Improvement of energy thresholds for scintillation detectors using a monolithic 2 × 2 multi-pixel photon counter array with a coincidence technique

Takamasa Miura, Takeshi Nakamori, Jun Kataoka, Takuya Kato, Kenichi Sato, Yoshitaka Ishikawa, Kazuhisa Yamamura, Nobuyuki Kawabata

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    Abstract

    The performance of a large-area, monolithic Hamamatsu multi-pixel photon counter (MPPC) was tested consisting of a 2 × 2 array of 3 × 3 mm2 pixels. MPPC is a novel type of semiconductor photodetector comprising multiple avalanche photodiode (APD) pixels operated in Geiger mode. Despite its great advantage of signal multiplication comparable to that achieved with the photomultiplier tube (PMT), the detection of weak scintillation light signals is quite difficult due to the severe contamination of dark counts, which typically amounts to ≳1 Mcps/3 × 3 mm2 at room temperature. In this study, a coincidence technique was applied for scintillation detectors to improve the detection efficiency for low energy gamma-rays. The detector consisted of a 10 × 10 × 10 mm3 crystals of GSO, BGO, and Pr:LuAG optically coupled with the 2×2 MPPC-array. With this technique, we demonstrated that the contamination of dark counts was reduced with a rejection efficiency of more than 99.8%. As a result, 22.2keV gamma-rays were successfully detected with a GSO scintillator as measured at +20 °C.

    Original languageEnglish
    Article number094203
    JournalJournal of the Physical Society of Japan
    Volume80
    Issue number9
    DOIs
    Publication statusPublished - 2011 Sep

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    Keywords

    • Coincidence
    • Energy threshold
    • Gamma-rays
    • MPPC
    • Scintillation detector

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

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