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Yamada, Hirohisa*; Yokoyama, Shingo*; Watanabe, Yujiro*; Suzuki, Masaya*; Suzuki, Shinichi; Hatta, Tamao*
Nihon Ion Kokan Gakkai-Shi, 25(4), p.207 - 211, 2014/11
Maekawa, Fujio; Harada, Masahide; Oikawa, Kenichi; Teshigawara, Makoto; Kai, Tetsuya; Meigo, Shinichiro; Oi, Motoki; Sakamoto, Shinichi; Takada, Hiroshi; Futakawa, Masatoshi; et al.
Nuclear Instruments and Methods in Physics Research A, 620(2-3), p.159 - 165, 2010/08
Times Cited Count：73 Percentile：97.59(Instruments & Instrumentation)The J-PARC 1-MW pulsed spallation neutron source JSNS was successfully launched on 30th of May 2008. To demonstrate the unique features of the moderator design and the neutronic performance of JSNS the neutron spectral intensity, absolute neutron flux, and time structure of the neutron pulse shapes etc have been measured using several neutron instruments since then. The measured energy spectra clearly revealed the feature of the para-hydrogen, as expected when designing the moderator. The measured neutron flux below 0.4 eV agreed with the corresponding design value within 
20%, thus suggesting that the JSNS design calculations to have been reliable. World-class high-resolution diffraction data could be recorded due to the suitability of design of the moderators and the instruments. Another world-class high-intensity neutron flux was also capable of being demonstrated due to the unique design of the large cylindrical coupled moderator.
Maekawa, Fujio; Oikawa, Kenichi; Harada, Masahide; Kai, Tetsuya; Meigo, Shinichiro; Kasugai, Yoshimi; Oi, Motoki; Sakai, Kenji; Teshigawara, Makoto; Hasegawa, Shoichi; et al.
Nuclear Instruments and Methods in Physics Research A, 600(1), p.335 - 337, 2009/02
Times Cited Count：42 Percentile：92.89(Instruments & Instrumentation)A neutron beam line (BL10) of JSNS, NOBORU, has been constructed in the Materials and Life Science Experimental Facility (MLF) at J-PARC. A primal mission of NOBORU is to study neutronic performance of JSNS. We will measure the memorable first neutron pulse of JSNS at the Day-one by using NOBORU, and then measure neutron pulse shape, spectrum, intensity distribution, etc. for facility diagnostics. Since NOBORU also has an aspect as a test port, it welcomes trial uses to develop innovative instruments. Trial experiments to demonstrate several innovative instruments at NOBORU are under planning.
Oikawa, Kenichi; Maekawa, Fujio; Harada, Masahide; Kai, Tetsuya; Meigo, Shinichiro; Kasugai, Yoshimi; Oi, Motoki; Sakai, Kenji; Teshigawara, Makoto; Hasegawa, Shoichi; et al.
Nuclear Instruments and Methods in Physics Research A, 589(2), p.310 - 317, 2008/05
Times Cited Count：54 Percentile：95.02(Instruments & Instrumentation)NOBORU, NeutrOn Beam-line for Observation and Research Use, has been constructed in the Materials and Life Science Facility (MLF) of J-PARC. NOBORU is designed to "Observe" a 1 MW Japan Spallation Neutron Source (JSNS), i.e., to study the neutronic performance of JSNS. NOBORU also will be used for "Research" activities, i.e., as a test port for R&D activities and trial users who have new ideas. In this paper, the design and application of NOBORU are described, and its expected performance is investigated by Monte Carlo simulations.
Harada, Masahide; Watanabe, Noboru*; Teshigawara, Makoto; Kai, Tetsuya; Kato, Takashi; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research A, 574(3), p.407 - 419, 2007/05
Times Cited Count：14 Percentile：68.37(Instruments & Instrumentation)Neutronic performance of a poisoned hydrogen moderator was studied in details. Using a simple rectangular-shape moderator-model, its basic characteristics were studied as a function of the poison position. We, for the first time, turned up that the pulse width was rather decreasing with increasing the moderator thickness of the back part from the poison. This is due to the fact that source neutron pulses entering through the back part of poison are narrow while those from the target and the reflector through the decoupler and liner are broad. Next, we studied the pulse deterioration in regard to a finite beam-extraction-angle by using a canteen shape and a concave shape. It turns out that the pulse deterioration is large in both cases even at a small extraction angle. The concave-shape moderator indicates a finite improvement compared to the canteen shape one. Finally, merits and demerits of two poison materials, Cd and Gd, were discussed considering the burn-up issue of poison.
in JSNSMaekawa, Fujio; Oikawa, Kenichi; Harada, Masahide; Kai, Tetsuya; Meigo, Shinichiro; Kasugai, Yoshimi; Oi, Motoki; Sakai, Kenji; Teshigawara, Makoto; Hasegawa, Shoichi; et al.
