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Journal Articles

Performance test of automatic analysis system of strontium-90 in environmental sample

Fujita, Hiroki; Nojima, Takehiro; Nagaoka, Mika; Osawa, Takahito; Yokoyama, Hiroya; Ono, Hironobu*

KEK Proceedings 2016-8, p.168 - 172, 2016/10

An automatic analysis system was developed to analyze Strontium-90 ($$^{90}$$Sr) radioactivity in environmental sample for 2013-2015. Various kinds of ashed environmental samples were used in performance tests of the automatic system. These tests were successful without any system trouble. However, $$^{90}$$Sr concentration had not been measured using the samples analyzed by the system. In this research, $$^{90}$$Sr concentration in seaweed sample was compared by between the system's analysis and worker's one. Moreover, the system was improved in each analysis process.

Journal Articles

Non-destructive depth analysis of the surface oxide layer on Mg$$_{2}$$Si with XPS and XAS

Esaka, Fumitaka; Nojima, Takehiro; Udono, Haruhiko*; Magara, Masaaki; Yamamoto, Hiroyuki

Surface and Interface Analysis, 48(7), p.432 - 435, 2016/07

 Times Cited Count:3 Percentile:88.48(Chemistry, Physical)

XPS is widely used for non-destructive chemical state analysis of solid materials. In this method, depth profiling can be carried out by a combination with ion beam sputtering. However, the sputtering often causes segregation and preferential sputtering of atoms and gives inaccurate information. The use of energy-tunable X-rays from synchrotron radiation (SR) enables us to perform non-destructive depth profiling in XPS. Here, the analytical depth can be changed by changing excitation X-ray energy. In the present study, we examined methods to perform depth profiling with XPS by changing excitation energy and XAS by changing electron energy for detection. These methods were then applied to the analysis of native surface oxide layers on Mg$$_{2}$$Si crystals. In this XAS analysis, the peak at 1843.4 eV becomes dominant when the electron energy for detection increases, which implies that Si-O or Si-O-Mg structure is formed as the surface oxide layer on the Mg$$_{2}$$Si.

Journal Articles

Development of automatic analysis system of Strontium-90 in environmental sample

Nojima, Takehiro; Fujita, Hiroki; Nagaoka, Mika; Osawa, Takahito; Yokoyama, Hiroya; Ono, Hironobu*

KEK Proceedings 2015-4, p.111 - 115, 2015/11

Automatic strontium-90 analysis system was developed for environmental sample in this research. The system was successful to do wet ashing, chemical separation and ion exchange processes using robot, automatic heating system and so on. Hand-made control program can operate the system by itself.

Journal Articles

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

Faenov, A.*; Matsubayashi, Masahito; Pikuz, T.*; Fukuda, Yuji; Kando, Masaki; Yasuda, Ryo; Iikura, Hiroshi; Nojima, Takehiro; Sakai, Takuro; Shiozawa, Masahiro*; et al.

High Power Laser Science and Engineering, 3, p.e27_1 - e27_9, 2015/10

 Times Cited Count:7 Percentile:50.14(Optics)

Journal Articles

Depth analysis of the surface of Mg$$_{2}$$Si crystals with XAS and XPS

Yamamoto, Hiroyuki; Nojima, Takehiro; Esaka, Fumitaka

Photon Factory Activity Report 2014, Part B, P. 112, 2015/00

In order to develop silicon-based electronic devices, metal silicides are widely studied. Information of the surface chemical states of metal silicides is important to obtain homo-epitaxial films with excellent quality. In this work, depth analysis of surface chemical states of Mg$$_{2}$$Si crystals is carried by XPS. Depth analysis is also performed in XAS measurement with a partial electron yield (PEY) mode. The Si 1s XPS spectra of the cleaved surface of the Mg$$_{2}$$Si crystal indicates that SiO is formed on the surface of the Mg$$_{2}$$Si crystal. Here, no peak assigned to SiO$$_{2}$$ structure is observed. The Si K-edge XAS spectra obtained with the PEY mode show a peak at 1843.7 eV, which can be assigned to SiO structure.

