PSTEP: Project for solar-terrestrial environment prediction

Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.

Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12

https://doi.org/10.1186/s40623-021-01486-1

The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

Preliminary test of the EA-AGE3 system for C measurement of CaCO samples and coral-based estimation of marine reservoir correction in the Ogasawara Islands, Northwestern Subtropical Pacific

Kokubu, Yoko; Mitsuguchi, Takehiro*; Watanabe, Takahiro; Yamada, Tsutomu*; Asami, Ryuji*; Iryu, Yasufumi*

Radiocarbon, 61(5), p.1593 - 1601, 2019/10

https://doi.org/10.1017/RDC.2019.69

We performed C measurements of two fossil and one modern corals using a combined system of an elemental analyzer and an automated graphitization equipment AGE3 (EA-AGE3 system) and JAEA-AMS-TONO. The C concentrations (pMC values) of mid-Holocene Okinawa corals obtained by our EA-AGE3 system appear to be slightly higher than those obtained by the conventional graphitization method using phosphoric acid. The pMC increase in our EA-AGE3 system may result in significant underestimation of C age especially for older samples (e.g., 10,000 BP); however, the pMC increase is negligible in C measurements of modern or recent samples. We applied the EA-AGE3 method to the pre- and post-bomb annual-band samples from the modern Ogasawara coral for C measurements. On the basis of the pre-bomb coral C data, we estimated marine reservoir correction (R) around Ogasawara Islands and its stability between 1900 and 1950 AD.

Role of multichance fission in the description of fission-fragment mass distributions at high energies

Hirose, Kentaro; Nishio, Katsuhisa; Tanaka, Shoya*; Lguillon, R.*; Makii, Hiroyuki; Nishinaka, Ichiro*; Orlandi, R.; Tsukada, Kazuaki; Smallcombe, J.*; Vermeulen, M. J.; et al.

Physical Review Letters, 119(22), p.222501_1 - 222501_6, 2017/12

https://doi.org/10.1103/PhysRevLett.119.222501

Fission-fragment mass distributions were measured for U, Np and Pu populated in the excitation-energy range from 10 to 60 MeV by multi-nucleon transfer channels in the reaction O + U at the JAEA tandem facility. Among them, the data for U and Np were observed for the first time. It was found that the mass distributions for all the studied nuclides maintain a double-humped shape up to the highest measured energy in contrast to expectations of predominantly symmetric fission due to the washing out of nuclear shell effects. From a comparison with the dynamical calculation based on the fluctuation-dissipation model, this behavior of the mass distributions was unambiguously attributed to the effect of multi-chance fission.

Examination of decontamination of various materials at houses in difficult-to-return zone

Mori, Airi; Tanabe, Tsutomu; Wada, Takao; Kato, Mitsugu

JAEA-Technology 2017-006, 38 Pages, 2017/03

JAEA-Technology-2017-006.pdf:2.98MB

Large quantities of radioactive materials were released into the environment as a result of the Fukushima Daiichi Nuclear Power Station accident. Residential areas and forest areas near the power station were contaminated with the radioactive materials. Outside of the houses, schools and the other buildings are being decontaminated by national authority and local government. On the other hand, the materials (such as walls, floors, or windows) which constitute the houses are not decontaminated officially. In order to prepare decontamination methods that can be applied easily, we conducted examinations of decontamination for various materials in houses. Fibrous materials, woods, glasses, concretes, plastics, vinyl chloride materials, metals and synthetic leathers were used in our examinations. These materials were collected from houses in difficult-to-return zone, and were contaminated by radioactive materials released by the accident. Dry methods (suction, wiping, adsorption and peelable coating), wet methods (wiping, brushing, polishing and washing) and physical method (peeling of materials) were used for decontamination. As a result of our examinations, materials with low water permeability, such as glasses, concretes, vinyl chloride materials and metals, were able to be decontaminated efficiently (about 90% reduction) by using wet methods. Materials with high water permeability like woods were relatively well decontaminated by peelable coating (about 60%-70% reduction). In addition to the examination described above, the difference of contamination reduction effect between chemical properties of detergents and the effect of rubbing of peelable coating were also examined. Finally, the most effective method was summarized based on these examinations.

Overview of JENDL-4.0/HE and benchmark calculations

Kunieda, Satoshi; Iwamoto, Osamu; Iwamoto, Nobuyuki; Minato, Futoshi; Okamoto, Tsutomu; Sato, Tatsuhiko; Nakashima, Hiroshi; Iwamoto, Yosuke; Iwamoto, Hiroki; Kitatani, Fumito; et al.

