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Journal Articles

Detecting halfmetallic electronic structures of spintronic materials in a magnetic field

Fujiwara, Hidenori*; Umetsu, Rie*; Kuroda, Fumiaki*; Miyawaki, Jun*; Kashiuchi, Toshiyuki*; Nishimoto, Kohei*; Nagai, Kodai*; Sekiyama, Akira*; Irizawa, Akinori*; Takeda, Yukiharu; et al.

Scientific Reports (Internet), 11(1), p.18654_1 - 18654_9, 2021/09

 Times Cited Count:0 Percentile:0(Multidisciplinary Sciences)

JAEA Reports

Risk communication activity which used "YUME Chisoukan" in the Horonobe Underground Research Center; 2015

Fujiwara, Toshiyuki; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*

JAEA-Review 2017-008, 128 Pages, 2017/07

JAEA-Review-2017-008.pdf:8.28MB

Horonobe Underground Research Center managed by Japan Atomic Energy Agency (JAEA) is the Japan's best environment to understand the project of geological disposal of high-level radioactive waste, because there is an Underground Research Laboratory (URL) in the center besides an exhibition facility which explains the content of research conducted in the URL. In the area of the center, there is also an exhibition facility for the full-scale model of engineered barrier system of geological disposal. JAEA takes advantage of this opportunity to conduct public hearing including questionnaire research regarding the questions, anxieties and comments by the visitors for geological disposal project. This report summarizes the result of statistical analysis of 2,674 visitors from April to November in 2015.

Journal Articles

Spatial anisotropy of neutrons emitted from the $$^{56}$$Fe($$gamma$$, n)$$^{55}$$Fe reaction with a linearly polarized $$gamma$$-ray beam

Hayakawa, Takehito; Shizuma, Toshiyuki; Miyamoto, Shuji*; Amano, Sho*; Takemoto, Akinori*; Yamaguchi, Masashi*; Horikawa, Ken*; Akimune, Hidetoshi*; Chiba, Satoshi*; Ogata, Kazuyuki*; et al.

Physical Review C, 93(4), p.044313_1 - 044313_4, 2016/04

 Times Cited Count:7 Percentile:49.44(Physics, Nuclear)

We have measured the azimuthal anisotropy of neutrons emitted from the $$^{56}$$Fe($$gamma$$, n)$$^{55}$$Fe reaction with a linearly polarized $$gamma$$ ray beam generated by laser Compton scattering at NewSUBARU. Neutron yields at the polar angle of 90$$^{circ}$$ have been measured as a function of the azimuthal angle $$phi$$ between the detector and the linear polarization plane of the ray beam. The azimuthal anisotropy of neutrons measured at seven angles has been well reproduced using a theoretically predicted function of $$a$$ + $$b$$cos(2$$phi$$).

JAEA Reports

Risk communication activity which used "YUME Chisoukan" in the Horonobe Underground Research Center; FY2014

Fujiwara, Toshiyuki; Katada, Inao; Hoshino, Masato; Tokunaga, Hiroaki*; Horikoshi, Hidehiko*

JAEA-Review 2015-035, 103 Pages, 2016/03

JAEA-Review-2015-035.pdf:5.65MB

Horonobe Underground Research Center managed by Japan Atomic Energy Agency (JAEA) is the Japan's best environment to understand the project of geological disposal of high-level radioactive waste of Japan because there is an underground research laboratory (URL) in the center besides an exhibition facility which explains the content of research conducted in the URL. In the area of the center, there is also an exhibition facility for the full-scale model of engineered barrier system of geological disposal. JAEA takes advantage of this opportunity to conduct public hearing including questionnaire research regarding the questions, anxieties and comments by the visitors for geological disposal project. This report summarizes the result of statistical analysis of 2457 comments by the visitors from April to November in 2014.