Journal Articles

Fabrication of fine imaging devices using an external proton microbeam

Sakai, Takuro; Yasuda, Ryo; Iikura, Hiroshi; Nojima, Takehiro; Koka, Masashi; Sato, Takahiro; Ishii, Yasuyuki; Oshima, Akihiro*

Nuclear Instruments and Methods in Physics Research B, 332, p.238 - 241, 2014/08

 Times Cited Count:0 Percentile:100(Instruments & Instrumentation)

We have successfully fabricated novel microscopic imaging devices made from UV/EB curable resin using an external scanning proton microbeams. The devices are micro-structured fluorescent plates that consist of an array of micro-pillars that align periodically. The base material used in the pillars is UV/EB curable resin and each pillar contains phosphor grains. The pattern exposures were performed using a proton beam writing technique. The height of the pillars depends on the range of the proton beam. Optical microscopy and scanning electron microscopy have been used to characterize the samples. The results show that the fabricated fluorescent plates are expected to be high-spatial-resolution imaging devices.

Journal Articles

Non-destructive depth profiling of Au/Si(100) with X-ray absorption spectroscopy

Yamamoto, Hiroyuki; Nojima, Takehiro; Esaka, Fumitaka

Photon Factory Activity Report 2013, Part B, P. 227, 2014/00

In the present study, we examined to perform depth profiling with X-ray absorption spectroscopy (XAS) by changing electron energies (5-50 eV) for detection in order to develop non-destructive depth profiling method with chemical state information. Gold thin films (1-10 nm) deposited on Si(100) were used for specimens. The Si/Au ratios were calculated from the peak heights of each edge using observed XAS spectra. Obvious correlation between the Si/Au ratio and the electron energy is observed. With decreasing electron energy, the ratio increased significantly. This means that by reducing electron energy, information on deeper region of the surface can be obtained. These results indicate that by changing electron energies for detection, it is possible to perform non-destructive depth profiling in XAS analysis.

Journal Articles

Micromachining of commodity plastics by proton beam writing and fabrication of spatial resolution test-chart for neutron radiography

Sakai, Takuro; Yasuda, Ryo; Iikura, Hiroshi; Nojima, Takehiro; Matsubayashi, Masahito; Kada, Wataru; Koka, Masashi; Sato, Takahiro; Okubo, Takeru; Ishii, Yasuyuki; et al.

Nuclear Instruments and Methods in Physics Research B, 306, p.299 - 301, 2013/07

 Times Cited Count:7 Percentile:41.73(Instruments & Instrumentation)

Journal Articles

A Line pair indicator made of Gd film for evaluating spatial resolution

Yasuda, Ryo; Matsubayashi, Masahito; Sakai, Takuro; Nojima, Takehiro; Iikura, Hiroshi; Katagiri, Masaki*; Takano, Katsuyoshi*; Pikuz, T.; Faenov, A.*

Physics Procedia, 43, p.196 - 204, 2013/00

 Times Cited Count:1 Percentile:41.32

Journal Articles

Investigation of the brightness enhancement using brightness enhancement films on a scintillator

Iikura, Hiroshi; Tsutsui, Noriaki*; Saito, Yasushi*; Nojima, Takehiro; Yasuda, Ryo; Sakai, Takuro; Matsubayashi, Masahito

Physics Procedia, 43, p.161 - 168, 2013/00

 Times Cited Count:2 Percentile:25.19

Journal Articles

Development of an imaging system for the observation of water behavior in a channel in PEFC

Nojima, Takehiro; Yasuda, Ryo; Takenaka, Nobuyuki*; Katagiri, Masaki*; Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito

