Displacement of hydrogen position in di-hydride of V-Ti-Cr solid solution alloys

Sakaki, Koji*; Kim, H.*; Majzoub, E. H.*; Machida, Akihiko*; Watanuki, Tetsu*; Ikeda, Kazutaka*; Otomo, Toshiya*; Mizuno, Masataka*; Matsumura, Daiju; Nakamura, Yumiko*

Acta Materialia, 234, p.118055_1 - 118055_10, 2022/08

https://doi.org/10.1016/j.actamat.2022.118055

On-site training using JMTR and related facilities in FY2014

Eguchi, Shohei; Takemoto, Noriyuki; Tanimoto, Masataka; Kubo, Ayako; Ishitsuka, Etsuo; Nakamura, Jinichi; Ito, Haruhiko

JAEA-Review 2015-005, 38 Pages, 2015/06

JAEA-Review-2015-005.pdf:15.06MB

Since fiscal 2011, a practical training course using the JMTR and other research infrastructures has been provided by Neutron Irradiation Testing Reactor Center for foreign young researchers and engineers in Asian and other countries which are planning to introduce power reactors. The aim of this course is to contribute to the human resource development in nuclear research field and to increase the future use the JMTR. On the other hand, a training course for Japanese young researchers and engineers has been conducted since fiscal 2010. In fiscal 2014, these two separate courses were integrated into one and it was conducted for 3 weeks for young researchers and engineers at home as well as abroad. Nineteen persons from seven countries participated and they studied about the general outline of nuclear research, current status and R&D of nuclear energy, irradiation test facilities and technologies, nuclear characteristics of the reactor and safety and operation management of nuclear reactors. At the end of the course, we had an active discussion about the current status and future of energy mix. The content of this training course in fiscal 2014 are reported in this paper.

Development of new in-pile instrumentation at JMTR

Shibata, Akira; Kimura, Nobuaki; Tanimoto, Masataka; Nakamura, Jinichi; Saito, Takashi; Tsuchiya, Kunihiko

JAEA-Conf 2012-002, p.56 - 60, 2012/12

https://jopss.jaea.go.jp/pdfdata/JAEA-Conf-2012-002.pdf#page=66

To improve the quality of irradiation tests data and to increase the reliability of safety management system of reactors including both MTR and LWR, development of new instrumentation is key issue. JAEA is developing several in-pile instrumentations to conduct irradiation tests at JMTR. Here we introduce three new instrumentations. These are ECP sensor, new water level indicator and in-reactor observation system using Cherenkov light.

Development of instrumentation for international standard

Tanimoto, Masataka; Aoyama, Masashi; Kitagishi, Shigeru; Shibata, Akira; Saito, Takashi; Nakamura, Jinichi; Tsuchiya, Kunihiko

Proceedings of 1st Asian Symposium on Material Testing Reactors (ASMTR 2011), p.62 - 70, 2011/02

The new JMTR is expected to contribute to many fields: the lifetime extension of LWRs (aging management of LWRs, development of next generation LWRs, etc.), the expansion of industry use (production of the medical radioisotope Tc, etc.) and the progress of science and technology (namely, basic research on nuclear energy). To meet a wide range of users needs, new irradiation technologies with advanced techniques have been developed. In this paper, status of the development of new measuring instruments are introduced which for neutron and irradiation tests in JMTR such as multi-paired thermocouple, rod inner pressure gauge, Self-Powered Neutron Detector (SPND) and Self-Powered Gamma Detector (SPGD).

Synthesis of pinguisane-type sesquiterpenoids acutifolone A, pinguisenol, and bisacutifolones by a Diels-Alder dimerization reaction

Shiina, Junichi*; Oikawa, Masataka; Nakamura, Kensuke; Obata, Rika*; Nishiyama, Shigeru*

European Journal of Organic Chemistry, 2007(31), p.5190 - 5197, 2007/11

https://doi.org/10.1002/ejoc.200700522

It is important to synthesize bio-active compounds which will affect DNA repair system. The total synthesis of pinguisane-type sesquiterpenoids, acutifolone A and pinguisenol, has been achieved by using the Mukaiyama aldol reaction as the key step. The intermolecular Diels-Alder reaction of these monomeric natural products successfully led to stereoselective dimerization, leading to bisacutifolones A and B. Theoretical calculations revealed that the dimerization reaction proceeded through the most stable transition state.

High quality laser-produced proton beam generation by phase rotation

Noda, Akira*; Nakamura, Shu*; Iwashita, Yoshihisa*; Shirai, Toshiyuki*; Tongu, Hiromu*; Soda, Hikaru*; Daido, Hiroyuki; Mori, Michiaki; Kado, Masataka; Sagisaka, Akito; et al.