Proceedings of 18th Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-18) (CD-ROM), p.118 - 126, 2007/00
One of 23 neutron beam lines of JSNS, NOBORU, has been assigned to the Neutron Facility Group of JAEA. The primary mission of NOBORU is to investigate neutronic performance of JSNS while it can accommodate various trial research experiments. This paper describes an experimental program by using NOBORU mostly in an on-beam commissioning period of JSNS after the first proton beam acceptance in 2008. Topics for the primary mission to be studied are as follows; relationships between operating parameters of JSNS and neutronic performance, acquisition of beam parameters for users, confirmation of integrity in main components of JSNS, validation of neutronic designs, and research and development on measuring techniques. In addition, we are interested in radiography, introduction of a high-pressure instrument and eV neutron spectroscopy, and also welcome trial uses to bring out new research activities.
Harada, Masahide; Maekawa, Fujio; Teshigawara, Makoto; Watanabe, Noboru*; Kato, Takashi; Ikeda, Yujiro
Proceedings of 18th Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-18) (CD-ROM), p.616 - 626, 2007/00
no abstracts in English
Maekawa, Fujio; Oikawa, Kenichi; Tamura, Masaya; Harada, Masahide; Ikeda, Yujiro; Watanabe, Noboru
LA-UR-06-3904, Vol.1, p.129 - 138, 2006/06
Total 23 neutron beam-lines will be installed for JSNS in the J-PARC project. One of them is assigned for the Materials and Life Science Facility (MLF), and the MLF will construct a neutron beam-line to demonstrate and monitor neutronic performance of JSNS. The neutron beam-line was accordingly named as "Neutron Beam-line for Obserbation and Research Use (NOBORU)". Major parts of the NOBORU, i.e., beam ducts, shield, a beam stop, slits, a cabin for measurement, a pillar crane, a sample table, etc., have been ordered in March 2004, and installation will be completed in 2007. A T0 chopper, a frame-overlap chopper, detector systems, samples, etc. will be ordered later on. The sample position is at 14 m from the decoupled moderator. Approximate sample room dimensions are 3 
2.5 m in area and 3 m in height. A shield structure was determined by shielding calculations in which detailed 3-D structure was considered. The design of NOBORU will be presented in the session.
Harada, Masahide; Watanabe, Noboru; Teshigawara, Makoto; Kai, Tetsuya; Maekawa, Fujio; Kato, Takashi; Ikeda, Yujiro
LA-UR-06-3904, Vol.2, p.700 - 709, 2006/06
Pulse characteristics data for every neutron beam line are indispensable in designing devices for neutron scattering experiments of JSNS. A detailed model was built and pulse characteristics of each beam line were estimated using the PHITS code and the MCNP-4C code. These results have been disclosed on the J-PARC homepage since September 2004. Due to changes of moderator shapes in a progress of manufacture design, we observed from the calculation that pulse structures of decoupled moderators were deteriorated, especially, those of pulse tail. We found that this deterioration was caused by leakage neutron from gaps between decouplers and absorbing liners of the reflector. For a final stage of the manufacture design, we carefully tried to find other factors which deteriorated the pulse characteristics. Furthermore, pulse structures of poisoned and unpoisoned decoupled moderators were evaluated with the consideration of heterogeneous burn-up and leakage neutron spectra including high-energy region up to GeV were estimated for each neutron beam hole.
Kai, Tetsuya; Harada, Masahide; Teshigawara, Makoto; Watanabe, Noboru; Kiyanagi, Yoshiaki*; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research A, 550(1-2), p.329 - 342, 2005/09
Times Cited Count：18 Percentile：74.92(Instruments & Instrumentation)Neutronic study was performed on coupled hydrogen moderators to maximize time-integrated and pulse-peak intensities of slow neutrons when a large number of beams was required. The total increased with the number of beams, although the average decreased due to a reflector-missing by the beam extraction holes in the reflector. At a large beam extraction angle (25 degree), the spatial distribution of the vector-flux of neutrons was undesirable for a rectangular shape moderator. As an alternative we proposed a cylindrical shape one, resulting in a much improved spatial distribution. In addition, neutronic performance was calculated as a function of the diameter, indicating the optimal diameter was about 140 mm. The cylindrical one gave higher pulse-peak intensities with narrower pulse widths without penalty in time-integrated intensities and pulse decay characteristics, providing a more uniform angle-dependence. Some explanations are given for the difference in the pulse characteristics between the two. We decided to adopt the cylindrical one for the Japanese spallation neutron source.
