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Journal Articles

Beam instruments for high power spallation neutron source and facility for ADS

Meigo, Shinichiro

Proceedings of 61st ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB 2018) (Internet), p.99 - 103, 2018/07

As the increase of beam power, beam instruments play an essential role in the Hadron accelerator facility. In J-PARC, the pitting erosion on the mercury target vessel for the spallation neutron source is one of a pivotal issue to operate with the high power of the beam operation. Since the erosion is proportional to the 4th power of the beam current density, the minimization of the peak current density is required. To achieve low current density, the beam-flattening system by nonlinear beam optics in J-PARC, by which the peak density was successfully reduced by 30% than the density with the conventional case optics. Since the ADS requires a very powerful accelerator with the beam power such as 30 MW, a robust beam profile monitor is required, especially for the observation of the beam status on the target continuously. A candidate material for the beam monitor was developed by using heavy-ion of Ar beam to give the damage efficiently.

Journal Articles

Numerical simulation of hydrogen thermal desorption profile under assumption of two kinds of trap sites for tempered martensitic steel

Tsuchida, Yutaka*; Ebihara, Kenichi

Tetsu To Hagane, 103(11), p.653 - 659, 2017/11

 Percentile:100(Metallurgy & Metallurgical Engineering)

A single peak in thermal desorption profiles of hydrogen, which are measured in low-temperature thermal desorption spectrometry (L-TDS) for a very thin plate specimen of tempered martensitic steel, was reproduced successfully by the superposition of two Gaussian distributions. Then, the parameters concerning the detrapping rate constants for both peaks, which are trap energy and pre-exponential factor, were calculated using the Choo-Lee plot. We confirmed that Kissinger model incorporating the obtained parameters could simulate the two peaks. In addition, we reproduced the single peak well using the reaction-diffusion equation incorporating the obtained parameters and the appropriate trap site concentration. From the results, we interpreted that the one peak corresponds to dislocation and the other to grain-boundary.

Journal Articles

Relaxation time of radiation-induced radicals in $$gamma$$-ray irradiated amino acids

Nagata, Natsuki*; Komoda, Seiichi*; Kikuchi, Masahiro; Nakamura, Hideo*; Kobayashi, Yasuhiko; Ukai, Mitsuko*

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 103, 2016/02

no abstracts in English

Journal Articles

Research and development of high intensity beam transport to the target facilities at J-PARC

Meigo, Shinichiro; Oi, Motoki; Ikezaki, Kiyomi*; Kawasaki, Tomoyuki; Kinoshita, Hidetaka; Akutsu, Atsushi*; Nishikawa, Masaaki*; Fukuda, Shimpei

Proceedings of 12th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '15), p.255 - 260, 2016/00

Journal Articles

Peak-fitting analysis with Gaussian line shapes against experimental ESR spectrum consisting of multiple peak

Kikuchi, Masahiro; Nagata, Natsuki*; Komoda, Seiichi*; Kameya, Hiromi*; Ukai, Mitsuko*; Kobayashi, Yasuhiko

Shokuhin Shosha, 50(1), p.13 - 19, 2015/10

no abstracts in English

Journal Articles

DPA Calculation in 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:21 Percentile:14.34(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.

Journal Articles

Protein boson peak originated from hydration-related multiple minima energy landscape

Jochi, Yasumasa*; Kitao, Akio*; Go, Nobuhiro

Journal of the American Chemical Society, 127(24), p.8705 - 8709, 2005/06

 Times Cited Count:23 Percentile:38.54(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Validation of simplified evaluation models for first peak power, energy, and total fissions of a criticality accident in a nuclear fuel processing facility by TRACY experiments

Nomura, Yasushi*; Okuno, Hiroshi; Miyoshi, Yoshinori

Nuclear Technology, 148(3), p.235 - 243, 2004/12

 Times Cited Count:3 Percentile:73(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Improvement of instantaneous measurement-type void fraction meter; Design of high speed response rectifier

Shibamoto, Yasuteru; Sagawa, Jun*; Iguchi, Tadashi; Nakamura, Hideo

JAERI-Tech 2003-056, 29 Pages, 2003/06

JAERI-Tech-2003-056.pdf:3.24MB

no abstracts in English

Journal Articles

Sideward peak of intermediate mass fragments in high energy proton induced reactions

Hirata, Yuichi*; Onishi, Akira*; Nara, Yasushi*; Kido, Toshihiko; Maruyama, Toshiki; Otsuka, Naohiko*; Niita, Koji*; Takada, Hiroshi; Chiba, Satoshi

Nuclear Physics A, 707(1-2), p.193 - 212, 2002/08

 Times Cited Count:10 Percentile:44.69

no abstracts in English

Journal Articles

Improved high-field laser characteristics of a diode-pumped Yb:LiYF$$_{4}$$ crystal at low temperature

Kawanaka, Junji; Yamakawa, Koichi; Nishioka, Hajime*; Ueda, Kenichi*

Optics Express (Internet), 10(10), p.455 - 460, 2002/05

 Times Cited Count:31 Percentile:20.89(Optics)

no abstracts in English

JAEA Reports

Determination of neptunium in neptunium-uranium-plutonium mixed oxide fuel by spectrophotometry.

