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JAEA Reports

Measurement of high-energy neutron fluxes and spectra around the J-PARC mercury spallation neutron target using multi-foil activation method

Kasugai, Yoshimi; Harada, Masahide; Kai, Tetsuya; Oi, Motoki; Meigo, Shinichiro; Maekawa, Fujio

JAEA-Data/Code 2015-033, 28 Pages, 2016/03

JAEA-Data-Code-2015-033.pdf:1.78MB

The high-energy neutron fluxes and spectra around the mercury spallation neutron source at MLF of J-PARC were measured by the multi-foil activation method. The threshold energies of neutron reactions utilized in this experiment covered from 0.1 to 50 MeV. The foil irradiation was carried out on the first beam-run of MLF from May 30th to 31th, 2008. After the irradiation, the induced radioactivity of each foil was measured using an HPGe detector, and the neutron-induced reaction-rate distribution around the mercury target was determined. Using these data, the high-energy neutron fluxes and spectra were deduced with unfolding method in which the neutron spectra calculated with PHITS code were used as the initial-guess spectra. By comparison between the initial and the unfolded spectra, it was shown that most of the calculation results, which had been the basis of the neutronics design of the MLF target assembly, were consistent with the experimental data within $$pm$$30%.

Journal Articles

Nuclear technology and potential ripple effect of superconducting magnets for fusion power plant

Nishimura, Arata*; Muroga, Takeo*; Takeuchi, Takao*; Nishitani, Takeo; Morioka, Atsuhiko

Fusion Engineering and Design, 81(8-14), p.1675 - 1681, 2006/02

 Times Cited Count:3 Percentile:25.6(Nuclear Science & Technology)

In a fusion reactor plant, a neutral beam injector (NBI) will be operated for a long time, and it will allow neutron streaming from NBI ports to outside of the plasma vacuum vessel. It requires the superconducting magnet to develop nuclear technology to produce stable magnetic field and to reduce activation of the magnet components. In this report, the back ground of the necessity and the contents of the nuclear technology of the superconducting magnets for fusion application are discussed and some typical investigation results are presented, which are the neutron irradiation effect on Nb$$_{3}$$Sn wire, the development of low activation superconducting wire, and the design concept to reduce nuclear heating and nuclear transformation by streaming. In addition, recent activities in high energy particle physics are introduced and potential ripple effect of the technology of the superconducting magnets is described briefly.

Journal Articles

Residual stress measurement technique using X-ray and neutron diffraction methods

Suzuki, Hiroshi

Netsu Shori, 46(1), p.11 - 18, 2006/02

no abstracts in English

Journal Articles

Characterization of radionuclides formed by high-energy neutron irradiation

Yokoyama, Sumi; Sato, Kaoru; Noguchi, Hiroshi; Tanaka, Susumu; Iida, Takao*; Furuichi, Shinya*; Kanda, Yukio*; Oki, Yuichi*; Kaneto, Taihei*

Radiation Protection Dosimetry, 116(1-4), p.401 - 405, 2005/12

 Times Cited Count:1 Percentile:11.17(Environmental Sciences)

The physicochemical property of radionuclides suspended in the air is an important parameter to evaluate internal doses due to the inhalation of the airborne radionuclides and to develop the air monitoring system in high-energy proton accelerator facilities. This study focuses on the property of radioactive airborne chlorine ($$^{38}$$Cl and $$^{39}$$Cl) and sulfur ($$^{38}$$S) formed from Ar gas by irradiation with high-energy neutrons. As a result of the irradiation to a mixture of Ar gas and dry air, $$^{38}$$Cl and $$^{39}$$Cl existed as non-acidic gas and $$^{38}$$S was present as acidic gas. Further, it was found that in the high-energy neutron irradiation to aerosol containing-Ar gas, the higher the amount of radioactive aerosols becomes, the lower that of radioactive acidic gas becomes.

Journal Articles

Development of dose monitoring system applicable to various radiations with wide energy ranges

Sato, Tatsuhiko; Satoh, Daiki; Endo, Akira; Yamaguchi, Yasuhiro

Journal of Nuclear Science and Technology, 42(9), p.768 - 778, 2005/09

 Times Cited Count:16 Percentile:74.09(Nuclear Science & Technology)

A new inventive radiation monitor, designated to DARWIN (Dose Assessment system applicable to various Radiations with WIde energy raNges), has been developed for monitoring doses at workspaces of high energy accelerator facilities and on ground. Characteristics of DARWIN were studied by both calculation and experiment. The calculated results indicate that DARWIN gives reasonable estimations of doses at most radiation fields. It was found from the experiment that DARWIN has an excellent property of measuring doses from all particles that significantly contribute to the background dose - photon, muon and neutron with wide energy ranges.

