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Journal Articles

Evaluation of detector performances of new thin position-sensitive scintillation detectors for SENJU diffractometer

Nakamura, Tatsuya; To, Kentaro; Koizumi, Tomokatsu; Kiyanagi, Ryoji; Ohara, Takashi; Ebine, Masumi; Sakasai, Kaoru

Proceedings of 2022 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room Temperature Semiconductor Detector Conference (2022 IEEE NSS MIC RTSD) (Internet), 2 Pages, 2022/11

A new thin position-sensitive scintillation neutron detectors have been developed to replace present scintillation detectors in SENJU diffractometer at J-PARC MLF. The SENJU diffractometer originally composed of 37 position-sensitive detectors, where each detector has neutron sensitive area of 256 $$times$$ 256 mm with a pixel size of 4 $$times$$ 4 mm. To renew some original detectors the new detectors have been developed based on ZnS scintillator and wavelength-shifting fibers technology. The developed replacement detectors were designed with a thin thickness of 12 cm, which is 40% of the original detector. The new detectors have also improved detector performances to the original ones in terms of detection efficiency ($$sim$$60% for 2-A neutrons) and count uniformity (5-8%). The produced six detector modules have been implemented to the beamline after checking their detector performances in the lab.

Journal Articles

Two-dimensional scintillation neutron detectors for the extension of SENJU diffractometer

Nakamura, Tatsuya; To, Kentaro; Koizumi, Tomokatsu; Kiyanagi, Ryoji; Ohara, Takashi; Ebine, Masumi; Sakasai, Kaoru

Proceedings of 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2020), Vol.1, p.483 - 484, 2021/09

Two-dimensional neutron detectors were developed for the extension of SENJU time-of-flight Laue single crystal neutron diffractometer in J-PARC MLF. The detectors are to be installed at the additional detector bank for the SENJU instrument. The detector module is made based on ZnS scintillator and wavelength-shifting fiber technology, where each detector module maintains a neutron-sensitive area of 256$$times$$256 mm with a pixel size of 4$$times$$4 mm. To meet the tight space limitation in the instrument, the detector was designed as compact as possible. The detector has a depth of 170 mm, which is about 40% smaller than that of the original SENJU detector. All four produced detectors exhibited similar detector performances: detection efficiency 50-60% for 2-${AA}$ neutron, $$^{60}$$Co gamma-ray sensitivity 1$$times$$10$$^{-5}$$, count uniformity 3-6%.

Journal Articles

A Large area position-sensitive scintillation neutron detector for upgrading SENJU diffractometer

Nakamura, Tatsuya; To, Kentaro; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru

Proceedings of 2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2019), Vol.1, p.735 - 736, 2020/08

 Times Cited Count:0 Percentile:0.08

A large area, position-sensitive scintillation neutron detector was developed for upgrading the SENJU, time-of-flight Laue single crystal neutron diffractometer, in J-PARC MLF. The detector has a neutron-sensitive area of 512 $$times$$ 512 mm with a pixel size of 4 $$times$$ 4 mm. The detector was developed for upgrading of the SENJU instrument. The large area detector is to be installed below the vacuum tank to enlarge a covering solid angle. A $$^{6}$$Li:ZnS (Ag) scintillator and wavelength-shifting fiber technologies are employed. Each fiber channel is read out individually with photon counting mode. The electronics boards are implemented at the backside of the detector, enabling the detector depth as short as 20 cm. The detector exhibited a detection efficiency of 45% for thermal neutron. No degradation in fiber position and in neutron sensitivity has been observed over one year after production. In this paper, detector design and detector performances are presented.

Journal Articles

A Submillimeter spatial resolution scintillation detector for time-of-flight neutron diffraction imaging

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/$$^{6}$$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 $$times$$ 24 mm$$^{2}$$ exhibited a spatial resolution of 0.20$$pm$$0.06 mm and 0.16$$pm$$0.06 mm for x and y directions, respectively. The detector had a detection efficiency of 7$$%$$ for thermal neutrons with a $$^{60}$$Co $$gamma$$-ray sensitivity in the order of 10$$^{-6}$$. In this paper detailed detector design is presented together with experimental results using the pulsed neutron beam.

Journal Articles

Diagnosis of neutron sensitivity within a scintillator/wavelength-shifting fiber coil element by using a collimated pulsed neutron beam

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 $$times$$ 1 mm$$^{2}$$ 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.