Physics Procedia, 43, p.282 - 287, 2013/00

 Times Cited Count:2 Percentile:25.19

We developed a new imaging system for observing the water distribution in Polymer Electrolyte Fuel Cell (PEFC) under operation. This imaging system realizes both low noise and high sensitivity imaging and it enables to obtain an image in relatively short exposure time. This imaging system consists of EM-CCD (Electron Multiplication-Charged Coupled Device) camera, a LiF/ZnS scintillator screen and slit system. The EM-CCD camera has wide dynamic range and high sensitivity. The brightness of the scintillator screen is about three times higher than that of conventional type. The slit system was used for reducing the white dot noise caused by primary and/or secondary prompt $$gamma$$ rays. A characteristic test of this imaging system using JARI (Japan Automobile Research Institute)-standard cell was carried out at TNRF. In the results of the test, qualitative and quantitative observation of water behavior in the channel of PEFC was archived by the new imaging system.

Journal Articles

Development of a high-performance optical system and fluorescent converters for high-resolution neutron imaging

Sakai, Takuro; Yasuda, Ryo; Iikura, Hiroshi; Nojima, Takehiro; Matsubayashi, Masahito

Physics Procedia, 43, p.223 - 230, 2013/00

 Times Cited Count:0 Percentile:100

JAEA Reports

Arrangement of fuel cell system for TNRF

Nojima, Takehiro; Yasuda, Ryo; Takenaka, Nobuyuki*; Hayashida, Hirotoshi; Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito

JAEA-Technology 2011-037, 33 Pages, 2012/02

JAEA-Technology-2011-037.pdf:4.12MB

We have equipped fuel cell operation system for TNRF at JRR-3 in order to visualize on performance of PEFC. Our system, which is aimed to be used in nuclear facility, is composed by various equipments that give safety in experiments such as hydrogen diluting system and purge system, etc. We confirmed normal operation of our system with JARI-standard fuel cell, and succeeded in visualizing water distribution of fuel cell on performance by our system with neutron radiography.

Journal Articles

LiF crystals as high spatial resolution neutron imaging detectors

Matsubayashi, Masahito; Faenov, A. Ya.*; Pikuz, T.*; Fukuda, Yuji; Kato, Yoshiaki*; Yasuda, Ryo; Iikura, Hiroshi; Nojima, Takehiro; Sakai, Takuro

Nuclear Instruments and Methods in Physics Research A, 651(1), p.90 - 94, 2011/09

 Times Cited Count:6 Percentile:49.18(Instruments & Instrumentation)

Neutron imaging by color center formation in LiF crystals was applied to standard samples such as a sensitivity indicator (SI) for neutron radiography. The SI was exposed to 5 mm pinhole collimated thermal neutron beam with a LiF crystal and a neutron imaging plate (NIP) for 120 min in JRR-3 thermal neutron radiography facility. The image in NIP was read out with a readout resolution of 50 $$mu$$m. The image of SI in LiF crystal was read out with pixel size of 1.38 $$mu$$m using a laser confocal microscope. All gaps were clearly observed in the images for both LiF crystal and NIP, but small holes were not recognized for NIP. The experiment showed that LiF crystals had excellent characteristics as neutron imaging detectors such as high sensitivity, high spatial resolution, wide dynamic range and so on. In the paper, detailed characteristics of LiF crystals are compared with those of other neutron imaging detectors: NIP, a combination of fluorescent converter and cooled CCD camera.

Journal Articles

Evaluation of water distribution in a small operating fuel cell using neutron color image intensifier

Yasuda, Ryo; Nitto, Koichi*; Konagai, Chikara*; Shiozawa, Masahiro*; Takenaka, Nobuyuki*; Asano, Hitoshi*; Murakawa, Hideki*; Sugimoto, Katsumi*; Nojima, Takehiro; Hayashida, Hirotoshi; et al.

