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Nakamura, Tatsuya; To, Kentaro; Tsutsui, Noriaki; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru
Proceedings of 2016 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2016), Vol.2, p.1506 - 1508, 2018/01
Position-dependent neutron sensitivity within an element of the scintillator / wavelength-shifting fiber coil (SFC) was evaluated by using a collimated pulsed neutron beam at the J-PARC/MLF. The collimated beam that has a size of 1 
1 mm
was scanned over the SFC element. The neutron counts were recorded and plotted in each incident position. The scanning results showed less neutron sensitivity at the juncture of the rolled scintillator, suggesting less light collection efficiency or a lack of scintillator materials due to imperfect manufacturing process.
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Tobita, Hiroshi; Kureta, Masatoshi; Koizumi, Mitsuo; Seya, Michio
Proceedings of 2016 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2016) (Internet), 4 Pages, 2016/00
no abstracts in English
To, Kentaro; Nakamura, Tatsuya; Sakasai, Kaoru; Yamagishi, Hideshi*
Proceedings of 2016 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2016) (Internet), 2 Pages, 2016/00
A ceramic-insulated ball-anode (CiB) element that consists of a ceramic insulator, cathode lines, ball-shaped anodes, and anode lines was developed, and an irradiation experiment was performed using a Cf-252 neutron source. An electric field simulation of CiB element was conducted and strong electric fields of more than 10
V/m was obtained by the calculation using the finite element method. The neutron-induced signals of all pixels were observed using 8 8 pixel small-sized test element under Cf-252 neutron irradiation.
Morishita, Yuki; Yamamoto, Seiichi*; Momose, Takumaro; Kaneko, Junichi*; Nemoto, Norio
no journal, ,
Plutonium dioxide (PuO
) is used to fabricate mixed oxide fuel for fast breeder reactors. When airborne contamination of Pu occurs, the presence of Pu in the nasal cavity of a worker should be instantly evaluated. The nasal smear method is usual method to immediately evaluate the intake of PuO at a work site. However, this method cannot evaluate the activity of Pu quantitatively because the removable factor of PuO can be changed by the nasal swab and the pressure of a finger. An alpha-particle detector that can directly measure the nasal cavity has not yet been developed. Therefore, we developed a nasal monitor that can directly measure the activity of Pu in the nasal cavity in order to exactly evaluate the internal exposure dose of a worker. For our device, a ZnS(Ag) scintillator was attached to the surface of a 3 mm 3 mm 20 mm prismatic-shaped light guide. A Silicon Photomultiplier (SiPM) array was used to detect the scintillation light from the ZnS (Ag) scintillator. 
Am source was collimated to 2 mm 5 mm and was used to evaluate the efficiency of the nasal monitor. Alpha particles were irradiated from three different faces to the scintillator for the left and right nasal cavities. In addition, the effects of gamma and beta rays on the nasal monitor were evaluated. The positions of both the left and right nasal cavities could be identified based on the two-dimensional distribution of the alpha particles. The average efficiency was comparable to the ZnS(Ag) scintillation survey meter. The effect of the gamma and beta rays was negligible for Pu monitoring. Considering these efficiencies and the self-absorption factor of alpha particles, the exact activity of Pu in the nasal cavity can be instantly evaluated.
NID) for energy-resolved neutron imaging with high rate and high spatial resolution at the J-PARC/MLFParker, J. D.*; Harada, Masahide; Hiroi, Kosuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Oikawa, Kenichi; Segawa, Mariko; Shinohara, Takenao; Su, Y. H.; Takada, Atsushi*; et al.
no journal, ,
