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Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Kajimoto, Ryoichi; Takahashi, Nobuaki*; Nakamura, Mitsutaka; Soyama, Kazuhiko; Osakabe, Toyotaka
EPJ Web of Conferences, 83, p.03011_1 - 03011_5, 2015/01
Times Cited Count：3 Percentile：73.13We report the design of the beam-transport system (especially the vertical geometry) for a cold-neutron disk-chopper spectrometer AMATERAS at J-PARC. Based on the elliptical shape, which is one of the most effective geometries for a ballistic mirror, the design was optimized to obtain, at the sample position, a neutron beam with high flux without serious degrading in divergence and spacial homogeneity within the boundary conditions required from actual spectrometer construction. The optimum focal point was examined. An ideal elliptical shape was modified to reduce its height without serious loss of transmission. The final result was adapted to the construction requirements of AMATERAS. Although the ideas studied in this paper are considered for the AMATERAS case, they can be useful also to other spectrometers in similar situations.
Otsuka, Noriaki; Takeuchi, Tomoaki; Yamamoto, Keiichi; Shibata, Akira; Kimura, Nobuaki; Takemoto, Noriyuki; Tanimoto, Masataka; Tsuchiya, Kunihiko; Sano, Tadafumi*; Unesaki, Hironobu*; et al.
KURRI Progress Report 2013, P. 215, 2014/10
Investigation of a relation between reactor power and brightness of Cherenkov light at Kyoto University Research reactor (KUR) by a CCD camera was performed due to a development of a real-time in-core measurement technique using Cherenkov light. Analyzing the brightness value of individual RGB color component at each pixel, some of the G and B brightness values reached the maximum value of 8-bit binary number, i.e. 255, above about 2-3 MW. Therefore, we corrected the G and B brightness values by the R signals whose brightness value did not saturate even at 5 MW, the maximum reactor power of KUR. Then, the total brightness value was in proportion to the reactor power after the correction. These results indicate the reactor power can be estimated by the observation of Cherenkov light.
Takahashi, Nobuaki*; Murata, Hirohiko*; Mitsubori, Hitoshi*; Sakuraba, Junji*; Soga, Tomohiro*; Aoki, Yasushi*; Kato, Takanori*; Saito, Yuichi; Yamada, Keisuke; Ikenaga, Noriaki*; et al.
Review of Scientific Instruments, 85(2), p.02C306_1 - 02C306_3, 2014/02
Times Cited Count：2 Percentile：11.64(Instruments & Instrumentation)Sasaki, Takuo; Norman, A. G.*; Romero, M. J.*; Al-Jassim, M. M.*; Takahashi, Masamitsu; Kojima, Nobuaki*; Oshita, Yoshio*; Yamaguchi, Masafumi*
Physica Status Solidi (C), 10(11), p.1640 - 1643, 2013/11
Times Cited Count：4 Percentile：84.06Nishi, Toshiaki*; Sasaki, Takuo; Ikeda, Kazuma*; Suzuki, Hidetoshi*; Takahashi, Masamitsu; Shimomura, Kenichi*; Kojima, Nobuaki*; Oshita, Yoshio*; Yamaguchi, Masafumi*
AIP Conference Proceedings 1556, p.14 - 17, 2013/09
Times Cited Count：0 Percentile：0.01Arai, Masatoshi; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Nakajima, Kenji; Shibata, Kaoru; Takahashi, Nobuaki; Suzuki, Junichi*; Takata, Shinichi; Yamada, Takeshi*; et al.
Journal of the Physical Society of Japan, 82(Suppl.A), p.SA024_1 - SA024_14, 2013/01
Times Cited Count：7 Percentile：48.23(Physics, Multidisciplinary)The paper describes developments of neutron scattering instruments in J-PARC neutron facility, which is a short pulse spallation source operated at a repetition rate 25 Hz and has a proton power 1 MW. New concept has been adopted to utilize high intensity coupled moderator even for a high resolution inelastic scattering instruments by taking a pulse shaping chopper system. Advanced technique has been also realized by taking an ability of event-recording system altogether with an improvement of a chopper system, realizing multi-Ei method. The paper also touches upon a general design concept for diffractometers in accordance with the source characteristics.
