Performance of the latest MPPCs with reduced dark counts and improved photon detection efficiency

We have tested the performance of two types of the latest Multi-Pixel Photon Counters (MPPCs; measuring 3×3mm2 in size) developed by Hamamatsu Photonics K.K. The new S12572-050C is a successor to the S10362-33-050C (i.e., conventional 3×3-mm2 pixel MPPC of 50μm pitch), comprises 3600 Geiger mode avalanche photodiodes (APDs), and also features high gain (up to 1.25×106), a low dark count (up to 106cps), and improved photon detection efficiency (PDE) by up to 30%. The S12572-015C is a new type of fine-pitch (15μm) MPPC featuring a wide dynamic range and fast timing response. This paper first presents the detailed performance of these latest MPPCs as photon counting devices. It then describes our fabrication of a prototype detector consisting of a MPPC optically coupled with a Ce:GAGG scintillator. We obtained average FWHM energy resolutions of 7.3% (15μm) and 6.7% (new-50μm), as compared to 6.9% (old-50μm) for 662-keV gamma rays from the 137Cs source, as measured at 20°C. Moreover, the number of fired pixels for 662-keV gamma rays increased by 30% for the new-50μm (as compared to the old-50μm). We confirmed that the low energy threshold improved from 10keV to 4keV, when using the latest MPPC device (new-50μm). We also confirmed that the timing resolution of the new MPPC is 50ps or even better, as compared to 89ps of the old MPPC. The results thus confirm that these new types of MPPCs are promising for various applications as scintillation detectors. •We tested the performance of the latest MPPC.•We confirmed that the new MPPC is superior to the old MPPC.•We plan to apply the new MPPC for a next-generation PET and a handy Compton camera.