Journal Articles

A Technique for determining the deuterium/hydrogen contrast map in neutron macromolecular crystallography

Chatake, Toshiyuki*; Fujiwara, Satoru

Acta Crystallographica Section D; Structural Biology (Internet), 72(1), p.71 - 82, 2016/01

 Times Cited Count:5 Percentile:38.14(Biochemical Research Methods)

Journal Articles

Diffraction of $$gamma$$-rays with energies of 1.17 and 1.33 MeV by a flat Si crystal

Matsuba, Shunya*; Hayakawa, Takehito; Shizuma, Toshiyuki; Nishimori, Nobuyuki; Nagai, Ryoji; Sawamura, Masaru; Angell, C.; Fujiwara, Mamoru; Hajima, Ryoichi

Japanese Journal of Applied Physics, 54(5), p.052203_1 - 052203_5, 2015/05

 Times Cited Count:3 Percentile:13.97(Physics, Applied)

Journal Articles

Proposal for an advanced hybrid K-edge/XRF densitometry (HKED) using a monochromatic photon beam from laser Compton scattering

Shizuma, Toshiyuki; Hajima, Ryoichi; Hayakawa, Takehito; Fujiwara, Mamoru; Sonoda, Takashi; Seya, Michio

Nuclear Instruments and Methods in Physics Research A, 654(1), p.597 - 603, 2011/10

 Times Cited Count:4 Percentile:32.85(Instruments & Instrumentation)

The general purpose Monte Carlo electron-$$gamma$$ shower computer code (EGS5) was used to obtain the U, Np, and Pu X-ray response from the hybrid K-edge/XRF densitometry (HKED). In the present simulation, we adopt a monochromatic, linearly polarized photon beam generated by inverse Compton scattering of laser light with high energy electrons from an energy recovery linac. The simulation has been carried out under various conditions of the U, Np, and Pu concentrations to investigate the effect to counting rates as well as counting precision. The results of the simulation show that the assessment time for low concentration Pu input solutions can be reduced by the improvement of signal-to-background ratios. The Np concentration can also be determined with a counting precision of approximately 1% in standard deviation during the 1 hour measurement for a 3N HNO$$_3$$ sample solution including U (100 g/L), Np (0.1 g/L), and Pu (20 or 100 g/L).

Journal Articles

Development of a sub-MeV X-ray source via Compton backscattering

Kawase, Keigo; Kando, Masaki; Hayakawa, Takehito; Daito, Izuru; Kondo, Shuji; Homma, Takayuki; Kameshima, Takashi*; Kotaki, Hideyuki; Chen, L. M.*; Fukuda, Yuji; et al.

Nuclear Instruments and Methods in Physics Research A, 637(1, Suppl.), p.S141 - S144, 2011/05

 Times Cited Count:7 Percentile:49.05(Instruments & Instrumentation)

We report the present status of the sub-MeV X-ray generation via Compton backscattering by using 150-MeV electron beam and the Nd:YAG laser. In particular, we show the result of the X-ray generation experiment and of the laser pulse compression for increasing the X-ray flux.

Journal Articles

Status of technology development for the non-destructive assay of Pu in spent fuel using nuclear resonance fluorescence with monochromatic $$gamma$$-rays

Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Nishimori, Nobuyuki; Hayakawa, Takehito; Shizuma, Toshiyuki; Kikuzawa, Nobuhiro; Fujiwara, Mamoru; Seya, Michio

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-31-Kai Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2010/12

We have proposed a nondestructive assay for Pu-239 in spent nuclear fuel assembly under water using nuclear resonance fluorescence with energy tunable monochromatic $$gamma$$-rays generated by Compton scattering of laser photons and high energy electrons. By using $$gamma$$-ray beams of energy of about 2 MeV with good penetrability, one can detect Pu-239 in a spent fuel assembly kept in a water pool from outside the pool wall. In order to realize such $$gamma$$-ray source, we are developing technologies for energy-recovery linac (ERL), which is able to generate small-emittance and high-current electron beams. Here we report development status of an electron gun, superconducting cavity and also we present a design of high-flux $$gamma$$-ray source based on an ERL.

