A Sensitive method for Sr-90 analysis by accelerator mass spectrometry

Sasa, Kimikazu*; Honda, Maki; Hosoya, Seiji*; Takahashi, Tsutomu*; Takano, Kenta*; Ochiai, Yuta*; Sakaguchi, Aya*; Kurita, Saori*; Satou, Yukihiko; Sueki, Keisuke*

Journal of Nuclear Science and Technology, 58(1), p.72 - 79, 2021/01

https://doi.org/10.1080/00223131.2020.1801530

Compositional and structural analysis of Fukushima-derived particulates using high-resolution X-ray imaging and synchrotron characterisation techniques

Martin, P. G.*; Jones, C. P.*; Cipiccia, S.*; Batey, D. J.*; Hallam, K. R.*; Satou, Yukihiko; Griffiths, I.*; Rau, C.*; Richards, D. A.*; Sueki, Keisuke*; et al.

Scientific Reports (Internet), 10(1), p.1636_1 - 1636_11, 2020/01

https://doi.org/10.1038/s41598-020-58545-y

Activity of Sr in fallout particles collected in the difficult-to-return zone around the Fukushima Daiichi Nuclear Power Plant

Zhang, Z.*; Igarashi, Junya*; Satou, Yukihiko; Ninomiya, Kazuhiko*; Sueki, Keisuke*; Shinohara, Atsushi*

Environmental Science & Technology, 53(10), p.5868 - 5876, 2019/05

https://doi.org/10.1021/acs.est.8b06769

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released abundant radioactive particles into the surrounding environment. Herein, we analyzed the activity of Sr in these particles to estimate the contribution of this radionuclide to the overall radiation exposure and shed light on the processes that occurred during the accident. Seven radioactive particles were isolated from the dust and soil samples collected from areas surrounding the FDNPP, and the minimum/maximum Cs activities were determined as 224/4,100 Bq. Based on the size, specific activity, and Cs/Cs activity ratios, we concluded that six of the seven radioactive particles were released from the Unit 1 reactor, while one particle was released from the Unit 3 reactor by a hydrogen explosion. Strontium-90 was detected in all radioactive particles, and the minimal/maximal Sr activities were determined as 0.046/1.4 Bq. Cs/Sr activity ratios above 1000 were observed for all seven particles, that is, compared to Cs, Sr had negligible contribution to the overall radiation exposure. The Cs/Sr activity ratios of the radioactive particles were similar to those of terrestrial environmental samples and were higher for particles released from the Unit 1 reactor than for samples collected from the Unit 1 reactor building, which indicates possibility of additional Sr -rich contamination after release of the particles.

Radiocarbon variations in tree rings since 1960 near the Tokai nuclear facility, Japan

Matsunaka, Tetsuya*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Hosoya, Seiji*; Matsumura, Masumi*; Satou, Yukihiko; Shen, H.*; Sueki, Keisuke*

Nuclear Instruments and Methods in Physics Research B, 439, p.64 - 69, 2019/01

https://doi.org/10.1016/j.nimb.2018.12.009

no abstracts in English

Decontamination by removing radiocaesium on polluted bark of cherry trees in northern Fukushima Prefecture following the TEPCO's Fukushima Dai-ichi Nuclear Power Plant Accident

Sugiura, Hiroyuki*; Sakai, Hajime*; Satou, Yukihiko; Sueki, Keisuke*

Radioisotopes, 66(9), p.311 - 319, 2017/09

https://doi.org/10.3769/radioisotopes.66.311

no abstracts in English

Investigation of the chemical characteristics of individual radioactive microparticles emitted from reactor 1 by the Fukushima Daiichi Nuclear Power Plant accident by using multiple synchrotron radiation X-ray analyses

Ono, Takahiro*; Iizawa, Yushin*; Abe, Yoshinari*; Nakai, Izumi*; Terada, Yasuko*; Satou, Yukihiko; Sueki, Keisuke*; Adachi, Koji*; Igarashi, Yasuhito*

Bunseki Kagaku, 66(4), p.251 - 261, 2017/04

https://doi.org/10.2116/bunsekikagaku.66.251

no abstracts in English

New result in the production and decay of an isotope, 113 of the 113th element

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sumita, Takayuki*; Wakabayashi, Yasuo*; Yoneda, Akira*; Tanaka, Kengo*; et al.

Journal of the Physical Society of Japan, 81(10), p.103201_1 - 103201_4, 2012/10

https://doi.org/10.1143/JPSJ.81.103201

An isotope of the 113th element, 113, was produced in a nuclear reaction with a Zn beam on a Bi target. We observed six consecutive decays following the implantation of a heavy particle in nearly the same position in the semiconductor detector, in extremely low background condition. The fifth and sixth decays are fully consistent with the sequential decays of Db and Lr both in decay energies and decay times. This indicates that the present decay chain consisted of 113, Rg (Z = 111), Mt (Z = 109), Bh (Z = 107), Db (Z = 105), and Lr (Z = 103) with firm connections. This result, together with previously reported results from 2004 and 2007, conclusively leads the unambiguous production and identification of the isotope 113, of the 113th element.

Neutron one-quasiparticle states in Fm populated via the decay of No

Asai, Masato; Tsukada, Kazuaki; Haba, Hiromitsu*; Ishii, Yasuo; Ichikawa, Takatoshi*; Toyoshima, Atsushi; Ishii, Tetsuro; Nagame, Yuichiro; Nishinaka, Ichiro; Kojima, Yasuaki*; et al.

Physical Review C, 83(1), p.014315_1 - 014315_12, 2011/01

https://doi.org/10.1103/PhysRevC.83.014315

Excited states in Fm populated via the decay of No are studied in detail through - coincidence and fine structure measurements. Spin-parities and neutron configurations of the excited states in Fm as well as the ground state of No are definitely identified on the basis of deduced internal conversion coefficients, lifetimes of transitions, rotational-band energies built on one-quasiparticle states, and hindrance factors of transitions. It is found that the excitation energy of the 1/2[620] state in =151 isotones increases with the atomic number, especially at 100, while that of the 1/2[631] state decreases at =100. Energy systematics of the one-quasiparticle states in the =151 isotones are discussed in terms of the evolution of nuclear deformation involving the hexadecapole and hexacontatetrapole deformations.

Ac metallofullerene; Toward Ac nanogenerator in fullerene

Akiyama, Kazuhiko*; Haba, Hiromitsu*; Sueki, Keisuke*; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Nagame, Yuichiro; Katada, Motomi*

Chemistry Letters, 38(10), p.978 - 979, 2009/09

https://doi.org/10.1246/cl.2009.978

We report on the successful production of a metallofullerene encapsulating the radioactive tracer Ac and on its electronic properties studied by radiochromatography. Considering the number of -electrons on the fullerene cage estimated from an HPLC retention time on the 5PBB column and the general oxidation state of Ac (+3), a chemical species of the dominant chromatographic peak is suggested to be Ac@C.

A Metallofullerene that encapsulates Ac

Akiyama, Kazuhiko*; Haba, Hiromitsu*; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Sueki, Keisuke*; Nagame, Yuichiro; Katada, Motomi*

Journal of Radioanalytical and Nuclear Chemistry, 280(2), p.329 - 331, 2009/05

https://doi.org/10.1007/s10967-009-0522-8

The properties of a metallofullerene that encapsulates Ac were studied by radio-chromatographic methods. The results of chromatography on a Buckyclutcher column suggest that there are some metallofullerene isomers of AcC. The identical HPLC retention time of the major AcC peak with that of La@C indicates that the structure of one of the AcC isomers is the same as La@C.