Measurement of the Se(, n) cross section and uncertainty evaluation of the Se(n, ) cross section

Kitatani, Fumito; Harada, Hideo; Goko, Shinji*; Iwamoto, Nobuyuki; Utsunomiya, Hiroaki*; Akimune, Hidetoshi*; Toyokawa, Hiroyuki*; Yamada, Kawakatsu*; Igashira, Masayuki*

Journal of Nuclear Science and Technology, 53(4), p.475 - 485, 2016/04

https://doi.org/10.1080/00223131.2015.1056760

Development of divertor simulation research in the GAMMA 10/PDX tandem mirror

Nakashima, Yosuke*; Sakamoto, Mizuki*; Yoshikawa, Masayuki*; Oki, Kensuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; et al.

Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10

Development of proposed guideline of flow-induced vibration evaluation for hot-leg piping in a sodium-cooled fast reactor

Sakai, Takaaki; Yamano, Hidemasa; Tanaka, Masaaki; Ono, Ayako; Ohshima, Hiroyuki; Kaneko, Tetsuya*; Hirota, Kazuo*; Sago, Hiromi*; Xu, Y.*; Iwamoto, Yukiharu*; et al.

Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15) (USB Flash Drive), 13 Pages, 2013/05

The development of flow-induced vibration evaluation methodology has reached a milestone that separate-effect experimental data under a high Reynolds number regime including swirl and deflected inflow conditions are available for the validation of the methodology. On the other hand, technical standards are desirable to be documented for designers of sodium-cooled fast reactors. From such a background, the documentation of a flow-induced vibration design guideline has been made for the hot-leg piping of Japan sodium-cooled fast reactor. This paper describes the design guideline of the flow-induced vibration evaluation methodology, which has been informed from main separate-effect experiments, as well as supplemental interpretation for the guideline.

Radioactive tracer Cs (TRACs) for Fukushima Nuclear Power Plant accident

Nagai, Yasuki; Makii, Hiroyuki; Namiki, Shinji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Sawahata, Hiroyuki*

Journal of the Physical Society of Japan, 81(8), p.085003_1 - 085003_2, 2012/08

https://doi.org/10.1143/JPSJ.81.085003

We propose to use the radionuclide Cs as a tracer. -ray energy of the most intense line from the decay of Cs is 668 keV, which is very near to that of the 662 keV from the decay of Cs, while the half-life of Cs is 6.5 d. Cs can be produced by nuclear reactions such as Cs(n,2n)Cs, Cs(r,n)Cs or Xe(p,n)Cs. The Cs tracer would be useful in the quantitative studies of radionuclide Cs contaminant in human, and in any experimental studies in the minimization of radionuclide Cs contamination in agricultural and stock farming products.

X-ray diffraction recording from single axonemes of eukaryotic flagella

Nishiura, Masaya*; Toba, Shiori*; Takao, Daisuke*; Miyashiro, Daisuke*; Sakakibara, Hitoshi*; Matsuo, Tatsuhito; Kamimura, Shinji*; Oiwa, Kazuhiro*; Yagi, Naoto*; Iwamoto, Hiroyuki*

Journal of Structural Biology, 178(3), p.329 - 337, 2012/06

https://doi.org/10.1016/j.jsb.2012.03.011

We report the first X-ray diffraction patterns recorded from single axonemes of eukaryotic flagella with a diameter of only 0.2 m, by using the technique of cryomicrodiffraction. A spermatozoon isolated from Drosophila melanogaster, was mounted straight in a glass capillary, quickly frozen and its 800-m segment was irradiated end-on with intense synchrotron radiation X-ray microbeams (diameter, 2 m) at 74 K. Well-defined diffraction patterns were recorded, consisting of a large number of isolated reflection spots. The patterns had features of an 18-fold rotational symmetry as expected from the axonemal structure. The diffraction patterns were compared with the results of model calculations based on a published electron micrograph of the Drosophila axoneme. The comparison provided information on the native state of axoneme, including estimates of axonemal diameter and interdoublet spacing.

