M. Matsubayashi’s research while affiliated with Japan Atomic Energy Agency and other places

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Publications (73)


Introduction to Neutron Radiography Facilities at the Japan Research Reactor-3
  • Article
  • Full-text available

September 2023

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91 Reads

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2 Citations

Journal of Physics Conference Series

K Kurita

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Y Tsuchikawa

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M Matsubayashi

The Japan Research Reactor-3 (JRR-3) resumed its operations on February 26, 2021, and user program was restarted in July 2021. With the resumption of JRR-3 operation, two imaging facilities, the Thermal Neutron Radiography Facility (TNRF) and the Cold Neutron Radiography Facility (CNRF), have also resumed operations. At the TNRF, the imaging detection system, i.e. the cameras and light-tight boxes, has been updated, and the imaging performance has been investigated. The spatial resolution was measured using imaging plates at the CNRF. In this manuscript, we report the details of these two neutron facilities.

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Figure 2. Principles of neutron imaging generation in LiF crystals.  
Figure 3. In image readout, luminescence from the LiF crystal was observed with a laser scanning confocal luminescence microscope. The λ = 488 nm line of an argon laser was used for excitation and luminescence from the CCs at λ > 510 nm [33–36] .  
Figure 4. Schematic diagrams and sizes of the line pairs produced on 5 µm thickness Gd patterns coated onto the overall surface of a glass substrate and their images obtained by using the LiF crystal neutron imaging detector (top). Line-pair images obtained using the LiF single crystal detector and line profiles of the pairs with widths of 10 µm [36] (bottom). The spatial resolution on the scale of 5 µm is clearly seen.  
Figure 5. (a) Neutron image of a 100 µm thick Cd plate taken with 10 s exposure time and a trace of the neutron image across the edge, which is compared
Figure 6. (a) Comparison of the neutron images of the Au wires of 42, 95 and 287 µm diameter recorded with exposure times of 10 and 30 min [33] .

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Using LiF crystals for high-performance neutron imaging with micron-scale resolution

October 2015

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227 Reads

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12 Citations

High Power Laser Science and Engineering

This paper describes an overview of our recent discovery – clear demonstration that LiF crystals can be efficiently used as a high-performance neutron imaging detector based on optically stimulated luminescence of color centers generated by neutron irradiation. It is shown that the neutron images we have obtained are almost free from granular noise, have a spatial resolution of 5.4 μm{\sim}5.4~{\rm\mu}\text{m} and a linear response with a dynamic range of at least 10310^{3} . The high contrast and good sensitivity of LiF crystals allow us to distinguish two holes with less than 2% transmittance difference. We propose to use such detectors in areas where high spatial resolution with high image gradation resolution is needed, including diagnostics of different plasma sources such as laser and z-pinch produced plasmas.


A Line Pair Indicator Made of Gd Film for Evaluating Spatial Resolution

December 2013

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62 Reads

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4 Citations

Physics Procedia

A device for evaluating the spatial resolution of a neutron imaging system was developed. Using laser processes, line-pair patterns were fabricated on a 0.005-mm-thick Gd film evaporated on a glass plate. Large line pairs of widths ranging from 0.2 to 2 mm were machined using an Nd:YVO4 laser (0.03 mm spot size) and displayed on a brightness field, while small line pairs of widths ranging from 0.01 to 0.1 mm were created using an eximer laser on a dark field. A scanning electron microscope (SEM) observation determined that, although the large line pairs machined using the Nd: YVO4 laser were chipped on the corners of the Gd bars, the difference between the measured and designed line-pair widths was controlled absolutely within 0.02 mm. In the small line pairs of less than 0.1 mm width processed using the eximer laser, edges sharper than those of the large line pairs were formed. In neutron imaging tests using a LiF/ZnS(Ag) scintillator and a CCD camera system, good contrast images were obtained with the brightness field, even at 0.005 mm thickness. The small line pairs on the dark field were observed using a LiF single crystal detector having an ultra-high spatial resolution of approximately 0.005 mm. Splits in the small line pairs of as little as 0.01 mm wide were shown with good contrast on the images. (C) 2013 The Authors. Published by Elsevier B.V.