Journal Articles

Nondestructive assay of Pu in spent fuel using nuclear resonance fluorescence with monochromatic $$gamma$$-rays

Hayakawa, Takehito; Shizuma, Toshiyuki; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Fujiwara, Mamoru; Seya, Michio

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-31-Kai Nenji Taikai Rombunshu (CD-ROM), 5 Pages, 2010/12

We have proposed a nondestructive assay for Pu-239 in spent fuel assembly using nuclear resonance fluorescence with energy tunable monochromatic $$gamma$$-rays generated by Compton scattering of laser photons and high energy electrons. This method has advantages that one can detect Pu-239 in a fuel assembly kept in a water pool from outside the pool wall and that one can identify isotopes. We use the $$gamma$$-ray beam with the energy of about 2 MeV and thereby we can detect isotopes though water shields with a thickness of several ten centimeters. We present the concept design of this system, the basic study, and detection accuracy of Pu-239 derived from simulation calculation results using a code GEANT4.

Journal Articles

Applicability of NDA systems using Laser Compton Scattering (LCS) X-rays and $$gamma$$-rays to material accountancy and safeguards verification for future nuclear fuel cycle facilities

Seya, Michio; Hajima, Ryoichi; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Hayakawa, Takehito; Shizuma, Toshiyuki; Fujiwara, Mamoru

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-31-Kai Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2010/12

Energy-recovery linac based laser Compton scattering (LCS) X/$$gamma$$-ray sources have possibilities of various applications to non-destructive assay (NDA) in material accountancy and safeguards verification for future nuclear fuel cycle (FNFC) facilities with advantageous features of very high intensity, monochromaticy and tunability of energy. A LCS-X-ray source with energy of 110-130 keV could be applied to a fast hybrid K-edge densitometer, and a LCS-$$gamma$$-ray source with energy of 1-3 MeV to a NDA system of Pu (and actinide) in spent nuclear fuel and high-level active waste such as hull or vitrified waste by NRF (nuclear resonance fluorescence) method. The LCS-$$gamma$$-ray source with energy of 1-3 MeV could be applied to isotopic analysis of Pu etc. for solution, solid and powder samples after nuclear resonance cross section data of actinides is prepared. Also we present an idea of actual deployment of NDA systems using LCS-X/$$gamma$$-ray sources in a hypothetical FNFC facility.

Journal Articles

Nondestructive assay of plutonium and minor actinide in spent fuel using nuclear resonance fluorescence with laser Compton scattering $$gamma$$-rays

Hayakawa, Takehito; Kikuzawa, Nobuhiro; Hajima, Ryoichi; Shizuma, Toshiyuki; Nishimori, Nobuyuki; Fujiwara, Mamoru; Seya, Michio

Nuclear Instruments and Methods in Physics Research A, 621(1-3), p.695 - 700, 2010/09

 Times Cited Count:42 Percentile:93.11(Instruments & Instrumentation)

We propose a new nondestructive assay method for $$^{235}$$U, $$^{239}$$Pu, and minor actinides in spent nuclear fuel assembly in a water pool. Nuclear fuel materials are detected using nuclear resonance fluorescence (NRF) with laser Compton scattering (LCS) $$gamma$$-rays. The NRF assay can provide a finger print of each isotope since the NRF $$gamma$$-ray energy is characteristic of a specific nuclide. We design a high-flux LCS $$gamma$$-ray source, in which $$gamma$$-rays are generated by collision of laser photons provided from Yb-doped fiber laser and electrons from energy recovery linac. A simulation calculation shows that we can detect 1% fraction $$^{239}$$Pu in all the fuel rods with statistical error lower than 2% using the high flux LCS $$gamma$$-ray source and the measurement time of 4000 s.

Journal Articles

Possible applications of NDA systems using Laser Compton Scattering (LCS) X-rays and $$gamma$$-rays in material accountancy and safeguards verification for future nuclear fuel cycle facilities

Seya, Michio; Hajima, Ryoichi; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Hayakawa, Takehito; Shizuma, Toshiyuki; Fujiwara, Mamoru

