Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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 (
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, Sr concentration had not been measured using the samples analyzed by the system. In this research, 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.
Si with XPS and XASEsaka, Fumitaka; Nojima, Takehiro; Udono, Haruhiko*; Magara, Masaaki; Yamamoto, Hiroyuki
Surface and Interface Analysis, 48(7), p.432 - 435, 2016/07
Times Cited Count：16 Percentile：38.77(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 MgSi 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 MgSi.
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.
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：10 Percentile：47.55(Optics)Si crystals with XAS and XPSYamamoto, 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 MgSi 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 MgSi crystal indicates that SiO is formed on the surface of the MgSi crystal. Here, no peak assigned to SiO 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.
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：2 Percentile：18.34(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.
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.
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：8 Percentile：51.20(Instruments & Instrumentation)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：5 Percentile：86.26(Physics, Applied)Sakai, Takuro; Yasuda, Ryo; Iikura, Hiroshi; Nojima, Takehiro; Matsubayashi, Masahito
Physics Procedia, 43, p.223 - 230, 2013/00
Times Cited Count：0 Percentile：0.00(Physics, Applied)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：68.06(Physics, Applied)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 
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.
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：52.06(Physics, Applied)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.
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：47.24(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.
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：9 Percentile：55.54(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 
m. The image of SI in LiF crystal was read out with pixel size of 1.38 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.
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：5 Percentile：37.18(Nuclear Science & Technology)A small aperture system was developed and installed to enhance collimator ratio 
/
of the thermal neutron radiography facility (TNRF) in JRR-3. The small aperture system increases the / by making small aperture . 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.
Yasuda, Ryo; Nojima, Takehiro; Matsubayashi, Masahito
no journal, ,
no abstracts in English
Nojima, Takehiro; Yasuda, Ryo; Takenaka, Nobuyuki*; Katagiri, Masaki*; Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito
no journal, ,
Polymer Electrolyte Fuel Cell (Fuel cell) is considered to be a future clean energy source because it discharges only water as by products. Fuel cells generate electricity with supply of oxygen and hydrogen gases. However, the water produced in fuel cells block the gas supply and the performance of fuel cell is lowered. Therefore, it is important for developments of fuel cells to understand the behavior of the produced water in fuel cells. Neutron radiography is a useful tool to visualize the distribution of the water in fuel cells. In this report, we valued correlation of back gas pressure and behavior of water behavior which are important parameter related to performance of PEFC by visualizing JARI standard PEFC on performance with NRG.
Honda, Mitsunori; Yasuda, Ryo; Hayashida, Hirotoshi; Nojima, Takehiro; Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito
no journal, ,
no abstracts in English
Sakai, Takuro; Yasuda, Ryo; Iikura, Hiroshi; Nojima, Takehiro; Matsubayashi, Masahito
no journal, ,
no abstracts in English