Kanaya, Toshiji*; Takahashi, Nobuaki; Takeshita, Hiroki*; Okura, Masatoshi*; Nishida, Koji*; Kaji, Keisuke*
Polymer Journal, 44(1), p.83 - 94, 2012/01
Times Cited Count：25 Percentile：65.5(Polymer Science)
at the MLF, J-PARCTakahashi, Nobuaki; Shibata, Kaoru; Kawakita, Yukinobu; Nakajima, Kenji; Inamura, Yasuhiro; Nakatani, Takeshi; Nakagawa, Hiroshi; Fujiwara, Satoru; Sato, Taku*; Tsukushi, Itaru*; et al.
Journal of the Physical Society of Japan, 80(Suppl.B), p.SB007_1 - SB007_4, 2011/12
Times Cited Count：6 Percentile：43.95(Physics, Multidisciplinary)Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Nakamura, Mitsutaka; Kajimoto, Ryoichi; Inamura, Yasuhiro; Takahashi, Nobuaki; Aizawa, Kazuya; Suzuya, Kentaro; Shibata, Kaoru; et al.
Journal of the Physical Society of Japan, 80(Suppl.B), p.SB028_1 - SB028_6, 2011/05
Times Cited Count：114 Percentile：95.27(Physics, Multidisciplinary)AMATERAS is a cold-neutron disk-chopper spectrometer in MLF, J-PARC. The construction of main part of the spectrometer has been completed in spring of 2009. Soon after that, we have started the commissioning work on AMATERAS. The performance of AMATERAS has been examined by test experiments in the course of commissioning. In parallel to these works, we have started the user program on AMATERAS from December 2009 and we are getting scientific results from our spectrometer. In this presentation, we will report the current status of AMATERAS including the results of performance tests and some of examples of scientific outputs.
Oto, Tsutomu; Kimura, Tadashi; Miyauchi, Masaru; Nemoto, Nobuaki; Tobita, Kenji; Fukasaku, Akitomi; Takahashi, Kunihiro
JAEA-Review 2010-017, 21 Pages, 2010/07
JAEA-Review-2010-017.pdf:7.68MB
An integrity investigation of a Canal Expanded Joint was carried out as one of the integrity investigation of the JMTR reactor building related facilities and components, before the repair or replacement work of the JMTR related facilities that had begun in FY2007. The Canal Expanded Joint will be used for long-term after the JMTR restart. In the integrity investigation, the visual inspection, the performance test (Surface observations, Durometer hardness test) were investigated respectively and the integrity of the Canal Expanded Joint was confirmed. In order to use the Canal Expanded Joint continuously for long-term, it is important for maintaining the integrity of the Canal Expanded Joint by the periodical maintenance and the repairing work including that has been conducted up to now.
Miyauchi, Masaru; Kimura, Tadashi; Oto, Tsutomu; Nemoto, Nobuaki; Tobita, Kenji; Fukasaku, Akitomi; Takahashi, Kunihiro
JAEA-Review 2010-008, 106 Pages, 2010/06
JAEA-Review-2010-008.pdf:8.89MB
An integrity investigation was carried out for the JMTR Concrete Structure (Vent Stack, Trench, Canal Building, Filter Bank), which was the concrete structure and would be used for the long-term after JMTR restart, before the repair or replacement work of the JMTR related facilities that had begun in FY2007. In the integrity investigation, the concrete surface deterioration, the rebound number (nondestructive strength test), compressive strength using drilled concrete core test piece, the static modules of elasticity, the carbonation depth, the reinforced bar corrosion and the chloride ion content were investigated respectively and the integrity of concrete was confirmed. After the investigation, repair works such as re-painting of the Vent Stack and Trench were carried out from the viewpoint of prevention of flaking off, floating of the painting and the thinning due to the investigation results. In order to use the JMTR concrete structure continuously for long-term, it is important for maintaining the integrity of a concrete structure by the periodical maintenance and the repairing work including the building outer-wall surface painting that has been conducted up to now.