Proceedings of INMM 51st Annual Meeting (CD-ROM), 10 Pages, 2010/07

This article introduces possibilities of various applications of ERL (Energy Recovery Linac) based laser Compton scattering (LCS) X- and $$gamma$$-ray sources to nondestructive assay (NDA) in material accountancy and safeguards verification for future nuclear fuel cycle (FNFC) facilities. The NDA system using 1-3 MeV LCS $$gamma$$-ray source (350 MeV electrons + laser) with having semi-monochromatic energy distribution and enough intensity could be applied to measurement of Pu not only in spent nuclear fuel but also in fresh MOX fuel with FPs (fission products) and MAs (minor actinides) by NRF (nuclear resonance fluorescence) method. This NDA system is as well applicable for measuring Pu in hulls or vitrified waste. The NDA system using 100-150 keV LCS X-ray source (85 MeV electrons + laser) could be applied to measurement of concentrations of U, Pu, MAs in solutions with higher speed than the present Hybrid K-edge/XRF densitometer.

Journal Articles

Nondestructive assay of plutonium in spent nuclear fuel assembly in water pool

Hayakawa, Takehito; Shizuma, Toshiyuki; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Seya, Michio; Fujiwara, Mamoru

Proceedings of INMM 51st Annual Meeting (CD-ROM), 10 Pages, 2010/07

We propose a new nondestructive assay method for $$^{235}$$U, $$^{239}$$Pu, and minor actinides in spent nuclear fuel assembly in a water pool. Nuclear fuel materials are detected using nuclear resonance fluorescence (NRF) with laser Compton scattering (LCS) $$gamma$$-rays, which are generated by collision of high energy electrons and laser photons. This method can identify each isotope of interest hidden in heavy shields such as lead plates with a thickness of several centimeters. A simulation calculation shows that we can detect 1% fraction $$^{239}$$Pu in all the fuel rods with statistical error lower than 2% using the proposed high flux LCS $$gamma$$-ray source in the measurement time of 4000s.

Journal Articles

Improvement of SBS laser pulse compression system for the Compton backscattered X-ray source

Kawase, Keigo; Kando, Masaki; Hayakawa, Takehito; Daito, Izuru; Kondo, Shuji; Homma, Takayuki; Kameshima, Takashi*; Kotaki, Hideyuki; Chen, L. M.*; Fukuda, Yuji; et al.

JAEA-Conf 2010-002, p.95 - 98, 2010/06

At the previous symposium in Advanced Photon Research, we proposed and demonstrated the laser pulse compression via stimulated Brillouin scattering (SBS) for increasing the flux of the Compton backscattered X rays. After that, we improved the SBS pulse compression system by introducing the image relay in the laser transport line. As a result, we achieve the stably compressed laser pulse with a duration of 2.1 ns and with an energy of 0.84 J. By installing this system into the Compton backscattered X-ray source, the X-ray flux will be increased 3.2 times for the present system at the KPSI-JAEA.

Journal Articles

An Approach to DNA crystallization using the thermal reversible process of DNA duplexes

Chatake, Toshiyuki*; Sazaki, Gen*; Kikko, Tatsuhiko*; Fujiwara, Satoru; Ishikawa, Takuya*; Matsumoto, Osamu*; Morimoto, Yukio*

Crystal Growth & Design, 10(3), p.1090 - 1095, 2010/03

 Times Cited Count:4 Percentile:48.38(Chemistry, Multidisciplinary)

We propose a technique for DNA crystallization using the thermal reversible process of DNA: a conversion between a double-stranded DNA (dsDNA) and two single-stranded DNAs (ssDNAs) with temperatures. We investigated the solubility of the crystals of a DNA hexamer d(CGCGCG) and their melting temperature, at which the thermal conversion occurs. The results obtained suggest that the conversion from a dsDNA to ssDNAs results in an increase in solubility. It was shown that using this temperature-controlled technique, high-grade single crystals of the DNA hexamer could be obtained from a small amount of DNA samples. This easy-to-apply technique would be superior to the conventional vapor diffusion technique in that it allows the solubility of DNA crystals to be controlled with no need for expensive setups.

Journal Articles

MeV- and sub-MeV-photon sources based on Compton backscattering at SPring-8 and KPSI-JAEA

Kawase, Keigo; Kando, Masaki; Hayakawa, Takehito; Daito, Izuru; Kondo, Shuji; Homma, Takayuki; Kameshima, Takashi; Kotaki, Hideyuki; Chen, L.*; Fukuda, Yuji; et al.