Harada, Masahide; Watanabe, Noboru; Konno, Chikara; Meigo, Shinichiro; Ikeda, Yujiro; Niita, Koji*
Journal of Nuclear Materials, 343(1-3), p.197 - 204, 2005/06
Times Cited Count：31 Percentile：87.1(Materials Science, Multidisciplinary)For a construction of maintenance and storage scenarios for JSNS, lives of structure material need to be estimated. DPA (Displacement per Atom) was a major index of radiation damage. So we evaluated DPA value of each component. Function of the DPA calculation was equipped to the PHITS code, which was particle and heavy ion transport code. For DPA calculation, displacement cross section was necessary. Displacement cross sections of neutron below 150 MeV were processed by the NJOY code from LA150 library and those of neutron above 150MeV and proton in the all energy region were obtained from energies of fragments calculated in the PHITS. By using the PHITS, we calculated DPA values and DPA mapping. We obtained that the peak DPA values at end of 5000MWh operation were 4.1 for target vessel, 2.8 for reflector and moderator vessels, and 0.4 for proton beam windows, respectively. We estimated the target life at 1 year and the moderator life at 6 year.
Maekawa, Fujio; Meigo, Shinichiro; Kasugai, Yoshimi; Takada, Hiroshi; Ino, Takashi*; Sato, Setsuo*; Jerde, E.*; Glasgow, D.*; Niita, Koji*; Nakashima, Hiroshi; et al.
Nuclear Science and Engineering, 150(1), p.99 - 108, 2005/05
Times Cited Count：6 Percentile：40.47(Nuclear Science & Technology)A neutronic benchmark experiment on a simulated spallation neutron target assembly with 1.94, 12 and 24 GeV proton beams conducted by using the AGS accelerator at BNL/US was analyzed to investigate validity of neutronics calculations on proton accelerator driven spallation neutron sources. Monte Carlo particle transport calculation codes NMTC/JAM, MCNPX and MCNP-4A with associated cross section data in JENDL and LA-150 were used for the analysis. As a result, although the overall energy range was encompassed from GeV to meV, i.e., more than 12 orders of magnitude, calculated fast and thermal neutron fluxes agreed approximately within 40 % with the experiments. Accordingly, it was concluded that neutronics calculations with these codes and cross section data were adequate for estimating nuclear properties in spallation neutron sources.
Harada, Masahide; Watanabe, Noboru; Teshigawara, Makoto; Kai, Tetsuya; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research A, 539(1-2), p.345 - 362, 2005/02
Times Cited Count：21 Percentile：77.57(Instruments & Instrumentation)Neutronic studies of decoupled hydrogen moderators were performed by calculations taking into account para hydrogen content, decoupling energy, moderator dimensions/shapes and reflector material. Low-energy parts of calculated spectral intensities with different para hydrogen contents were analyzed by a modified Maxwell function to characterize neutron spectra. The result shows that a 100% para hydrogen moderator gives the highest pulse peak intensity together with the narrowest pulse width and the shortest decay times. Pulse broadening with a reflector was explained by time distributions of source neutrons entering into the moderator through a decoupler. Material dependence of time distribution was studied. A decoupling energy higher than 1 eV does not bring about a large improvement in pulse widths and decay times, even at a large penalty in the peak intensity. The optimal moderator thickness was also discussed for a rectangular parallelepiped shape and a canteen shape moderators.
Kai, Tetsuya; Harada, Masahide; Teshigawara, Makoto; Watanabe, Noboru; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research A, 523(3), p.398 - 414, 2004/05
Times Cited Count：36 Percentile：89.22(Instruments & Instrumentation)Neutronic performance of a coupled hydrogen moderator was studied as a function of para hydrogen concentration, moderator thickness, height and premoderator thickness. It was found that a thick (120
140mm) moderator with 100% para hydrogen was optimal to provide the highest time- and energy- integrated neutron intensity below 15 meV together with the highetst possible pulse-peak intensity. Low-energy neutron distribution on the moderator viewed surface was found to exhibit an intensity-enhanced region at a picture frame part near premoderator. The rather peculiar distribution suggested that the moderator and the viewed surface must be designed so as to take the brighter region near premoderator in use.
