Quantum critical behavior of the hyperkagome magnet MnCoSi

Yamauchi, Hiroki; Sari, D. P.*; Yasui, Yukio*; Sakakura, Terutoshi*; Kimura, Hiroyuki*; Nakao, Akiko*; Ohara, Takashi; Honda, Takashi*; Kodama, Katsuaki; Igawa, Naoki; et al.

Physical Review Research (Internet), 6(1), p.013144_1 - 013144_9, 2024/02

https://doi.org/10.1103/PhysRevResearch.6.013144

Analysis of deposits inside the reactor at Fukushima Daiichi Nuclear Power Station in JFY2021; The Subsidy program of "Project of Decommissioning and Contaminated Water Management (Development of Analysis and Estimation Technology for Characterization of Fuel Debris)" starting FY2021

Ikeuchi, Hirotomo; Sasaki, Shinji; Onishi, Takashi; Nakayoshi, Akira; Arai, Yoichi; Sato, Takumi; Ohgi, Hiroshi; Sekio, Yoshihiro; Yamaguchi, Yukako; Morishita, Kazuki; et al.

JAEA-Data/Code 2023-005, 418 Pages, 2023/12

JAEA-Data-Code-2023-005-01.pdf:24.59MB
JAEA-Data-Code-2023-005-02.pdf:32.18MB

For safe and steady decommissioning of Tokyo Electric Power Company Holdings' Fukushima Daiichi Nuclear Power Station (1F), information concerning composition and physical/chemical properties of fuel debris generated in the reactors should be estimated and provided to other projects conducting the decommissioning work including the retrieval of fuel debris and the subsequent storage. For this purpose, in FY2021, samples of contaminants (the wiped smear samples and the deposits) obtained through the internal investigation of the 1F Unit 2 were analyzed to clarify the components and to characterize the micro-particles containing uranium originated from fuel (U-bearing particles) in detail. This report summarized the results of analyses performed in FY2021, including the microscopic analysis by SEM and TEM, radiation analysis, and elemental analysis by ICP-MS, as a database for evaluating the main features of each sample and the probable formation mechanism of the U-bearing particles.

Estimation of the activity median aerodynamic diameter of plutonium particles using image analysis

Takasaki, Koji; Yasumune, Takashi; Yamaguchi, Yukako; Hashimoto, Makoto; Maeda, Koji; Kato, Masato

Journal of Nuclear Science and Technology, 60(11), p.1437 - 1446, 2023/11

https://doi.org/10.1080/00223131.2023.2196969

The aerodynamic radioactive median diameter (AMAD) is necessary information to assess the internal exposure. On June 6, 2017, at a plutonium handling facility in Oarai site of Japan Atomic Energy Agency (JAEA), during the inspection work of a storage container that contains nuclear fuel materials, accidental contamination occurred and five workers inhaled radioactive materials including plutonium. Some smear papers and an air sampling filter were measured with the imaging plate, and we conservatively estimated minimum AMADs for two cases, plutonium nitrate and plutonium dioxide. As a result of AMAD estimation, even excluding a giant particle of a smear sample, the minimum AMADs of plutonium nitrate from smear papers were 4.3 - 11.3 m and those of plutonium dioxide were 5.6 - 14.1 m. Also, the minimum AMAD of plutonium nitrate from an air sampling filter was 3.0 m and that of plutonium dioxide was 3.9 m.

Level structures of Ca cast doubt on a doubly magic Ca

Chen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; Tsunoda, Yusuke*; Otsuka, Takaharu*; Chazono, Yoshiki*; Hagen, G.*; Holt, J. D.*; et al.

Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08

https://doi.org/10.1016/j.physletb.2023.138025

Gamma decays were observed in Ca and Ca following quasi-free one-proton knockout reactions from Sc. For Ca, a ray transition was measured to be 1456(12) keV, while for Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the decays. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the and orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic Ca and potentially drives the dripline of Ca isotopes to Ca or even beyond.

Reaction of Np, Am, and Cm ions with CO and O in a reaction cell in triple quadrupole inductively coupled plasma mass spectrometry

Kazama, Hiroyuki; Konashi, Kenji*; Suzuki, Tatsuya*; Koyama, Shinichi; Maeda, Koji; Sekio, Yoshihiro; Onishi, Takashi; Abe, Chikage*; Shikamori, Yasuyuki*; Nagai, Yasuyoshi*

Journal of Analytical Atomic Spectrometry, 38(8), p.1676 - 1681, 2023/07

https://doi.org/10.1039/D3JA00136A

Quasielastic neutron scattering probing H dynamics in the H conductors LaHO

Tamatsukuri, Hiromu; Fukui, Keiga*; Iimura, Soshi*; Honda, Takashi*; Tada, Tomofumi*; Murakami, Yoichi*; Yamaura, Junichi*; Kuramoto, Yoshio*; Sagayama, Hajime*; Yamada, Takeshi*; et al.