Journal Articles

Development of neutron-monitor detector using liquid organic scintillator coupled with $$^{6}$$Li+ZnS(Ag) sheet

Sato, Tatsuhiko; Endo, Akira; Yamaguchi, Yasuhiro; Takahashi, Fumiaki

Radiation Protection Dosimetry, 110(1-4), p.255 - 261, 2004/09

 Times Cited Count:8 Percentile:50.96(Environmental Sciences)

For monitoring of neutron doses in high-energy accelerator facilities, we have developed a neutron-monitor detector applicable to energies from the thermal energy to 100 MeV. The detector is composed of a cylindrical (12.7 cm in diameter and 12.7 cm in length) liquid organic scintillator BC501A covered with $$^{6}$$Li+ZnS(Ag) sheets. Characteristics of this phoswitch-type detector were studied experimentally in moderated neutron fields of $$^{241}$$Am-Be and $$^{252}$$Cf sources, and in quasi-monoenergetic neutron fields of 40 and 70 MeV. It was found from the experiments that the detector is enough sensitive to both thermal and fast neutrons, and has an excellent property of pulse-shape discrimination between them. We concluded, therefore, that the detector can be used for monitoring of neutron doses over a wide energy range from the thermal to 100 MeV.

Journal Articles

Development of a high-performance microstrip gas chamber with a capability of track discrimination for neutron detection

Nakamura, Tatsuya; Yamagishi, Hideshi; Masaoka, Sei; Soyama, Kazuhiko; Aizawa, Kazuya

Nuclear Instruments and Methods in Physics Research A, 529(1-3), p.336 - 341, 2004/08

 Times Cited Count:6 Percentile:42.52(Instruments & Instrumentation)

A microstrip gas chamber (MSGC) with a capability of track discrimination for neutron detection was developed whilst ensuring the stability of the MSGC and fulfilling the specifications required for detectors using in high-flux reactors and high-intensity pulsed-neutron sources. The developed two-dimensional detector system comprises a MSGC with individual signal channel read-outs and a new instrument system with a capability of secondary-particle discrimination (InSPaD). The InSPaD identifies the particles -proton and triton- created in the nuclear reaction $$^{3}He + n rightarrow p + T$$ by a simple, fast and cost-effective method using the difference in the track length, and it enables a small amount of heavy gas such as $$C_{2}H_{6}$$ with helium-3 to be used as the filling gas whilst achieving a high spatial resolution.

JAEA Reports

Experimental study on accelerator driven subcritical reactor, JAERI's nuclear research promotion program, H12-031 (Contract research)

Shiroya, Seiji*; Misawa, Tsuyoshi*; Unesaki, Hironobu*; Ichihara, Chihiro*; Kobayashi, Keiji*; Nakamura, Hiroshi*; Shin, Kazuo*; Imanishi, Nobutsugu*; Kanazawa, Satoshi*; Mori, Takamasa

JAERI-Tech 2004-025, 93 Pages, 2004/03

JAERI-Tech-2004-025.pdf:6.69MB

In view of the future plan of Research Reactor Institute, Kyoto University, the present study consisted of (1) the transmission experiments of high energy neutrons through materials, (2) experimental simulation of ADSR using the Kyoto University Critical Assembly(KUCA), and (3) conceptual neutronics design study on KUR type ADSR using the MCNP-X code. Through the present study, valuable knowledge on the basic nuclear characteristics of ADSR, which is indispensable to promote the study on ADSR, was obtained both theoretically and experimentally. For the realization of ADSR, it is considered to be necessary to accumulate results of research steadily. For this purpose, it is inevitable (1) to compile the more precise nuclear data for the wide energy range, (2) to establish experimental techniques for reactor physics study on ADSR including subcriticality measurement and absolute neutron flux measurement, and (3) to develop neutronics calculation tools which take into account the neutron generation process by the spallation reaction and the delayed neutron behavior.

Journal Articles

Development of neutron-monitor detectors applicable to energies from thermal to 100MeV

Endo, Akira; Kim, E.; Yamaguchi, Yasuhiro; Sato, Tatsuhiko; Yoshizawa, Michio; Tanaka, Susumu; Nakamura, Takashi; Rasolonjatovo, A. H. D.*

Journal of Nuclear Science and Technology, 41(Suppl.4), p.510 - 513, 2004/03

no abstracts in English

Journal Articles

Glass formation at the limit of insufficient network formers

Kohara, Shinji*; Suzuya, Kentaro; Takeuchi, Ken*; Loong, C.-K.*; Grimsditch, M.*; Weber, J. K. R.*; Tangeman, J. A.*; Key, T. S.*

Science, 303(5664), p.1649 - 1652, 2004/03

 Times Cited Count:126 Percentile:95.14(Multidisciplinary Sciences)

