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Journal Articles

Space weather benchmarks on Japanese society

Ishii, Mamoru*; Shiota, Daiko*; Tao, Chihiro*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Ishii, Takako*; Ichimoto, Kiyoshi*; Kataoka, Ryuho*; Koga, Kiyokazu*; Kubo, Yuki*; et al.

Earth, Planets and Space (Internet), 73(1), p.108_1 - 108_20, 2021/12

 Times Cited Count:1 Percentile:72.01(Geosciences, Multidisciplinary)

We surveyed the relationship between the scale of space weather events and their occurrence rate in Japan and we discussed the social impact of these phenomena during the Project for Solar-Terrestrial Environment Prediction (PSTEP). The information was compiled for domestic users of space weather forecasts for appropriate preparedness against space weather disasters. This paper gives a comprehensive summary of the survey, focusing on the fields of electricity, satellite operations, communication and broadcasting, satellite positioning usage, aviation, human space activity, and daily life on the Earth's surface, using the cutting-edge knowledge of space weather. Quantitative estimations of the economic impact of space weather events on electricity and aviation are also given.

Journal Articles

Narrow-band GeV photons generated from an X-ray free-electron laser oscillator

Hajima, Ryoichi; Fujiwara, Mamoru

Physical Review Accelerators and Beams (Internet), 19(2), p.020702_1 - 020702_9, 2016/02

 Times Cited Count:6 Percentile:52.56(Physics, Nuclear)

We propose a scheme to generate narrow-bandwidth GeV photons, $$gamma$$-rays, via Compton scattering of hard X-ray photons in an X-ray free-electron laser oscillator. Generated $$gamma$$-rays show a narrow-bandwidth spectrum with a sharp peak, $$sim$$0.1% (FWHM), due to large momentum transfer from electrons to photons. Such $$gamma$$-rays will be a unique probe for studying hadron physics. Features of the $$gamma$$-ray source, flux, spectrum, polarization, tunability and energy resolution are discussed.

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:17.22(Physics, Applied)

Journal Articles

Spatial distributions of radionuclides deposited onto ground soil around the Fukushima Dai-ichi Nuclear Power Plant and their temporal change until December 2012

Mikami, Satoshi; Maeyama, Takeshi*; Hoshide, Yoshifumi*; Sakamoto, Ryuichi*; Sato, Shoji*; Okuda, Naotoshi*; Demongeot, S.*; Gurriaran, R.*; Uwamino, Yoshitomo*; Kato, Hiroaki*; et al.

Journal of Environmental Radioactivity, 139, p.320 - 343, 2015/01

 Times Cited Count:70 Percentile:94.06(Environmental Sciences)

Journal Articles

Detailed deposition density maps constructed by large-scale soil sampling for $$gamma$$-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident

Saito, Kimiaki; Tanihata, Isao*; Fujiwara, Mamoru; Saito, Takashi*; Shimoura, Susumu*; Otsuka, Takaharu*; Onda, Yuichi*; Hoshi, Masaharu*; Ikeuchi, Yoshihiro*; Takahashi, Fumiaki; et al.

Journal of Environmental Radioactivity, 139, p.308 - 319, 2015/01

 Times Cited Count:191 Percentile:99.23(Environmental Sciences)

Journal Articles

Non-destructive measurements of nuclear materials in nuclear security

Hayakawa, Takehito; Fujiwara, Mamoru*

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 56(7), p.448 - 452, 2014/07

It is considered that progress of nuclear security is important in the world. A key technology for nuclear security is non-destructive measurements of hidden nuclear materials and radioactive isotopes in various conditions. For such purpose, we require helps of professional in wide range fields as nuclear physics, accelerator science, laser science, and nuclear fusion science etc. outside of the traditional nuclear engineering.

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:36.36(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:53.57(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:40 Percentile:94.29(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

Isoscalar giant resonances in the Sn nuclei and implications for the asymmetry term in the nuclear-matter incompressibility

Li, T.*; Garg, U.*; Liu, Y.*; Marks, R.*; Nayak, B. K.*; Madhusudhana Rao, P. V.*; Fujiwara, Mamoru*; Hashimoto, Hisanobu*; Nakanishi, Kosuke*; Okumura, Shun*; et al.

Physical Review C, 81(3), p.034309_1 - 034309_11, 2010/03

 Times Cited Count:92 Percentile:97.51(Physics, Nuclear)

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

"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

MeV $$gamma$$-ray generation from backward Compton scattering at SPring-8

Kawase, Keigo; Arimoto, Yasushi*; Fujiwara, Mamoru; Okajima, Shigeki*; Shoji, Masazumi*; Suzuki, Shinsuke*; Tamura, Kazuhiro*; Yorita, Tetsuhiko*; Okuma, Haruo*

Nuclear Instruments and Methods in Physics Research A, 592(3), p.154 - 161, 2008/07

 Times Cited Count:19 Percentile:79.01(Instruments & Instrumentation)

A test experimental line at SPring-8 has been constructed for the generation of backward Compton scattered (BCS) $$gamma$$-ray by head-on collision between an 8 GeV electron beam and a far-infrared (FIR) laser. For the FIR laser, we use a continuous-wave methanol laser optically pumped by a carbon dioxide ($${rm CO}_{2}$$) laser. The FIR laser output power achieved is 1.6 W at maximum for 118.8 $$mu$$m lasing; this value is the highest in the case of this type of laser. As a result of the direct measurement, the generated BCS $$gamma$$-ray flux was found to be about $$10^{3}$$ photons/s. This value is consistent with the estimation calculated by taking into account the input laser power and the transmittance of the laser transport system.

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:11 Percentile:60.8(Physics, Nuclear)

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