TY - JOUR
T1 - Development of a new pinhole camera for imaging in high dose-rate environments
AU - Sueoka, Koki
AU - Kataoka, Jun
AU - Takabe, Miho
AU - Iwamoto, Yasuhiro
AU - Arimoto, Makoto
AU - Yoneyama, Masaki
AU - Yoda, Isao
AU - Torii, Tatsuo
AU - Sato, Yuki
AU - Kaburagi, Masaaki
AU - Terasaka, Yuta
N1 - Funding Information:
This work was supported by JSPS KAKENHI Grant Number JP15H05720
Publisher Copyright:
© 2017 Elsevier B.V.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2018/12/21
Y1 - 2018/12/21
N2 - After Fukushima's nuclear disaster in Japan, the decontamination operation is successfully ongoing, and restrictions from some areas were lifted in April 2017. However, the radiation dose rate in the Fukushima Daiichi Plant is still so high (e.g., from a few mSv/h up to 530 Sv/h) that the decommissioning operation of the reactor remains a serious problem. Visualization of radioactive materials would help address this, but no gamma camera is available at this moment that can take images in such a high dose-rate environment. In this study, we developed a new gamma camera featuring a wide dynamic range from sub-mSv/h to more than 680 Sv/h, for a quick and accurate visualization of radioactive materials. The camera consists of a pinhole collimator, a Gd2O2S:Tb (GOS) scintillator sheet, and an electron multiplying charge-coupled device (EM-CCD). Gamma rays passing through the pinhole collimator hit the GOS scintillator sheet, which emits scintillation light. The luminescence of the GOS scintillator sheet is monitored in real-time with an EM-CCD with an internal multiplication gain of up to 20. By changing the exposure time, electron multiplication gain, and aperture of the EM-CCD, a wider dynamic range covering five orders of magnitude in the radiation dose can be monitored for the first time. We show that the positions of a 137Cs source (662 keV) and 60Co source (1173, 1333 keV) are identified correctly with a typical angular resolution of 10° full width at half maximum (FWHM). We also confirmed a linear relation between the absorbed dose and the luminescence of the GOS scintillator sheet. Finally, we propose a new concept of ”color imaging”, by using multi-layered scintillators consisting of a Ga3Al2Gd3O12 (GAGG) scintillator, fluorescent glass, and a plastic scintillator.
AB - After Fukushima's nuclear disaster in Japan, the decontamination operation is successfully ongoing, and restrictions from some areas were lifted in April 2017. However, the radiation dose rate in the Fukushima Daiichi Plant is still so high (e.g., from a few mSv/h up to 530 Sv/h) that the decommissioning operation of the reactor remains a serious problem. Visualization of radioactive materials would help address this, but no gamma camera is available at this moment that can take images in such a high dose-rate environment. In this study, we developed a new gamma camera featuring a wide dynamic range from sub-mSv/h to more than 680 Sv/h, for a quick and accurate visualization of radioactive materials. The camera consists of a pinhole collimator, a Gd2O2S:Tb (GOS) scintillator sheet, and an electron multiplying charge-coupled device (EM-CCD). Gamma rays passing through the pinhole collimator hit the GOS scintillator sheet, which emits scintillation light. The luminescence of the GOS scintillator sheet is monitored in real-time with an EM-CCD with an internal multiplication gain of up to 20. By changing the exposure time, electron multiplication gain, and aperture of the EM-CCD, a wider dynamic range covering five orders of magnitude in the radiation dose can be monitored for the first time. We show that the positions of a 137Cs source (662 keV) and 60Co source (1173, 1333 keV) are identified correctly with a typical angular resolution of 10° full width at half maximum (FWHM). We also confirmed a linear relation between the absorbed dose and the luminescence of the GOS scintillator sheet. Finally, we propose a new concept of ”color imaging”, by using multi-layered scintillators consisting of a Ga3Al2Gd3O12 (GAGG) scintillator, fluorescent glass, and a plastic scintillator.
KW - Fukushima
KW - High dose-rate
KW - Pinhole camera
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U2 - 10.1016/j.nima.2017.10.082
DO - 10.1016/j.nima.2017.10.082
M3 - Article
AN - SCOPUS:85036497312
VL - 912
SP - 115
EP - 118
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
SN - 0168-9002
ER -