Journal Articles

Development of a position-sensitive scintillation neutron detector for a new protein single-crystal diffractometer at J-PARC MLF

Nakamura, Tatsuya; To, Kentaro; Tsutsui, Noriaki; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru

Journal of Instrumentation (Internet), 12(12), p.C12025_1 - C12025_9, 2017/12

 Times Cited Count:1 Percentile:5.86(Instruments & Instrumentation)

A high-spatial-resolution, large-area position-sensitive scintillation-based neutron detector module has been developed for a new time-of-flight Laue single-crystal diffractometer to be constructed at J-PARC MLF. A first prototype detector implementing commercial $$^{6}$$Li:ZnS screens was produced based on a scintillator/wavelength-shifting fibre technology. The detector exhibited a spatial resolution of 2.5 mm with a neutron-sensitive area of 320 $$times$$ 320 mm$$^{2}$$. We report on an initial evaluation of the detector performance, including its spatial resolution, detection efficiency and long-term background measurement, and also provide a brief description of a new neutron instrument.

Journal Articles

A 64$$times$$64 cm$$^{2}$$ area position-sensitive scintillation neutron detector as an alternative to helium-3 gas based detector

Nakamura, 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 $$times$$ 64 cm$$^{2}$$ was developed for neutron scattering instruments by using wavelength shifting fibers technology. We designed the detector to have a pixel size of 20 $$times$$ 20 mm$$^{2}$$. 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${AA}$ neutrons, which was similar to previously developed detector with a smaller size of 32 $$times$$ 32 cm$$^{2}$$. The detailed detector design and experimental results measured by using the pulsed neutrons at the J-PARC/MLF are presented.

Journal Articles

A Two-dimensional scintillation-based neutron detector with wavelength-shifting fibers and incorporating an interpolation method

Nakamura, Tatsuya; To, Kentaro; Kawasaki, Takuro; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru; Soyama, Kazuhiko

Nuclear Instruments and Methods in Physics Research A, 784, p.202 - 207, 2015/06

 Times Cited Count:2 Percentile:17.75(Instruments & Instrumentation)

A two-dimensional scintillation neutron detector incorporating an interpolation method readout by wavelength-shifting (WLS) fiber was developed to make an effective pixel size smaller than the physical pitch of the WLS fibre array. The detector that was made with the crossed arranged WLS fiber arrays where the fibers were placed in a regular pitch of 2.5 mm in $$x$$ and $$y$$ directions. The dedicated signal processing algorithms that calculated an incident position of neutron with a base length of the same, half and quarter of the physical WLS fiber pitch were developed for the detector operated in a photon-counting method. The paper demonstrated the feasibility of the developed interpolation method using a collimated neutron beam.

Journal Articles

Development of a wavelength-shifting-fibre-based scintillator neutron detector as an alternative to $$^{3}$$He at J-PARC/MLF

Nakamura, Tatsuya; To, Kentaro; Honda, Katsunori; Birumachi, Atsushi; Ebine, Masumi; Sakasai, Kaoru; Soyama, Kazuhiko; Katagiri, Masaki*

Journal of Physics; Conference Series, 528, p.012042_1 - 012042_7, 2014/07

 Times Cited Count:4 Percentile:87.94

A wavelength-shifting fiber based scintillator detector has been developed as a helium-3 alternative detector in J-PARC/MLF. The detector is aimed at using for an inelastic neutron scattering instrument in a pulsed neutron source. The detector should have a capability to have a large-area coverage with a moderate pixel size as well as high detector efficiency, low $$gamma$$ sensitivity, and a low background rate. We have developed a detector that has a larger neutron-sensitive area with a moderate pixel size based on the detector implemented in the SENJU instrument in the J-PARC/MLF. The prototype detector has a pixel size of 20 $$times$$ 20 mm with a neutron-sensitive area of 320 $$times$$ 320 mm. In the presentation detailed detector performances are presented in comparison to those measured by an original SENJU detector.

Journal Articles

Neutron-sensitive ZnS/$$^{10}$$B$$_{2}$$O$$_{3}$$ ceramic scintillator detector as an alternative to a $$^{3}$$He-gas-based detector for a plutonium canister assay system

Nakamura, Tatsuya; Ozu, Akira; To, Kentaro; Sakasai, Kaoru; Suzuki, Hiroyuki; Honda, Katsunori; Birumachi, Atsushi; Ebine, Masumi; Yamagishi, Hideshi*; Takase, Misao; et al.

