A novel gamma-ray detector with submillimeter resolutions using a monolithic MPPC array with pixelized Ce:LYSO and Ce:GGAG crystals

T. Kato, J. Kataoka, T. Nakamori, T. Miura, H. Matsuda, A. Kishimoto, K. Sato, Y. Ishikawa, K. Yamamura, S. Nakamura, N. Kawabata, H. Ikeda, S. Yamamoto, K. Kamada

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


We have developed a large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of 4×4 channels with a three-side buttable package. Each channel has a photosensitive area of 3×3 mm2 and 3600 Geiger mode avalanche photodiodes (APDs). For typical operational gain of 7.5×105 at +20 °C, gain fluctuation over the entire MPPC device is only ±5.6%, and dark count rates (as measured at the 1 p.e. level) amount to ≤400kcps per channel. We first fabricated a gamma-ray camera consisting of the MPPC array with one-to-one coupling to a Ce-doped (Lu,Y) 2(SiO4)O (Ce:LYSO) crystal array (4×4 array of 3×3×10 mm3 crystals). Energy and time resolutions of 11.5±0.5% (FWHM at 662 keV) and 493±22ps were obtained, respectively. When using the charge division resistor network, which compiles signals into four position-encoded analog outputs, the ultimate positional resolution is estimated as 0.19 mm in both X and Y directions, while energy resolution of 10.2±0.4% (FWHM) was obtained. Finally, we fabricated submillimeter Ce:LYSO and Ce-doped Gd3Ga3 Al2O12 (Ce:GGAG) scintillator matrices each consisting of 1.0×1.0, 0.7×0.7 and 0.5×0.5 mm2 pixels, to further improve the spatial resolution. In all types of Ce:LYSO and Ce:GGAG matrices, each crystal was clearly resolved in the position histograms when irradiated by a 137Cs source. The energy resolutions for 662 keV gamma-rays for each Ce:LYSO and Ce:GGAG scintillator matrix were ≤14.3%. These results suggest excellent potential for its use as a high spatial medical imaging device, particularly in positron emission tomography (PET).

Original languageEnglish
Pages (from-to)235-241
Number of pages7
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Publication statusPublished - 2013 Jan 21
Externally publishedYes


  • Gamma-rays
  • Multi-pixel photon counter
  • Positron emission tomography

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


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