International Journal of Modern Physics B, 21(3&4), p.319 - 330, 2007/02

Laser ion production has been studied for downsizing of the accelerator dedicated for cancer therapy. For optimization of various parameters such as pre-pulse condition, target position, laser spot size on target, laser pulse width and so on, time of flight (TOF) measurement utilizing the detected signal by a plastic scintillation counter played an essential role for real time measurement. Protons up to 900 keV and 600 keV are produced from the thin foil targets of Ti 3 micron and 5 micron in thickness, respectively. Modification of the energy distribution of the laser-produced ions with Maxwell distribution by utilizing an RF electric field synchronized to the pulse laser, which is the rotation of the ion beam in the longitudinal phase space (phase rotation), has been demonstrated for the first time.

Estimation of photon dose generated by a short pulse high power laser

Hayashi, Yukio; Fukumi, Atsushi*; Matsukado, Koji*; Mori, Michiaki; Kotaki, Hideyuki; Kando, Masaki; Chen, L.-M.; Daito, Izuru; Kondo, Shuji; Kanazawa, Shuhei; et al.

Radiation Protection Dosimetry, 121(2), p.99 - 107, 2006/12

https://doi.org/10.1093/rpd/nci383

The authors obtain a new equation to estimate the forward component of a photon dose which is generated through the interaction between a target and a short pulse high power laser. As the equation is quite simple, it is useful for calculating the photon dose. The equation shows that the photon dose is proportional to the electron temperature for the range of its temperature 3 MeV, and proportional to square of the electron temperature for the range of its temperature 3 MeV. The dose estimated with this method is roughly consistent with the result of Monte Carlo simulation. On someassumptions and corrections, it can reproduce experimental results obtained and the dose result calculated at other laboratories.

New detection device for Thomson parabola spectrometer for diagnosis of the laser-plasma ion beam

Mori, Michiaki; Kando, Masaki; Pirozhkov, A. S.; Hayashi, Yukio; Yogo, Akifumi; Yoshimura, Norihisa; Ogura, Koichi; Takai, Mamiko; Sagisaka, Akito; Orimo, Satoshi; et al.

Plasma and Fusion Research (Internet), 1(9), p.042_1 - 042_4, 2006/09

A new detection device for evaluating ion energy distributions for laser-plasma ion source is demonstrated. The Imaging Plate (IP) with no protective layer as ion detector device for the Thomson Parabola spectrometeris used. The Imaging Plate Thomson Parabola spectrometer (IPTPS) is applicable for the analysis of the energydistribution of the laser-driven ion beam using an opto-electric digitizing technique.

Enhancement of high energy proton yield with a polystyrene-coated metal target driven by a high-intensity femtosecond laser

Yogo, Akifumi; Nishiuchi, Mamiko; Fukumi, Atsushi*; Li, Z.*; Ogura, Koichi; Sagisaka, Akito; Orimo, Satoshi; Kado, Masataka; Hayashi, Yukio; Mori, Michiaki; et al.

Applied Physics B, 83(4), p.487 - 489, 2006/06

https://doi.org/10.1007/s00340-006-2248-4

We present experimental results on protons accelerated up to 950 keV from a 3-m thick tantalum foil with a 133-nm thick polystyrene layer on its rear surface, irradiated with a laser pulse having the duration of 70 fs and the intensity of W/cm. The energy distribution of fast protons was measured simultaneously with that of the hot-electrons from the rear surface. The proton yield from the polystyrene-coated target is about 10 times as high as that from the uncoated metal target. This enhancement of the proton yield is roughly proportional to the increase of hydrogen atoms given by the 133-nm thick polystyrene layer, assuming a contaminant layer of 10-nm thickness is on the metal surface without coating. This result shows that the polystyrene layer contributes to the yield enhancement.

Characterization of JT-60U exhaust gas during experimental operation

Isobe, Kanetsugu; Nakamura, Hirofumi; Kaminaga, Atsushi; Tsuzuki, Kazuhiro; Higashijima, Satoru; Nishi, Masataka; Kobayashi, Yasunori*; Konishi, Satoshi*

Fusion Engineering and Design, 81(1-7), p.827 - 832, 2006/02

https://doi.org/10.1016/j.fusengdes.2005.09.039

Exhaust gas from JT-60U during experimental operation has been measured with Gas Chromatography (GC), and the gas exhaust characteristic from JT-60U on plasma discharge conditions has been investigated during the JT-60U experimental campaign in 2003-2004. During experimental operation of JT-60U, hydrogen isotope concentration strongly depended on the type of discharges such as high performance, long pulse and so on. On the other hand, impurity species, such as helium, hydrocarbon and carbon oxide, were detected during plasma discharges occasionally. During the experimental operation, plasma disruption remarkably tended to produce high concentration impurities. Glow discharge and Taylor discharge for wall conditioning also produced impurities. In the case of normal plasma, impurity was detected and high performance plasma, such as high plasma, tended to produce high concentration impurities. This result indicated that impurities concentration might be higher in the case of normal plasma in ITER, because of its high performance.