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

Research output: Contribution to journalArticle

69 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

    Fingerprint

Keywords

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

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation

Cite this