Handy Compton camera using 3D position-sensitive scintillators coupled with large-area monolithic MPPC arrays

J. Kataoka*, A. Kishimoto, T. Nishiyama, T. Fujita, K. Takeuchi, T. Kato, T. Nakamori, S. Ohsuka, S. Nakamura, M. Hirayanagi, S. Adachi, T. Uchiyama, K. Yamamoto

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

89 Citations (Scopus)

Abstract

The release of radioactive isotopes (mainly 137Cs, 134Cs and 131I) from the crippled Fukushima Daiichi Nuclear Plant remains a serious problem in Japan. To help identify radiation hotspots and ensure effective decontamination operation, we are developing a novel Compton camera weighting only 1 kg and measuring just ∼10 cm2 in size. Despite its compactness, the camera realizes a wide 180 field of vision with a sensitivity about 50 times superior to other cameras being tested in Fukushima. We expect that a hotspot producing a 5μSv/h dose at a distance of 3 m can be imaged every 10 s, with angular resolution better than 10 (FWHM). The 3D position-sensitive scintillators and thin monolithic MPPC arrays are the key technologies developed here. By measuring the pulse-height ratio of MPPC-arrays coupled at both ends of a Ce:GAGG scintillator block, the depth of interaction (DOI) is obtained for incident gamma rays as well as the usual 2D positions, with accuracy better than 2 mm. By using two identical 10 mm cubic Ce:GAGG scintillators as a scatterer and an absorber, we confirmed that the 3D configuration works well as a high-resolution gamma camera, and also works as spectrometer achieving typical energy resolution of 9.8% (FWHM) for 662 keV gamma rays. We present the current status of the prototype camera (weighting 1.5 kg and measuring 8.5×14×16 cm3 in size) being fabricated by Hamamatsu Photonics K.K. Although the camera still operates in non-DOI mode, angular resolution as high as 14 (FWHM) was achieved with an integration time of 30 s for the assumed hotspot described above.

Original languageEnglish
Pages (from-to)403-407
Number of pages5
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume732
DOIs
Publication statusPublished - 2013 Jul 22

Keywords

  • Compton camera
  • Gamma rays
  • Multi-Pixel Photon Counter (MPPC)

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation

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