Nuclear Instruments and Methods in Physics Research A, 651(1), p.268 - 272, 2011/09

 Times Cited Count:7 Percentile:44.16(Instruments & Instrumentation)

Neutron radiography is one of useful tools to visualize water behavior in fuel cells under operation. In order to observe the detailed information about the water distribution in MEA and GDL in fuel cells, a high spatial resolution and high sensitivity neutron imaging system are required. We developed an imaging system using the neutron color imaging intensifier and continuously observed water distribution in operating a fuel cell. By using the system, a small type fuel cell under operation was continuously observed at the TNRF in every 20 sec. In the results, the water area was appeared from GDL and MEA, and expanded to the channel of the cathode side. On the other hand, voltage was gradually reduced with the operation time, and steeply dropped. It is considered that voltage drop was caused by blockage of gas flow due to the piling up water in the channel of the cathode side.

Journal Articles

Development of a small-aperture slit system for a high collimator ratio at the thermal neutron radiography facility in JRR-3

Yasuda, Ryo; Nojima, Takehiro; Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito

Journal of Nuclear Science and Technology, 48(7), p.1094 - 1101, 2011/07

 Times Cited Count:3 Percentile:69.54(Nuclear Science & Technology)

A small aperture system was developed and installed to enhance collimator ratio $$L$$/$$D$$ of the thermal neutron radiography facility (TNRF) in JRR-3. The small aperture system increases the $$L$$/$$D$$ by making small aperture $$D$$. Image sharpness was getting better with decreasing the aperture size below 10 mm by 10 mm in TNRF. The beam area of the small aperture slits was relatively small in comparison with that of the conventional large collimator, although gradually increasing with increasing the aperture size. Even 5 mm by 5 mm in aperture size, the practical beam area for imaging examinations corresponds to around 25 mm by 20 mm, which is enough area to carry out the high spatial resolution imaging.

Oral presentation

Visualization of water distribution in fuel cell using neutron radiography

Hayashida, Hirotoshi; Yasuda, Ryo; Honda, Mitsunori; Nojima, Takehiro; Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito; Shiozawa, Masahiro*; Nitta, Takahiro*; Isogai, Yuji*

no journal, , 

no abstracts in English

Oral presentation

Development of high spatial neutron radiography techniques for visualization inner fuel cells

Yasuda, Ryo; Hayashida, Hirotoshi; Sakai, Takuro; Honda, Mitsunori; Iikura, Hiroshi; Nojima, Takehiro; Matsubayashi, Masahito; Shiozawa, Masahiro*; Nitta, Takahiro*; Isogai, Yuji*

no journal, , 

Neutron radiography is an effective water diagnostic tool for fuel cells. For observation of water distribution in small region in fuel cells, improvement of spatial resolution of neutron radiography system is required. We fabricated the small aperture system for improvement of collimator ratio on Thermal Neutron Radiography Facility (TNRF) in JRR-3. In characteristic tests, better sharpness images were obtained by small aperture system compared with conventional radiography system.

Oral presentation

Evaluation of water distribution in a fuel cell under operation by neutron radiography

Yasuda, Ryo; Shiozawa, Masahiro*; Takenaka, Nobuyuki*; Asano, Hitoshi*; Hayashida, Hirotoshi; Sakai, Takuro; Honda, Mitsunori; Iikura, Hiroshi; Nojima, Takehiro; Matsubayashi, Masahito

no journal, , 

Neutron radiography is an effective water diagnostic tool for fuel cells. We continuously observed water behavior in a small type fuel cell under operation by high performance neutron radiography system using Neutron image intensifier. Water generated in the cell was initially accumulated in region of MEA and GDL, extending to a channel gradually. We will report and discuss about relationship between voltage drop and the water behavior in presentation.

Oral presentation

Development of new imaging system using fiber optics plate

Honda, Mitsunori; Yasuda, Ryo; Hayashida, Hirotoshi; Nojima, Takehiro; Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito

no journal, , 

no abstracts in English

47 (Records 1-20 displayed on this page)