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64 cm
area position-sensitive scintillation neutron detector as an alternative to helium-3 gas based detectorNakamura, Tatsuya; To, Kentaro; Honda, Katsunori; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru
Proceedings of 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2015), Vol.1, p.680 - 683, 2016/11
A two-dimensional scintillation neutron detector that has neutron-sensitive area of 64 64 cm was developed for neutron scattering instruments by using wavelength shifting fibers technology. We designed the detector to have a pixel size of 20 20 mm. In order to compensate light attenuation occurred travelling along the wavelength-shifting fiber the scintillation light was read out from both sides of the fiber. The prototype detector exhibited a detection efficiency of 40% for 1.8
neutrons, which was similar to previously developed detector with a smaller size of 32 32 cm. The detailed detector design and experimental results measured by using the pulsed neutrons at the J-PARC/MLF are presented.
To, Kentaro; Nakamura, Tatsuya; Sakasai, Kaoru; Yamagishi, Hideshi*
Proceedings of 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2015), 2 Pages, 2015/00
A two-dimensional gas-based neutron detector system that can be operated under high-pressure was developed, and an irradiation experiment was performed using a Cf-252 neutron source. The pressure vessel of the developed detector system has 256 feedthroughs insulated by alumina ceramics for neutron-induced signals and 6 connectors for high voltage. The vessel could withstand pressures of up to 0.8 MPa and with a helium leakage of less than 10
Pam
/s. The signals from neutrons clearly observed and can be discriminated from background signals such as 
-ray and electrical noises. The flat-field image showed good homogeneity and an average gain spread of approximately 7.7%. The system exhibits a -ray sensitivity of 1.110
.
Morishita, Yuki; Yamamoto, Seiichi*; Izaki, Kenji; Nemoto, Norio; Kashimuta, Yoshio*
no journal, ,
Nuclear fuel materials such as uranium and plutonium were handled at a nuclear fuel facility. Early detection of a contamination due to these materials is important to prevent internal exposure of workers. ZnS(Ag) scintillation detector has been widely used to detect these materials by measuring alpha-particles. It cannot directly measure narrow space. ZnS(Ag) scintillation detector does not have an ability to distinguish nuclear fuel materials from naturally occurring alpha emitters such as radon daughters. To solve this problem, we developed a new imaging detector named "flexible alpha camera". We actually measured plutonium specimen and radon daughters by the flexible alpha camera. In the result of 2-dimensional distribution, plutonium specimen was imaged as point. Spatial resolution of plutonium specimen was only 0.36 mm FWHM. Plutonium was distinguished from radon daughters based on differences of 2-dimensional distribution and energy by using the flexible alpha camera.
Tsubota, Yoichi; Waki, Takaaki*; Kaneko, Junichi*; Higuchi, Mikio*; Ishibashi, Hiroyuki*
no journal, ,
Gd
SiO
:Ce (GPS) is a rare-earth oxide scintillator with large light yield (LY) exceed NaI:Tl and can be used under high temp. environment. The triclinic La-GPS, which substituted Gd site for La, also have LY close to NaI:Tl. Although several trials on growth of La-GPS were reported, systematic research on LY were not sufficiently carried out. In this report, the optimization of La and Ce concentration of La-GPS was conducted to maximize LY. Sintered (LaxGd1-x-yCey)SiO (x= 0.1, y= 0 - 0.16) and (x= 0 - 0.15, y= 0.025) were fixed on glass plates and mechanically polished to be approx. 100 micro-meter thick. For the evaluation of scintillation LY, alpha-particle response measurement using 
Am was performed. For the Ce= 2.5% samples, La-GPS with 5 - 6.7% of La showed the highest LY. LY was then decreased as the La increased. For the La=10% samples, light yield increased as Ce increased in the range of Ce=0.5-2.5% that corresponded with the increase of luminescent center of Ce
. Decrease of LY due to concentration quenching was observed in the range of Ce
4%.
Kawachi, Naoki; Yin, Y.-G.; Suzui, Nobuo; Ishii, Satomi; Yoshihara, Toshihiro*; Watabe, Hiroshi*; Yamamoto, Seiichi*; Fujimaki, Shu
no journal, ,
Yamaguchi, Mitsutaka; Nagao, Yuto; Kawachi, Naoki; Fujimaki, Shu; Kamiya, Tomihiro; Torikai, Kota*; Shimada, Hirofumi*; Sugai, Hiroyuki*; Sakai, Makoto*; Arakawa, Kazuo*; et al.
no journal, ,
no abstracts in English