Defects in an electron-irradiated 6H-SiC diode studied by alpha particle induced charge transient spectroscopy; Their impact on the degraded charge collection efficiency

Iwamoto, Naoya*; Koizumi, Atsushi*; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi; Kojima, Kazutoshi*; Koike, Shumpei*; Uchida, Kazuo*; Nozaki, Shinji*

Materials Science Forum, 717-720, p.267 - 270, 2012/05

https://doi.org/10.4028/www.scientific.net/MSF.717-720.267

In this study, we carried out an attempt to identify the defects responsible for the degraded charge collection efficiency of the 6H-SiC pn diode irradiated with 1 MeV electrons by the alpha particle induced charge transient spectroscopy. To form defects in the SiC crystal, one of the diodes was irradiated with 1 MeV electrons at a fluence of 110 /cm. Collected charges of the diodes were measured in room temperature using 5.486 MeV alpha particles from Am source. After the electron irradiation, the collected charge of the diode at a reverse bias of 100 V decreased to 84% of its initial value. In order to investigate the relationship between degradation of collected charge and defects in detail, time-dependent collected charges of the diodes were measured in temperature ranges from 170 K to 310 K. As a result, two distinct peaks labeled X and X are found for the electron-irradiated diode, and their activation energies are estimated to be 0.30 and 0.47 eV, respectively. These two peaks are considered to correspond to the defect levels introduced by the electron irradiation. In particular, when the diodes are used in room temperature, X is more critical to the charge collection than X.

Photoneutron cross sections for Sn and the -ray strength function method

Utsunomiya, Hiroaki*; Goriely, S.*; Kamata, Masaki*; Akimune, Hidetoshi*; Kondo, Takeo*; Ito, Osamu*; Iwamoto, Chihiro*; Yamagata, Tamio*; Toyokawa, Hiroyuki*; Lui, Y.-W.*; et al.

Physical Review C, 84(5), p.055805_1 - 055805_6, 2011/11

https://doi.org/10.1103/PhysRevC.84.055805

Photoneutron cross sections were measured for Sn, Sn, Sn, Sn, and Sn near neutron threshold with quasi-monochromatic laser-Compton scattering -rays. A systematic analysis of the present photoneutron data and existing neutron-capture data is made using the -ray strength function on the basis of the HFB+QRPA model of E1 strength supplemented with a pygmy dipole resonance, which was deduced from a previous study on Sn and Sn. Radiative neutron capture cross sections for two radioactive nuclei, Sn and Sn, are deduced through the -ray strength function method.

Application of the SF method to palladium

Utsunomiya, Hiroaki*; Goriely, S.*; Arteaga, D. P.*; Daoutidis, I.*; Akimune, Hidetoshi*; Yamagata, Tamio*; Kondo, Takeo*; Iwamoto, Chihiro*; Kamata, Masaki*; Ito, Osamu*; et al.

AIP Conference Proceedings 1377, p.450 - 452, 2011/10

https://doi.org/10.1063/1.3628442

Oxygen ion induced charge in SiC MOS capacitors irradiated with -rays

Oshima, Takeshi; Iwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Nozaki, Shinji*; Kojima, Kazutoshi*

Materials Science Forum, 679-680, p.362 - 365, 2011/03

https://doi.org/10.4028/www.scientific.net/MSF.679-680.362

Charge induced in the 6H-Silicon Carbide (SiC) n Metal-Oxide-Semiconductor (MOS) capacitors by 15 MeV oxygen ion microbeams was evaluated using Transient Ion Beam Induced Current (TIBIC) before and after -ray irradiations. With increasing number of incident ions, the peak height of TIBIC signals decreases and the fall time increases. The decrease in TIBIC peak finally saturated. The peak height of the TIBIC signal can be refreshed to its original shape by applying a positive bias of + 1V to the oxide electrode. This result can be explained in terms of the existence of deep hole traps. Small decrease in both TIBIC signal peak and collected charge was observed due to -ray irradiation.

Charge enhancement effects in 6H-SiC MOSFETs induced by heavy ion strike

Onoda, Shinobu; Makino, Takahiro; Iwamoto, Naoya*; Vizkelethy, G.*; Kojima, Kazutoshi*; Nozaki, Shinji*; Oshima, Takeshi

IEEE Transactions on Nuclear Science, 57(6), p.3373 - 3379, 2010/12

no abstracts in English