Kimura, Tadashi; Oto, Tsutomu; Miyauchi, Masaru; Nemoto, Nobuaki; Tobita, Kenji; Fukasaku, Akitomi; Takahashi, Kunihiro
JAEA-Review 2010-001, 27 Pages, 2010/03
JAEA-Review-2010-001.pdf:18.81MB
In order to investigate an integrity of the UCL (Utility Cooling Line) elevated water tank to be used for a long term after the JMTR restart, investigation on the base of the UCL elevated tank, especially for the part which had a significant aged effect, was carried out before the refurbishment work of the JMTR related facilities which had begun in FY2007. In the integrity investigation, it was confirmed that some part of the base bolts had significant aged effects, there were no evidence of crack and false indication in the welding region though thinning were observed in some parts of the base plate and the surrounding plate. After the investigation, repair works such as re-painting of the UCL elevated water tank were carried out from the viewpoint of prevention of flaking off, floating of the painting and the thinning due to corrosion based on the investigation results. In order to maintain the integrity of the UCL elevated tank, the periodical maintenance and the repair works of the base of the UCL elevated tank are important for continuous use of it in future.
Kimura, Tadashi; Oto, Tsutomu; Miyauchi, Masaru; Nemoto, Nobuaki; Tobita, Kenji; Fukasaku, Akitomi; Takahashi, Kunihiro
JAEA-Review 2009-054, 73 Pages, 2010/03
JAEA-Review-2009-054.pdf:6.79MB
An integrity investigation was carried out for the JMTR reactor building, which was the concrete structure and would be used for the long-term after JMTR restart, before the repair or replacement work of the JMTR related facilities that had begun in FY2007. In the integrity investigation, the concrete surface deterioration, the rebound number (nondestructive strength test), compressive strength using drilled concrete core test piece, the static modules of elasticity, the carbonation depth, the reinforced bar corrosion and the chloride ion content were investigated respectively and the integrity of concrete was confirmed. In order to use the JMTR reactor building continuously for long-term, it is important for maintaining the integrity of a concrete structure by the periodical maintenance and the repairing work including the building outer-wall surface painting that has been conducted up to now.
Ebisawa, Hiroyuki; Hanakawa, Hiroki; Asano, Norikazu; Kusunoki, Hidehiko; Yanai, Tomohiro; Sato, Shinichi; Miyauchi, Masaru; Oto, Tsutomu; Kimura, Tadashi; Kawamata, Takanori; et al.
JAEA-Technology 2009-030, 165 Pages, 2009/07
JAEA-Technology-2009-030.pdf:69.18MB
The condition of facilities and machinery used continuously were investigated before the renewal work of JMTR on FY 2007. The subjects of investigation were reactor building, primary cooling system tanks, secondary cooling system piping and tower, emergency generator and so on. As the result, it was confirmed that some facilities and machinery were necessary to repair and others were used continuously for long term by maintaining on the long-term maintenance plan. JMTR is planed to renew by the result of this investigation.
Arai, Masatoshi; Aizawa, Kazuya; Nakajima, Kenji; Shibata, Kaoru; Takahashi, Nobuaki
JAEA-Review 2009-014, 84 Pages, 2009/07
JAEA-Review-2009-014.pdf:25.2MB
The 2nd International Advisory Committee on "Biomolecular Dynamics Backscattering Spectrometer DNA" was held on November 12th - 13th, 2008 at J-PARC Center, Japan Atomic Energy Agency. This IAC has been organized for aiming to realize an innovative neutron backscattering instrument in the Materials and Life Science Facility (MLF) at the J-PARC and therefore four leading scientists in the field of neutron backscattering instruments has been selected as the member (Dr. Dan Neumann (Chair), Prof. Ferenc Mezei, Dr. Hannu Mutka, Dr. Philip Tregenna-Piggott), and the 1st IAC had been held on February 27th - 29th, 2008. This report includes the executive summary and materials of the presentations in the 2nd IAC.