Nuclear Physics Review, 26(Suppl.), p.94 - 99, 2009/07

We constructed MeV- and sub-MeV-photon sources by means of Compton backscattering with a laser light and an electron beam at SPring-8 and KPSI-JAEA. MeV-photon source consists of a continuous-wave optically-pumped far infrared laser and an 8-GeV stored electron beam. Sub-MeV-photon source consists of a Nd:YAG pulse-laser and an 150-MeV electron beam accelerated by a microtron. Both source have been succeeded backscattered photon generation. In this talk, I will present characteristics and future prospects of these photon sources.

Journal Articles

Functional aberration of myofibrils by cardiomyopathy-causing mutations in the coiled-coil region of the troponin-core domain

Matsumoto, Fumiko; Maeda, Kayo*; Chatake, Toshiyuki*; Maeda, Yuichiro*; Fujiwara, Satoru

Biochemical and Biophysical Research Communications, 382(1), p.205 - 209, 2009/04

 Times Cited Count:15 Percentile:37.93(Biochemistry & Molecular Biology)

Two cardiomyopathy-causing mutations, E244D and K247R, in human cardiac troponin T (TnT) are located in the coiled-coil region of the Tn-core domain. To elucidate effects of mutations in this region on the regulatory function of Tn, we measured Ca$$^{2+}$$-dependent ATPase activity of myofibrils containing various mutants of TnT at these residues. The results confirmed that the mutant E244D increases the maximum ATPase activity without changing the Ca$$^{2+}$$ sensitivity. The mutant K247R was shown for the first time to have the effect similar to the mutant E244D. Furthermore, various TnT mutants (E244D, E244M, E244A, E244K, K247R, K247E, and K247A) showed various effects on the maximum ATPase activity while the Ca$$^{2+}$$ sensitivity was unchanged. Molecular dynamics simulations of the Tn-core containing these TnT mutants suggested that the hydrogen-bond network formed by the side chains of neighboring residues around residues 244 and 247 is important for Tn to function properly.

Journal Articles

"J-KAREN"; High intensity laser

Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya*; Tanoue, Manabu*; Akutsu, Atsushi; Okada, Hajime; Motomura, Tomohiro*; Kondo, Shuji; Kanazawa, Shuhei; et al.

JAEA-Conf 2008-007, p.13 - 16, 2008/08

One of the main bottlenecks for the applications of ultrashort and ultrahigh-peak power lasers in high-field physics is a temporal contrast of the pulses. In ultrahigh-peak power lasers, a nanosecond background of the amplified spontaneous emission (ASE) is generated at the same time as the femtosecond pulse. This background is mostly generated in the preamplifier (regenerative, multipass amplifier). Even though the contrast level is usually in the range from 10$$^{-5}$$ to 10$$^{-6}$$, this level is not sufficiently low at relativistic intensities greater than 10$$^{18} $$W/cm$$^{2}$$ to avoid unwanted pre-plasmas generation. We demonstrated a high-contrast, high-peak power laser with optical parametric chirped-pulse amplification (OPCPA). With the use of OPCPA, contrast is enhanced to better than 7$$times$$10$$^{-9}$$ in a few picoseconds before the main pulse, which corresponds to an improvement of three to four orders in magnitude compared with conventional systems.

Journal Articles

Half-life of the $$^{164}$$Ho by the ($$gamma$$,$$n$$) reaction from Laser Compton scattering $$gamma$$ rays at the electron storage ring NewSUBARU

Hayakawa, Takehito; Shizuma, Toshiyuki; Miyamoto, Shuji*; Amano, So*; Horikawa, Ken*; Ishihara, Kazuki*; Mori, Michiaki; Kawase, Keigo; Kando, Masaki; Kikuzawa, Nobuhiro; et al.

Physical Review C, 77(6), p.068801_1 - 068801_4, 2008/06

 Times Cited Count:12 Percentile:61.07(Physics, Nuclear)

no abstracts in English

45 (Records 1-20 displayed on this page)