Inorganic glasses normally exhibit a network of interconncted covalent-bonded structural elements that has no long-range order. In silicate glasses the network formers are based on SiO$$_4$$-tetrahedra interconnected via oxygen atoms at the corners. Conventional wisdom then implies that alkaline and alkaline-earth orthosilicate materials cannot be vitrified because they do not contain sufficient network forming SiO$$_2$$ to establish the needed interconnectivity. We have studied a bulk magnesium orthosilicate glass obtained by containerless melting-and-cooling. We find that the role of network former is largely taken on by corner- and edge-sharing of highly distorted ionic Mg-O species that adopt 4-, 5- and 6-coordination with oxygen. The results suggest that similar novel glassy phases may be found in the containerless environment of interstellar space.

JAEA Reports

Measurement of radioactivity induced by GeV-protons and spallation neutrons using AGS accelerator

Kasugai, Yoshimi; Kai, Tetsuya; Maekawa, Fujio; Nakashima, Hiroshi; Takada, Hiroshi; Konno, Chikara; Numajiri, Masaharu*; Ino, Takashi*; Takahashi, Kazutoshi*

JAERI-Research 2003-034, 115 Pages, 2004/01

JAERI-Research-2003-034.pdf:4.18MB

Measurement of radioactivity induced by high-energy protons with energy of 2.83 and 24 GeV and spallation neutrons produced by bombarding a mercury target with the high-energy protons were performed by using the AGS (Alternative Gradient Synchrotron) accelerator at Brookhaven National Laboratory. The samples of boron, carbon, aluminum, iron, copper, niobium, mercury-oxide, lead, bismuth, acrylic resin, SS-316, Inconel-625 and Inconel-718 were irradiated around the mercury target. After the irradiation, the radioactivity of each sample was measured by using HPGe detectors at the cooling time between 2 h and 200 d. In the processing of the measured $$gamma$$-ray spectra, more than 90 radioactive nucleus were identified, and the radioactivity data were obtained. This report gives the experimental procedure, the data processing and the experimental results in detail.

Journal Articles

Radiation control system for J-PARC

Miyamoto, Yukihiro

Hokeikyo Nyusu, (32), p.2 - 3, 2003/10

no abstracts in English

Journal Articles

Study of particle size distribution and formation mechanism of radioactive aerosols generated in high-energy neutron fields

Endo, Akira; Sato, Kaoru; Noguchi, Hiroshi; Tanaka, Susumu; Iida, Takao*; Furuichi, Shinya*; Kanda, Yukio*; Oki, Yuichi*

Journal of Radioanalytical and Nuclear Chemistry, 256(2), p.231 - 237, 2003/05

 Times Cited Count:6 Percentile:43.28(Chemistry, Analytical)

Size distributions of $$^{38}$$Cl, $$^{39}$$Cl, $$^{82}$$Br and $$^{84}$$Br aerosols generated by irradiations of argon and krypton gases containing di-octyl phthalate (DOP) aerosols with 45MeV and 65MeV quasi-monoenergetic neutrons were measured to study the formation mechanism of radioactive particles in high energy radiation fields. Effects of the size distribution of the radioactive aerosols on the size of added DOP aerosols, the energy of irradiation neutrons and the kinds of nuclides were studied. The observed size distributions of the radioactive particles were explained by attachment of the radioactive atoms generated by the neutron-induced reactions to the DOP aerosols.

JAEA Reports

Proceedings of the 3rd Workshop on Dosimetry for External Radiations; November 28-29, 2002, Japan Atomic Energy Research Institute, Tokai, Ibaraki, Japan

Yoshizawa, Michio; Endo, Akira

JAERI-Conf 2003-002, 166 Pages, 2003/03

JAERI-Conf-2003-002.pdf:9.79MB

The present report is Proceedings of the Third Workshop on Dosimetry for External Radiations, held at the Tokai Research Establishment, Japan Atomic Energy Research Institute (JAERI), in November 28-29, 2002. The proceedings comprises 16 papers and a summary of general discussion. The Third Workshop, subtitled "On an opportunity of the completion of the facility of calibration standards for neutron at JAERI", focused on neutron dosimetry and included presentations on the status of international neutron standards, the development of calibration techniques of neutron dosimeters using accelerator neutron sources, and dosimetry for high-energy neutrons. The workshop identified the directions for the future research and development in this field.

