an FWHM energy resolution of was obtained for 662keV -rays, with the minimum detectable energy of about 60keV at . These results suggest that our prototype APD can be a promising device for various applications replacing traditional PMTs such as use in space for Japan''s future X-ray astronomy mission NeXT. [Copyright &y& Elsevier]