Kubo, Junichi*; Rahman, N.*; Takahashi, Nobuaki; Kawai, Takahiko*; Matsuba, Go*; Nishida, Koji*; Kanaya, Toshiji*; Yamamoto, Masahide*
Journal of Applied Polymer Science, 112(3), p.1647 - 1652, 2009/05
Times Cited Count：24 Percentile：61.82(Polymer Science)Aiming at improvement of mechanical and dielectric properties of poly(vinyl alcohol) (PVA) we prepared composites of PVA and magnesium nitrate. It was found that the composites were very soft and rubber-like, and the glass transition temperature decreased with increasing the salt concentration. Wide-angle X-ray diffraction and small-angle X-ray scattering revealed that the crystallites of PVA were destroyed by the additive and it was a cause of the softening.
Takahashi, Nobuaki; Shibata, Kaoru; Sato, Taku*; Kawakita, Yukinobu*; Tsukushi, Itaru*; Metoki, Naoto; Nakajima, Kenji; Arai, Masatoshi
Nuclear Instruments and Methods in Physics Research A, 600(1), p.91 - 93, 2009/02
Times Cited Count：8 Percentile：51.06(Instruments & Instrumentation)A time-of-flight crystal-analyzer neutron inelastic scattering spectrometer DNA has been proposed to construct in the MLF of J-PARC. DNA has been designed to have three crystal analyzers, PG(002), Ge(311) and Si(111) at near-backscattering configurations to study dynamics of biomolecules and proteins in wide energy and momentum transfer ranges. In order to develop the Ge(311) analyzer-crystals we have performed neutron beam experiments to check rocking curves on two candidates, i.e., (a) thick hot-pressed wafers and (b) stacked number of thin as-cut wafers, at the MUSASI port, which is a triple-axis instrument, located on the T2 beam line at the JRR-3M guide hall, Tokai, Japan.
Takahashi, Nobuaki
Hamon, 19(1), p.14 - 17, 2009/01
Arai, Masatoshi; Aizawa, Kazuya; Nakajima, Kenji; Shibata, Kaoru; Takahashi, Nobuaki
JAEA-Review 2008-036, 162 Pages, 2008/08
JAEA-Review-2008-036.pdf:38.32MB
A workshop entitled "Biomolecular Dynamics Backscattering Spectrometers" was held on February 27th - 29th, 2008 at J-PARC Center, Japan Atomic Energy Agency. This workshop was planned to be held for aiming to realize an innovative neutron backscattering instrument, namely DNA, in the MLF and thus four leading scientists in the field of neutron backscattering instruments were invited as the International Advisory Committee (IAC member: Dr. Dan Neumann (Chair); Prof. Ferenc Mezei, Dr. Hannu Mutka; Dr. Philip Tregenna-Piggott) for DNA from institutes in the United States, France and Switzerland, where backscattering instruments are in-service. It was therefore held in the form of lecture anterior and then in the form of the committee posterior. This report includes the executive summary of the IAC and materials of the presentations in the IAC and the workshop.
Takahashi, Nobuaki; Shibata, Kaoru; Sato, Taku*; Arai, Masatoshi; Mezei, F.*
Nuclear Instruments and Methods in Physics Research A, 587(2-3), p.350 - 362, 2008/03
Times Cited Count：2 Percentile：22.48(Instruments & Instrumentation)We have developed a novel configuration concept of crystal-chips for a time-of-flight (TOF) crystal-analyzer neutron inelastic scattering spectrometer, which simultaneously achieves time-focusing, spatial-focusing and momentum-correcting abilities. This concept will be adopted to a coming TOF near-backscattering spectrometer, DIANA which has been proposed to construct at Japan Proton Accelerator Research Complex (J-PARC). At first, layout method satisfying both of the time- and spatial-focusing concepts and momentum-correction concept have been introduced briefly, and then, the focusing performances have been evaluated by Monte-Carlo simulations. Simulations have been performed on a generally-used energy-focusing analyzer as a comparison.