Journal Articles

Neutronic optimization of premoderator and reflector for decoupled hydrogen moderator in 1MW spallation neutron source

Harada, Masahide; Teshigawara, Makoto; Kai, Tetsuya; Sakata, Hideaki*; Watanabe, Noboru; Ikeda, Yujiro

Journal of Nuclear Science and Technology, 39(8), p.827 - 837, 2002/08

 Times Cited Count:18 Percentile:74.81(Nuclear Science & Technology)

For a decoupled hydrogen (super critical) moderator, optimization studies have been performed on a premoderator and reflector material (Pb, Be, Fe and Hg) together with the decoupling energy to realize a higher neutronic performance. The result indicated that the best neutronic performance could be obtained for a decoupled H$$_2$$ moderator in a Pb reflector by optimizing the premoderator and adopting an appropriate decoupling energy, even compared with optimized one in a Be reflector.

Journal Articles

Particle size analysis of radioactive aerosols formed by irradiation of argon using 65MeV quasi-monoenergetic neutrons

Endo, Akira; Noguchi, Hiroshi; Tanaka, Susumu; Kanda, Yukio*; Oki, Yuichi*; Iida, Takao*; Sato, Kaoru; Tsuda, Shuichi

Applied Radiation and Isotopes, 56(4), p.615 - 620, 2002/04

 Times Cited Count:3 Percentile:24.34(Chemistry, Inorganic & Nuclear)

Formation mechanism and size distribution of radioactive aerosol particles generated in a high-energy neutron field were studied in order to evaluate a particle size parameter for internal dose evaluation in high-energy accelerator facilities. Argon gas containing DOP aerosols was irradiated by a 65MeV quasi-monoenergetic neutron beam of TIARA. The number size distribution of the DOP aerosols and the activity-weighted size distribution of $$^{38}$$Cl and $$^{39}$$Cl aerosols, formed from the (n, 2np) and (n, np) reactions of $$^{40}$$Ar, were measured using an electrical low-pressure impactor. The activity-weighted size distribution of the radioactive aerosols was well explained by the simple attachment model of the radioactive atoms to the DOP aerosols.

JAEA Reports

Reliability assessment of high energy particle induced radioactivity calculation code DCHAIN-SP 2001 by analysis of integral activation experiments with 14MeV neutrons

Kai, Tetsuya; Maekawa, Fujio; Kasugai, Yoshimi; Kosako, Kazuaki*; Takada, Hiroshi; Ikeda, Yujiro

JAERI-Research 2002-005, 65 Pages, 2002/03

JAERI-Research-2002-005.pdf:2.75MB

Reliability assessment for the High Energy Particle Induced Radioactivity Calculation Code DCHAIN-SP 2001 was carried out through analysis of integral activation experiments with 14-MeV neutrons. The following three series of experiments conducted at the D-T neutron source facility, FNS, in JAERI were employed: (1) the decay gamma-ray measurement experiment for fusion reactor materials, (2) the decay heat measurement experiment for 32 fusion reactor materials, and (3) the integral activation experiment on mercury.As a result, it was found that the calculations with DCHAIN-SP 2001 predicted the experimental data for (1)$$sim$$(3) approximately within 30%, 20% and 20%, respectively. It was concluded that the activation cross section data below 20 MeV and the associated decay data as well as the calculation algorithm for solving the Beteman equation that was the master equation of DCHAIN-SP were adequate.

JAEA Reports

Proceedings of the 3rd Symposium on Science of Hadrons under Extreme Conditions; January 29-31, 2001, JAERI, Tokai, Japan

Chiba, Satoshi

JAERI-Conf 2001-012, 116 Pages, 2001/09

JAERI-Conf-2001-012.pdf:6.33MB

The third symposium on Science of Hadrons under Extreme Conditions, organized by the Research Group for Hadron Science, Advanced Science Research Center, was held at Tokai Research Establishment of JAERI on January 29 to 31, 2001. The symposium was devoted for discussions and presentations of research results in wide variety of hadron physics such as nuclear matter, high-energy nuclear reactions, quantum chromodynamics, neutron stars,supernovae, nucleosynthesis as well as finite nuclei to understand various aspects of hadrons under extreme conditions. Twenty two papers on these topics, including a special talk on the present status of JAERI-KEK joint project on high-intentisy proton accelerator, presented at the symposium aroused lively discussions among approximately 40 participants.

Journal Articles

Improvement of neutron detection efficiency with high sensitive CR-39 track detector

Oda, Keiji*; Ichijo, H.*; Miyawaki, Nobumasa*; Yamauchi, Tomoya*; Nakane, Yoshihiro

Radiation Measurements, 34(1-6), p.171 - 175, 2001/06

 Times Cited Count:7 Percentile:50.11(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Development of Monte Carlo code in JAERI

Mori, Takamasa; Okumura, Keisuke; Nagaya, Yasunobu

Transactions of the American Nuclear Society, 84, p.45 - 46, 2001/06

no abstracts in English

30 (Records 1-20 displayed on this page)