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Nakamura, Tatsuya; Kawasaki, Takuro; To, Kentaro; Tsutsui, Noriaki; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru
Proceedings of 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2018) (Internet), 3 Pages, 2019/10
A two-dimensional scintillation neutron detector with a submillimeter spatial resolution was developed for pulsed neutron diffraction imaging at the J-PARC MLF. The detector comprised the thin, single ZnS/
LiF scintillator screen coupled with the crossed wavelength-shifting fiber array for light collection. For a high spatial resolution, the wavelength shifting fibers with diameter of 0.1 mm were used them for assembling the detector. The prototype detector that has a neutron-sensitive area of 24 
24 mm
exhibited a spatial resolution of 0.20
0.06 mm and 0.160.06 mm for x and y directions, respectively. The detector had a detection efficiency of 7
for thermal neutrons with a 
Co 
-ray sensitivity in the order of 10
. In this paper detailed detector design is presented together with experimental results using the pulsed neutron beam.
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Toh, Yosuke
Proceedings of 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2018) (Internet), 4 Pages, 2019/10
To, Kentaro; Nakamura, Tatsuya; Sakasai, Kaoru; Yamagishi, Hideshi*
no journal, ,
A bump cathode element that consists of a polyimide insulator and small-sized circular cathode bumps was developed, and an irradiation experiment was performed using a 
Cf neutron source. The sensitive area is 128 mm 128 mm with a pitch of 1 mm in both directions. The element was placed on the base plate that had multichannel connectors (X: 128 ch, Y: 128 ch) for signal transmission from the element to signal processing electronics mounted outside of the pressure vessel. The experiments were performed using a gaseous mixture of 
He and carbon tetrafluoride (CF
) at a total pressure of 0.7 MPa (He/ CF = 0.6/0.1). The neutron-induced signals of all pixels were observed using 128 128 ch test element, and the signal pulse peak of neutron can be observed in the pulse height distribution of anode wires. The signal pulse peak become high and the uniformity become well as the applied voltage increases.
Terasaka, Yuta; Sato, Yuki; Torii, Tatsuo
no journal, ,
A performance characteristics of plastic scintillation fiber (PSF) detector under high dose rate environment was evaluated for radiation distribution measurement inside Fukushima Daiichi Nuclear Power Station (FDNPS) buildings. A Time-of-Flight (TOF) method was applied to the 10 m long PSF (1 mm diameter, bundle number: 3) coupled with micro-photomultiplier for radiation distribution measurement. Position resolution of 48.2 cm (FWHM) at the center part of PSF was confirmed. The count rate of whole PSF increased with the dose rate increase up to approximately 45 mSv/h by adjusting constant fraction discriminator (CFD) threshold voltage.