Nuclear Instruments and Methods in Physics Research A, 763, p.340 - 346, 2014/05

 Times Cited Count:3 Percentile:27.07(Instruments & Instrumentation)

A neutron-sensitive ZnS/$$^{10}$$B$$_{2}$$O$$_{3}$$ ceramic scintillator detector was developed as an alternative to a $$^{3}$$He-gas-based detector for use in a plutonium canister assay system. The detector has a modular structure, with a flat ZnS/$$^{10}$$B$$_{2}$$O$$_{3}$$ceramic scintillator strip that is installed diagonally inside a light-reflecting aluminium case with a square cross section. The prototype detectors, which have a neutron-sensitive area of 30 mm $$times$$ 250 mm, exhibited a sensitivity of 21.7-23.4 $$pm$$ 0.1 cps$$/$$nv for thermal neutrons, a $$^{137}$$Cs $$gamma$$-ray sensitivity of 1.1-1.9 $$pm $$0.2 $$times$$ 10$$^{-7}$$ and a count variation of less than 6% over the detector length. A trial experiment revealed a temperature coefficient of less than -0.24$$pm$$ 0.05% / $$^{circ}$$C over the temperature range of 20-50$$^{circ}$$C.

Journal Articles

A Position-sensitive tubular scintillator-based detector as an alternative to a $$^{3}$$He-gas-based detector for neutron-scattering instruments

Nakamura, Tatsuya; Katagiri, Masaki*; To, Kentaro; Honda, Katsunori; Suzuki, Hiroyuki; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru; Soyama, Kazuhiko

Nuclear Instruments and Methods in Physics Research A, 741, p.42 - 46, 2014/03

 Times Cited Count:6 Percentile:48.56(Instruments & Instrumentation)

A position-sensitive tubular scintillator-based neutron detector is proposed as an alternative to a $$^{3}$$He-gas-based detector. The detector has a neutron-detecting element constructed from rolled ZnS/$$^{6}$$LiF scintillator screens that sandwich wavelength-shifting (WLS) fibre coils (SFC element). Multiple SFC elements are enclosed in an aluminium tube in a row to form a one-dimensional position-sensitive neutron detector. The design of the WLS fibre coil, which was determined by performing basic experiments, comprised two 0.75-mm-diameter WLS fibres wound in parallel at a pitch of 1.5 mm. A 64-element detector with a pixel size of 22 mm $$times$$ 20 mm (width $$times$$ length) successfully demonstrated the detection principle. The tubular shape of the new detector is similar to the usual 25-mm-diameter $$^{3}$$He tube, making this an alternative detector with the potential to be installed in a vacuum tank for inelastic-neutron-scattering instruments.

Journal Articles

A Scintillator-based detector with sub-100-$$mu$$m spatial resolution comprising a fibre-optic taper with wavelength-shifting fibre readout for time-of-flight neutron imaging

Nakamura, Tatsuya; To, Kentaro; Kawasaki, Takuro; Honda, Katsunori; Suzuki, Hiroyuki; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru; Soyama, Kazuhiko; Katagiri, Masaki*

Nuclear Instruments and Methods in Physics Research A, 737, p.176 - 183, 2014/02

 Times Cited Count:13 Percentile:70.4(Instruments & Instrumentation)

Journal Articles

Detector system of the $$SENJU$$ single-crystal time-of-flight neutron diffractometer at J-PARC/MLF

Kawasaki, Takuro; Nakamura, Tatsuya; To, Kentaro; Hosoya, Takaaki*; Oikawa, Kenichi; Ohara, Takashi; Kiyanagi, Ryoji; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru; et al.

Nuclear Instruments and Methods in Physics Research A, 735, p.444 - 451, 2014/01

 Times Cited Count:18 Percentile:80.26(Instruments & Instrumentation)

Journal Articles

A Time-of-flight neutron imaging detector using ZnS/$$^{6}$$LiF scintillator and wavelength shifting fibers with high spatial resolution and with low gamma-ray sensitivity

Nakamura, Tatsuya; To, Kentaro; Kawasaki, Takuro; Honda, Katsunori; Birumachi, Atsushi; Ebine, Masumi; Sakasai, Kaoru; Soyama, Kazuhiko; Katagiri, Masaki*