Table 1 . Configuration of the BEFs 
Fig. 1. Neutron imaging system at the E-2 beam port at the KURRI. 
Fig. 2. Experimental setting for the BEF (left) and the structure of a BEF (right). 
Fig. 3. Comparison of the brightness as a function of the type of BEF. The error bars represent the standard deviation. 
Fig. 4. Neutron transmission images of the Gd-resolution mask No. 2 (a) without a BEF, (b) with BEF-1, and (c) with BEF-2; 
Investigation of the Brightness Enhancement using Brightness Enhancement Films on a Scintillator

December 2013

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276 Reads

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6 Citations

Physics Procedia

In neutron imaging, enhancing the brightness of a neutron detector is an important factor for shortening the imaging time and improving the image quality. Recently, we devised a technique for increasing the light intensity received on a camera by adding brightness enhancement films (BEFs) on the output surface of a scintillator. Using a BEF (BEF II 90/24, Vikuiti 3M), the brightness was enhanced, but the spatial resolution was reduced. In this study, we investigated the brightness and spatial resolution using several types of BEFs with different thicknesses and prism pitches. No correlation between the brightness and the film thickness, and between the brightness and the prism pitch, was recognized. For the spatial resolution, however, when the film thickness was reduced, the spatial resolution was observed to improve. (C) 2013 The Authors. Published by Elsevier B.V.


Development of an Imaging System for the Observation of Water Behavior in a Channel in PEMFC

December 2013

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20 Reads

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5 Citations

Physics Procedia

A new imaging system was developed for observing water distribution in a polymer electrolyte membrane fuel cell (PEMFC) under operation. This imaging system realizes both low-noise and high-sensitivity imaging, enables image capture with a relatively short exposure time (approximately sub-seconds) and effectively visualizes the internal events of a PEMFC. It consists of an electron multiplying charge coupled device (EMCCD) camera, new 6LiF/ZnS scintillator screen, and slit system. The EMCCD camera has a wide dynamic range and high sensitivity, and the brightness of the new 6LiF/ZnS scintillator screen is approximately twice as high as that of conventional 6LiF/ZnS scintillator screen. The slit system is used to reduce the white dot noise caused by the primary and/or secondary prompt gamma rays. By a characteristic test, it was demonstrated that water behavior in the channel of a PEMFC can be clearly and qualitatively observed using the new imaging system.


Development of a High-performance Optical System and Fluorescent Converters for High-resolution Neutron Imaging

December 2013

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78 Reads

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1 Citation

Physics Procedia

Two novel devices for use in neutron imaging technique are introduced. The first one is a high-performance optical lens for video camera systems. The lens system has a magnification of 1:1 and an F value of 3. The optical resolution is less than 5 mu m. The second device is a high-resolution fluorescent plate that converts neutrons into visible light. The fluorescent converter material consists of a mixture of (LiF)-Li-6 and ZnS(Ag) tine powder, and the thickness of the converter is material is as little as 15 mu m. The surface of the plate is coated with a 1 mu m-thick gadolinium oxide layer. This layer is optically transparent and acts as an electron emitter for neutron detection. Our preliminary results show that the developed optical lens and fluorescent converter plates are very promising for high-resolution neutron imaging. (C) 2013 The Authors. Published by Elsevier B.V.


Present Status of Research on Pulsed Neutron Imaging in Japan

December 2013

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84 Reads

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20 Citations

Physics Procedia

Pulsed neutron imaging methods provide information on crystallographic structure, magnetic field, elemental composition, hydrogen bound state and other material features. Such methods have been expected to be a powerful complement to the traditional imaging method. Data analysis codes, detectors and new applications are being developed in Japan, and a new imaging beam line is being constructed at J-PARC. Here, recent progress in Japanese research on pulsed neutron imaging is presented, and a design for construction of the new imaging beam line is reported. (C) 2013 The Authors. Published by Elsevier B.V.