Kiyanagi, Yoshiaki*; Nagamiya, Shoji*; Oyama, Yukio; Ikeda, Yujiro; Oigawa, Hiroyuki; Igashira, Masayuki*; Baba, Mamoru*; Iwasaki, Tomohiko*; Watanabe, Yukinobu*; Ishibashi, Kenji*
Nihon Genshiryoku Gakkai-Shi, 46(3), p.173 - 197, 2004/03
no abstracts in English
Nakashima, Hiroshi; Takada, Hiroshi; Kasugai, Yoshimi; Meigo, Shinichiro; Maekawa, Fujio; Kai, Tetsuya; Konno, Chikara; Ikeda, Yujiro; Oyama, Yukio; Watanabe, Noboru; et al.
Proceedings of 6th Meeting of the Task Force on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF-6), (OECD/NEA No.3828), p.27 - 36, 2004/00
no abstracts in English
Harada, Masahide; Teshigawara, Makoto; Watanabe, Noboru; Kai, Tetsuya; Ikeda, Yujiro
Proceedings of ICANS-XVI, Volume 2, p.697 - 706, 2003/07
For two decoupled moderators in JSNS, optimization studies were performed by model calculations using NMTC/JAM and MCNP-4C codes. The model was based on a realistic Target-Moderator-Reflector Assembly. We assumed a para-hydrogen ratio of 100%. The shape of poisoned and unpoisoned moderators is a canteen type with dimensions of 13
12
6.2
cm
. A decoupling energy of about 1 eV was adopted to meet the user's requests. As a decoupler material we selected silver-indium-cadmium alloy. It was found that for the decoupled moderators, especially the poisoned moderator, pulse broadening due to a finite beam-extraction angle (
) was very serious. Therefore, for the poisoned and the unpoisoned moderators were limited to be 7.5
and 17.5, respectively. Cadmium (Cd) was selected as a poison material due to higher cut-off energy than gadolinium and higher peak intensity with narrower pulse width. The poison plate will be placed at 25 mm from the viewed surface which meets the user's requirements.
Harada, Masahide; Saito, Shigeru; Teshigawara, Makoto; Kawai, Masayoshi*; Kikuchi, Kenji; Watanabe, Noboru; Ikeda, Yujiro
Proceedings of ICANS-XVI, Volume 2, p.677 - 687, 2003/07
As a decoupler material for intense neutron sources, we proposed a new composite material based on the (n,
) reaction, silver-indium-cadmium alloy (AIC), which had lettle helium gas production rate and higher decoupling energy (1eV). We compared an AIC decoupler with Cd and B
C decouplers from various viewpoints and finally selected AIC as decoupler and liner materials. In the current design, we adopted AIC of 2.5mm thick with a composition of Ag-35wt%Cd and 0.5mm thick with Ag-15wt%In. A decoupler and a liner can be bonded to structural material (Al-alloy) by HIP for water cooling through Al-alloy. To find the optimal HIP condition, small pieces of Ag-Cd and Ag-In (
202mm) were enclosed in Al-alloy capsules (22mm, 3mm thick bottom plate and 1mm thick cap) of several Al-alloys. The optimal condition was found to be 500C with a holding time of 60 minutes under a fixed pressure of 100MPa. Large pieces (Ag-Cd: 2002002.5mm, Ag-In: 2002000.5mm, A5083 and A6061: 21021021mm) were also tested aiming at more realistic size conditions.
Takada, Hiroshi; Maekawa, Fujio; Honmura, Shiro*; Yoshida, Katsuhiko*; Teraoku, Takuji*; Meigo, Shinichiro; Sakai, Akio*; Kasugai, Yoshimi; Kanechika, Shuji*; Otake, Hidenori*; et al.
Proceedings of ICANS-XVI, Volume 3, p.1115 - 1125, 2003/07
no abstracts in English
Kai, Tetsuya; Harada, Masahide; Teshigawara, Makoto; Watanabe, Noboru; Ikeda, Yujiro
Proceedings of ICANS-XVI, Volume 3, p.657 - 666, 2003/07
Neutronic design studies were carried out on the J-PARC coupled H
moderator. The highest time- and energy- integrated intensity below 15 meV, pulse peak intensity at 2 meV and 10 meV, were given by 100% para-H moderators, but the optimal moderator thickness was different for each: more than 220 mm, about 120 mm and 80 mm, respectively. Finally, we concluded 140 mm was the optimal thickness for the 100% para-H coupled moderator. Cold neutron distributions on the moderator viewed surface were found to exhibit an intensity-enhanced region at a picture frame part near premoderator. This rather peculiar distribution suggested that the moderator and the viewed surface must be designed so as to take the brighter region near premoderator in use. The intensity decreases along with beam-extraction angle to the normal direction down to about 70% at 25.4
. Then, we propose a cylindrical shape coupled moderator which brings about a slight intensity decrease for 0 but a increase in the averaged intensity over the angles of interest.