Proceedings of 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference; 21st International Symposium on Room-Temperature Semiconductor X-ray and $$gamma$$-ray detectors (NSS/MIC 2014), p.1751 - 1753, 2014/00

The ZnS scintillator-based two-dimensional detector was developed for a time-of-flight neutron imaging with a high spatial resolution and a low $$gamma$$-ray sensitivity. The detector is comprised of a thin ZnS scintillator with crossed wavelength-shifting-fibers (WLS fibers) arrays equipped with the fiber optic taper (FOT). The developed detector based on a neutron counting method has a high spatial resolution of less than 100 um (in FWHM) with a moderate count rate capability of several tens of thousands of cps. Of particular interest is its low $$gamma$$-ray sensitivity of 10$$^{-7}$$. Imaging capabilities of the detector are demonstrated by using a high-intensity pulsed neutron beam at the Materials and Life Science Experimental Facility in the Japan Proton Accelerator Complex (J-PARC/MLF).

Journal Articles

Evaluation of angular dependence of neutron detection efficiencies of ZnS scintillator detectors

Nakamura, Tatsuya; To, Kentaro; Kawasaki, Takuro; Honda, Katsunori; Suzuki, Hiroyuki; Ebine, Masumi; Birumachi, Atsushi; Sakasai, Kaoru; Soyama, Kazuhiko; Katagiri, Masaki*

Proceedings of 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC), Vol.4, p.2367 - 2369, 2013/00

The detection efficiency of a ZnS-based neutron scintillator detector was evaluated as a function of the incident angle and the wavelength of a neutron. A pulsed neutron beam that has a wavelength from 1 to 8${AA}$ was incident to the test detector that implemented a ZnS/$$^{6}$$LiF and ZnS/$$^{10}$$B$$_{2}$$O$$_{3}$$ scintillator that have thicknesses of 0.45 and of 0.20 mm, respectively. In each scintillator the detection efficiency increased as the incident angle increased for neutrons with a wavelength shorter than about 3${AA}$. A comparison between the experimental results and the model fitting are presented.

Journal Articles

A Large-area two-dimensional scintillator detector with a wavelength-shifting fibre readout for a time-of-flight single-crystal neutron diffractometer

Nakamura, Tatsuya; Kawasaki, Takuro; Hosoya, Takaaki*; To, Kentaro; Oikawa, Kenichi; Sakasai, Kaoru; Ebine, Masumi; Birumachi, Atsushi; Soyama, Kazuhiko; Katagiri, Masaki*

Nuclear Instruments and Methods in Physics Research A, 686, p.64 - 70, 2012/09

 Times Cited Count:30 Percentile:90.43(Instruments & Instrumentation)

A two-dimensional scintillator-based neutron detector that has a neutron-sensitive area of 256 $$times$$ 256 mm$$^{2}$$ with a pixel size of 4 mm was developed. The detector was designed to be compact and modular with the smallest dead area for the SENJU time-of-flight Laue single-crystal diffractometer to be constructed in the Materials and Life Experimental Science Facility at the Japanese Proton Accelerator Research Complex. Two ZnS/$$^{10}{B}_{2}{O}_{3} $$ scintillator screens with an optimized scintillator thickness sandwiched the cross-arranged Wavelength-shifting fibre arrays to ensure a high detection efficiency for thermal neutrons. The prototype detector exhibited a detector efficiency of 40 $$pm$$ 1 % for 1.6-${AA}$ neutrons and a $$^{60}$$Co $$gamma$$-ray sensitivity of 6.0$$pm$$0.1 $$ times$$ $${10}^{-6}$$, which fulfilled the required detector specifications for SENJU.

Journal Articles

Development of wavelength-shifting-fiber neutron image detector with a fiber-optic taper with a high spatial resolution

Nakamura, Tatsuya; Yasuda, Ryo; Katagiri, Masaki*; To, Kentaro; Sakasai, Kaoru; Birumachi, Atsushi; Ebine, Masumi; Soyama, Kazuhiko

Proceedings of 2011 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2011), Vol.1, p.382 - 384, 2011/00

The neutron image detector that was based on wavelength-shifting-fibers (WLS fibres) equipped with the fibre optic taper (FOT) was developed. By inserting the FOT in between the scintillator and WLS fibers the measured neutron image was magnified on the WLS fibres, resulting in better spatial resolution. We have tested two FOTs; a square shaped one in a size of 2.6 $$times$$ 2.6 mm and a round shaped with a diameter of 20 mm. Both FOTs have identical magnification ratios of 3.1. By implementing the larger FOT the detector has the neutron-sensitive area of 314 mm$$^{2}$$ with the effective pixel size of 0.17 $$times$$ 0.17 mm$$^{2}$$ whilst the light transmission rate decreased 20% less compared to that with the small FOT. The detector equipped with the larger FOT exhibited a spatial resolution of 0.26 $$pm$$ 0.07 mm, which was similar to the one with the small FOT.