; ; ; ; ; *; *

JNC-TN8400 2001-026, 29 Pages, 2001/12

JNC-TN8400-2001-026.pdf:0.99MB

The measurement condition by spectrophotometry was evaluated to measure Np content in MOX fuel containing Np. The Np concentration was obtained by measuring the 727nm absorption peak, after the valence of Np in the sample solution was adjusted to the Np(Ⅳ). The calibration curve showed the linearity up to Np concentration 0.8mg/ml. Though Pu and U quantity were respectively added to the Np solution to 30 times and 60 times of Np concentration, there was no effect to the Np analysis. By using this method, relative standard deviation (RSD) of the analyzed values of Np content for 2%Np - MOX fuel was about 4%. In addition, It was confirmed that the Np content could be measured without separating Np from Pu and U. This method can be sufficiently applied as a quick simple method to analyze Np content in MOX fuel containing Np.

Journal Articles

Application of Ge semi-conductor detector to whole-body counter

Kinase, Sakae; Noguchi, Hiroshi; Nakamura, Takashi*

KEK Proceedings 2001-22, p.30 - 36, 2001/12

no abstracts in English

Journal Articles

Deep-level transient spectroscopy analysis of proton-irradiated n$$^{+}$$/p InGaP solar cell

Dharmarasu, N.*; Yamaguchi, Masafumi*; Khan, K.*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; Matsuda, Sumio*

Physica B; Condensed Matter, 308-310, p.1181 - 1184, 2001/12

 Times Cited Count:6 Percentile:59.35

Carrier concentration and defects in n+/p InGaP irradiated with 100keV-protons (1E10, 5E12 /cm2) were studied.As a result of C-V measurements, the carrier removal rate was estimated to be 6.1E4 /cm2 which was extremely high as compared to 1MeV-electron irradiation case (0.93 /cm). H1 peak whose energy corresponds to Ev+0.90V was obtained from DLTS measurements. This suggests that carrier removal rate in proton-irradiated ones is much higher than that in electron-irradiated ones due to the generation of the defects (H1 peak) which act as majority carrier traps.

Journal Articles

Application of Monte Carlo simulations for evaluating efficiency curves of Ge detector

Saegusa, Jun

Hokeikyo Nyusu, (28), p.2 - 5, 2001/10

no abstracts in English

JAEA Reports

Spatial distribution effect of feedback reactivity in TRACY experiments; Evaluation of the first power peak characteristics

Obara, Toru*; Nakajima, Ken; Miyoshi, Yoshinori; Sekimoto, Hiroshi*

JAERI-Research 2001-037, 60 Pages, 2001/06

JAERI-Research-2001-037.pdf:2.7MB

no abstracts in English

Journal Articles

Neutron inelastic scattering study of densified GeO$$_{2}$$ glass

Suzuya, Kentaro; Shibata, Kaoru*; Umesaki, Norimasa*; Kitamura, Naoyuki*; Kohara, Shinji*

Journal of the Physical Society of Japan, Vol.70, Supplement A, p.256 - 258, 2001/05

no abstracts in English

JAEA Reports

Study of vibrational spectra of interlayer water in Na-Smectite by means of molecular dynamics simulations

; Kawamura, Katsuyuki*

JNC-TN8400 2001-005, 41 Pages, 2001/04

JNC-TN8400-2001-005.pdf:1.1MB

A correlation between molecular structure and a vibrational spectrum of interlayer water in Na-smectite was investigated by means of Molecular Dymamics (MDs) simulations. Detailed comparison of simulation results with IR spectroscopic observations for the water-smectite system indicated good agreement. Internal vibrational spectra of water were obtained by the Fourier transformation of velocty auto-correlation function of hydrogen atom. A stretching vibrational spectrum of interlayer water consisted of a broad band with a peak top around 3400cm$$^{-1}$$ and a sharp peak around 3650 to 3700cm$$^{-1}$$. The fomer broad band was assigned to O-H vibrations between water molecules as bulk water, while the latter band was attributed to O-H ones oriented to siloxane surface through hydrogen bonding. The hydrogen bond distance, determined as the shortest O-O distance by the radial distribution function (RDF), revealed that hydrogen bond distance between water and siloxane surface (O$$_{H2O}$$-O$$_{clay}$$ $$>$$ 3.0 $AA )was larger than that between water molecules (O$_{H2O}$$-O$$_{H2O}$$ = ca. 2.8 AA ). These results suggested that interaction between water molecule and siloxane surface weaker than that between water molecules, although they were forced to be oriented.

Journal Articles

Prospects of high-field science

Kato, Yoshiaki

Reza Kenkyu, 29(4), p.211 - 217, 2001/04

no abstracts in English

Journal Articles

Challenge to ultra short time phenomena using T3 laser

Kato, Yoshiaki

Enerugi, 34(3), p.50 - 53, 2001/03

no abstracts in English

77 (Records 1-20 displayed on this page)