Physical Review B, 107(18), p.184114_1 - 184114_8, 2023/05

https://doi.org/10.1103/PhysRevB.107.184114

Fact-finding survey on the competencies and literacy of radiological technologists regarding radiation disasters

Arai, Tomohiro*; Murata, Sho*; Watanabe, Yuichi*; Ishihara, Toshihiro*; Fukamizu, Yoshiya*; Takeda, Satoshi*; Ebata, Kiyokadzu*; Watanabe, Yuki; Takashima, Yoshio*; Kaneko, Junichi*

Journal of X-Ray Science and Technology, 31(2), p.237 - 245, 2023/03

https://doi.org/10.3233/XST-221341

Radiological technologists have received specialized education about radiation and serve as risk communicators who aim to lessen patients' anxiety about radiation exposure, in addition to performing radiological examinations in routine clinical practice. Also, Radiological technologists across Japan were dispatched to the affected area to conduct an essential procedure-screening the belongings and body surfaces of evacuees for contamination at the nuclear disaster at the Fukushima Daiichi Nuclear Power Plant operated by Tokyo Electric Power Company in March 2011. In this study, we conducted a fact-finding survey on knowledge and awareness of radiation disasters among radiological technologists at National Hospital Organization facilities in Japan to reveal their literacy and competencies regarding radiation disasters. Also, we compared the knowledge and awareness of radiation disasters among Japanese radiological technologists between nuclear power station areas and non-nuclear power station areas and discuss ideal human resource development for radiological technologists to be ready to serve during a radiation disaster.

Nonlinear magnon polaritons

Lee, O.*; Yamamoto, Kei; Umeda, Maki; Zollitsch, C. W.*; Elyasi, M.*; Kikkawa, Takashi*; Saito, Eiji; Bauer, G. E. W.*; Kurebayashi, Hidekazu*

Physical Review Letters, 130(4), p.046703_1 - 046703_6, 2023/01

https://doi.org/10.1103/PhysRevLett.130.046703

Extended neutron orbital and the shell closure in Ca

Enciu, M.*; Liu, H. N.*; Obertelli, A.*; Doornenbal, P.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; et al.

Physical Review Letters, 129(26), p.262501_1 - 262501_7, 2022/12

https://doi.org/10.1103/PhysRevLett.129.262501

The one-neutron knockout from Ca was performed at 230 MeV/nucleon combined with prompt spectroscopy. The momentum distributions corresponding to the removal of and neutrons were measured. The cross sections are consistent with a shell closure at the neutron number , found as strong as at and in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron and orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.

Hydrogen vibration excitations of ZrH and TiH up to 21 GPa by incoherent inelastic neutron scattering

Hattori, Takanori; Nakamura, Mitsutaka; Iida, Kazuki*; Machida, Akihiko*; Sano, Asami; Machida, Shinichi*; Arima, Hiroshi*; Oshita, Hidetoshi*; Honda, Takashi*; Ikeda, Kazutaka*; et al.

Physical Review B, 106(13), p.134309_1 - 134309_9, 2022/10

https://doi.org/10.1103/PhysRevB.106.134309

Hydrogen vibration excitations of fluorite-type ZrH and TiH were investigated up to 21 GPa and 4 GPa, respectively, by incoherent inelastic neutron scattering experiments. The first excitation energies increased with pressure, as described by the equations (meV) = 141.4(2) + 1.02(2)(GPa) and (meV) = 149.4(1) + 1.21(8)(GPa) for ZrH and TiH, respectively. Coupling with pressure dependence of lattice parameters, the relations between metal-hydrogen distance () and are found to be well described by the equations (meV) = 1.62(9) 10 ((meV) = 1.47(21) 10 (AA), respectively. The slopes of these curves are much steep compared to the previously reported trend in various fluorite-type metal hydrides at ambient pressure. The hydrogen wave function spreading showed that the local potential field for a hydrogen atom shrinks more intensively than the tetrahedral site. These behavior is likely caused by the rigid metal ion core and the resulting confinement of the hydrogen atom in the narrower potential field at high pressures.