Journal Articles

Wavelength-shifting-fibre-based neutron image detector with a fibre-optic taper to increase the spatial resolution

Nakamura, Tatsuya; Katagiri, Masaki; To, Kentaro; Sakasai, Kaoru; Ebine, Masumi; Birumachi, Atsushi; Soyama, Kazuhiko

Nuclear Instruments and Methods in Physics Research A, 604(1-2), p.158 - 160, 2009/06

 Times Cited Count:8 Percentile:50.64(Instruments & Instrumentation)

The effective pixel size of a two-dimensional wavelength-shifting-fibre (WLS-fibre)-based neutron image detector was improved from 0.5 to 0.16 mm by including a fibre-optic taper (FOT) between the scintillator screen and the WLS fibre. The WLS-fibre-based detector consisted of a thin ZnS/$$^{6}$$LiF screen, a FOT and WLS ribbons crossed in the x and y directions. The demonstrator detector had 16 fibre channels in each direction, and the light signals in each fibre were read out individually. The FOT was constructed from fine glass fibres with a taper ratio of 3.1, and served as an image magnifier. The prototype detector equipped with the FOT exhibited a spatial resolution of 0.3 mm, compared to the spatial resolution of 0.8 mm for the original detector without the FOT.

JAEA Reports

Development for upgrading Japanese ENGIN-X type linear scintillation neutron detectors; Development of new ZnS scintillator, light reflector and digital signal processing module

Nakamura, Tatsuya; Katagiri, Masaki; Birumachi, Atsushi; Ebine, Masumi; Tsutsui, Noriaki*; Soyama, Kazuhiko; Schooneveld, E. M.*; Rhodes, N. J.*

JAEA-Research 2008-116, 26 Pages, 2009/03

JAEA-Research-2008-116.pdf:4.25MB

New ZnS scintillator, light reflector and digital signal processing modules were developed to upgrade the Japanese ENGIN-X type linear scintillation neutron detector. The developed ZnS/$$^{10}$$B$$_{2}$$O$$_{3}$$ scintillator improved detector efficiency by a factor 1.2 for neutrons with a wavelength of 1 ${AA}$ whilst the detector maintained similar $$gamma$$ sensitivity and multi-count ratio compared to the present AST (4:1) scintillator. The paint coating less light reflector was developed with an aluminum reflector with etched surface. The detector implemented with this reflector exhibited similar detector performances with paint coating reflectors, confirming feasibility of the reflector with long-term stability. The digital signal-processing module incorporating photon-counting method was successfully developed. The fully digitalized photon counting system improved a temperature stability of neutron counts significantly comparing to the present analogue system.

JAEA Reports

Development of two-dimensional scintillator neutron detector using wavelength-shifting fibres; Development of a compact detector for iBIX instrument in J-PARC/MLF

Nakamura, Tatsuya; Katagiri, Masaki; Hosoya, Takaaki*; Birumachi, Atsushi; Ebine, Masumi; Soyama, Kazuhiko; Schooneveld, E.*; Rhodes, N.*

JAEA-Research 2008-115, 33 Pages, 2009/03

JAEA-Research-2008-115.pdf:3.77MB

A compact two-dimensional neutron detector was developed for iBIX instrument in the J-PARC/MLF. The specifications required for the detector were a spatial resolution of less than 1 mm, a detector efficiency of more than 50% for thermal neutrons, a $$gamma$$ sensitivity of less than 10$$^{6}$$, detector coverage of around 15$$times$$15 cm$$^{2}$$ with least dead area, compactness, modularity, and a pulse pair resolution of less than 2 $$mu$$s. The detector components were studied in detail and optimized for the purpose. The compact prototype detector that has a neutron sensitive area of 13.3$$times$$13.3 cm$$^{2}$$ was made and feasibility of the detector was demonstrated successfully in the experiments at the ISIS pulsed neutron source.

65 (Records 1-20 displayed on this page)