Influence of powder particle size and scintillator layer thickness on the performance of Gd2O2S:Tb scintillators for neutron imaging

July 2012

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114 Reads

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27 Citations

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment

The neutron-capture cross-section of Gd2O2S:Tb scintillators is considerably higher than that of ZnS/LiF scintillators, which are commonly used in neutron radiography. The characteristics of these powder-type Gd2O2S:Tb scintillators correlate to some material parameters, including scintillator layer thickness and powder size. Three types of Gd2O2S:Tb scintillators with different powder particle sizes were prepared, and the effects of the powder size and scintillator layer thickness on the scintillator characteristics were evaluated using a sensitivity indicator (SI) and a beam purity indicator (BPI). The intensity of scintillation increased as the particle size increased. In addition, the intensity of scintillation detected saturated at a specific thickness for each scintillator particle size. This saturation was considered to be caused by differences in the packing rate of the powder near the substrate and the flight paths of thermal neutrons and internal conversion electrons in the scintillator. Additionally, the image quality worsened with increasing scintillator layer thickness. On the basis of our investigation, we determined the optimum powder particle size and layer thickness of the Gd2O2S:Tb scintillator for neutron imaging.


Micromachining of Commodity Plastics by Proton Beam Writing and Fabrication of Spatial Resolution Test-chart for Neutron Radiography

January 2012

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16 Reads

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8 Citations

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms

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R. Yasuda

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others

Proton beam writing is a direct-write technique and a promising method for the micromachining of commodity plastics such as acrylic resins. Herein, we describe the fabrication of microscopic devices made from a relatively thick (∼75 μm) acrylic sheet using proton beam writing. In addition, a software package that converts image pixels into coordinates data was developed, and the successful fabrication of a very fine jigsaw puzzle was achieved. The size of the jigsaw puzzle pieces was 50 × 50 μm. For practical use, a prototype of a line and space test-chart was also successfully fabricated for the determination of spatial resolution in neutron radiography.


Design study of the imaging beam line at J-PARC MLF, ERNIS

September 2011

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85 Reads

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16 Citations

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment

We have a plan to build an imaging beam line, Energy-Resolved Neutron Imaging System (ERNIS), at Materials and Life Science Experimental Facility (MLF) at Japan Proton Accelerator Research Complex (J-PARC). In pulsed neutron imaging, we use characteristic features of the neutron total cross section, depending on the neutron wavelength, to get sample information such as crystallographic structure and nuclide composition. One of the most important items to be determined for a beam line at J-PARC is the choice of moderator among coupled, decoupled, and poisoned moderators. From the wavelength resolution point of view, we decided to use the decoupled moderator, which could cover major experiments performed at a pulsed neutron source. Here, we discuss the structure of the imaging beam line at beam line 22 of the J-PARC neutron source as well as the arrangement of insertion devices and the experimental area.


Citations (49)


... The process involved using aluminium alloy tubes to allow for a neutron beam to perpendicularly penetrate the pipe. This neutron beam was proportionately attenuated by the encountered hydrogen within the water phase along its path and able to project an image of the residing twophase flow that could then be converted to an optical image [50,51]. Schmidt et al. [52] employed a gamma ray system following the same basic principles. ...

Reference:

A critical review of flow maps for gas-liquid flows in vertical pipes and annuli
Application of neutron radiography to visualization and void fraction measurement of air-water two-phase flow in a small diameter tube
  • Citing Article
  • January 1993

Journal of Nuclear Science and Technology

... In order to design the Na/Pb-Bi/H 2 O steam generator, Furuya, Kinoshita and co-workers [99][100][101][102][103][104][105][106][107][108] have extensively investigated and reported on the heat transfer characteristics and phenomena associated with direct contact heat transfer and vapor explosions issues of relevance to an innovative steam generator design. ...