JAEA-Conf 2016-004, p.41 - 46, 2016/09

https://doi.org/10.11484/jaea-conf-2016-004

Neutron- and proton-induced cross-section data are required in a wide energy range beyond 20 MeV, for the design of accelerator applications. New evaluations are performed with recent knowledge in the optical and pre-equilibrium model calculations. We also evaluated cross-sections for p+Li and p+Be which have been highly requested from a medical field. The present high-energy nuclear data library, JENDL-4.0/HE, includes evaluated cross-sections for incident neutrons and protons up to 200 MeV (for about 130 nuclei). We overview substantial features of the library, i.e., (1) systematic evaluation with CCONE code, (2) challenges for evaluations of light nuclei and (3) inheritance of JENDL-4.0 and JENDL/HE-2007. In this talk, we also focus on the results of benchmark calculation for neutronics to show performance of the present library.

Nucleoside diphosphate kinase from psychrophilic sp. AS-131 isolated from Antarctic Ocean

Yonezawa, Yasushi*; Nagayama, Aiko*; Tokunaga, Hiroko*; Ishibashi, Matsujiro*; Arai, Shigeki; Kuroki, Ryota; Watanabe, Keiichi*; Arakawa, Tsutomu*; Tokunaga, Masao*

Protein Journal, 34(4), p.275 - 283, 2015/08

https://doi.org/10.1007/s10930-015-9623-0

Nucleoside diphosphate kinase isolated from psychrophilic sp. AS-131 (ASNDK) was expressed in and purified to homogeneity. Comparing to mesophilic NDK isolated from , ASNDK exhibited highly elevated thermolability: (1) expression at 37C as a denatured insoluble form, and (2) 30C lower optimum temperature of enzymatic activity. The subunit structure of ASNDK was suggested to be dimer, as in NDKs isolated from moderate halophiles.

Thermal expansion of a Au-Al-Yb intermediate valence quasicrystal

Watanuki, Tetsu; Kashimoto, Shiro*; Ishimasa, Tsutomu*; Machida, Akihiko; Yamamoto, Shin*; Tanaka, Yukinori*; Mizumaki, Masaichiro*; Kawamura, Naomi*; Watanabe, Shinji*

Solid State Communications, 211, p.19 - 22, 2015/06

https://doi.org/10.1016/j.ssc.2015.03.008

The thermal expansion of a Au-Al-Yb intermediate-valence quasicrystal has been studied by X-ray diffraction measurements. We have found anomalous thermal expansion behavior, namely zero thermal expansion below 50 K. By comparison with an isostructural Au-Al-Tm quasicrystal, the contribution of the Yb valence variation was extracted, and it was shown that its negative thermal expansion component due to the valence shift toward the divalent state by cooling compensated for the positive thermal expansion of the original lattice.

Development of a resonant laser ionization gas cell for high-energy, short-lived nuclei

Sonoda, Tetsu*; Wada, Michiharu*; Tomita, Hideki*; Sakamoto, Chika*; Takatsuka, Takaaki*; Furukawa, Takeshi*; Iimura, Hideki; Ito, Yuta*; Kubo, Toshiyuki*; Matsuo, Yukari*; et al.

Nuclear Instruments and Methods in Physics Research B, 295, p.1 - 10, 2013/01

https://doi.org/10.1016/j.nimb.2012.10.009

no abstracts in English

Nuclear orientation in the reaction S+U and synthesis of the new isotope Hs

Nishio, Katsuhisa; Hofmann, S.*; Heberger, F. P.*; Ackermann, D.*; Antalic, S.*; Aritomo, Yoshihiro; Comas, V. F.*; Dllmann, Ch. E.*; Gorshkov, A.*; Graeger, R.*; et al.

Physical Review C, 82(2), p.024611_1 - 024611_9, 2010/08

https://doi.org/10.1103/PhysRevC.82.024611

Effects of nuclear orientation on fusion and fission process for reactions using uranium target nuclei

Nishio, Katsuhisa; Ikezoe, Hiroshi; Mitsuoka, Shinichi; Nishinaka, Ichiro; Makii, Hiroyuki; Watanabe, Yutaka*; Nagame, Yuichiro; Otsuki, Tsutomu*; Hirose, Kentaro*; Hofmann, S.*

AIP Conference Proceedings 1224, p.301 - 310, 2010/04

https://doi.org/10.1063/1.3431429