Visualization of direct contact heat transfer between molten alloy and water by neutron radiography
  • Citing Article
  • January 1998

... In acidic soil, one of the main reasons for the slow growth of plants is the toxicity of aluminum. Modification experiment of sulfonation and oxygenation of lignin was conducted by Saito et al. (1997). The product can adsorb aluminum ion in the soil, can be used to improve the soil with high salt content, reshape the soil aggregate structure, improve the soil permeability and improve the fertilizer efficiency. ...

Development of New Lignin Derivatives as Soil Conditioning Agents by Radical Sulfonation and Alkaline-Oxygen Treatment
  • Citing Article
  • January 1997

... The size of tracer particle is rather large compared with the bed materials, but the traceability is expected to be good because of very high effective viscosity of the ¯uidized bed (Ozawa et al. 1996a ). The detailed discussion on the tracer particles can be found elsewhere (Umekawa et al. 1999 ). The minimum ¯uidization velocity was J Gmf ˆ 0:103 m/s at the stagnant bed height 340 mm without tube banks. ...

Heat transfer in cross-flow tube-banks immersed in a fluidized-bed with normal and down-flow mode operations
  • Citing Article
  • January 1999

... Many demands exist for high-spatial-resolution neutron radiography of less than 10 µm, and various approaches are being developed to improve the resolution of neutron radiography: optical magnification [3][4][5], event centroiding [6][7][8], track recording [9,10], and neutron focusing techniques [11]. Optical magnification systems have been recently developed by the Paul Scherrer Institut (PSI) group, achieving resolutions of 10 µm by a fiber optics taper [3] and 5 µm by a neutron microscope [4,5]. ...

Using LiF crystals for high-performance neutron imaging with micron-scale resolution

High Power Laser Science and Engineering

... Then, the line profile of each image across the middle was taken out to show the dissection image of water in the disk. The pattern of decreasing moisture on the plane of the disk showed that the moisture RelaƟve amount RelaƟve amount Fig. 1.26 Water image of the cedar tree during the drying process [11]. Wood disks of cedar trees, which were 1 cm thick, were removed every 2 h during the drying process, and neutron images were obtained. ...

Three Dimensional Imaging of Moisture in Wood Disk by Neutron Beam during Drying Process
  • Citing Article
  • January 1998

Holzforschung

... Although the L/D of the TNRF is not very high, measurements with a high L/D are possible using a small-aperture slit system installed in the imaging room TNRF-I [5]. Using this system, L/D can be increased to approximately 1000; however, the FOV and neutron flux become extremely small [6]. By contrast, an energy-resolved neutron imaging system called RADEN at the Materials and Life Science Experimental Facility in the J-PARC, located at the same site as JRR-3, can simultaneously provide a high L/D, high neutron flux, and wide FOV [7]. ...

Development of an Imaging System for the Observation of Water Behavior in a Channel in PEMFC

Physics Procedia

... Additionally, the Crystals 2024, 14, 922 3 of 18 optical distance (OD) between the backlight and the LCD panel is also required to eliminate hotspots and achieve the uniform luminance distribution. The upper surface of the BEF features a prism structure in order to reduce the angle of light reaching the bottom surface of the LCD panel [15]. ...

Investigation of the Brightness Enhancement using Brightness Enhancement Films on a Scintillator

Physics Procedia

... The CNRF imaging room is much smaller than that of the TNRF, approximately 650 mm (W) × 850 mm (H) × 600 mm (D). Only imaging systems using imaging plates (IPs) are currently available at the CNRF. Figure 4 shows a neutron transmission image of a Gd test pattern [18] obtained using an IP at the CNRF. The IP attached to the test pattern is moved across the neutron beam with an exposure time of approximately 10 s. ...

A Line Pair Indicator Made of Gd Film for Evaluating Spatial Resolution

Physics Procedia