Proceedings of the 2020 Symposium on Nuclear Data; November 26-27, 2020, RIKEN Nishina Center, RIKEN Wako Campus, Wako, Saitama, Japan

Imai, Nobuaki*; Otsu, Hideaki*

JAEA-Conf 2021-001, 236 Pages, 2022/03

JAEA-Conf-2021-001.pdf:48.06MB

The 2020 Symposium on Nuclear Data was held on-site at RIBF Conference Hall in RIKEN Wako campus on November 26 to 27, 2020, combined with on-line connection conference. The symposium was organized by the Nuclear Data Division of the Atomic Energy Society of Japan (AESJ) in cooperation with Sigma Investigative Advisory Committee of AESJ, Nuclear Science and Engineering Center of Japan Atomic Energy Agency (JAEA), RIKEN Nishina Center, Center for Nuclear Study, The University of Tokyo (CNS), KEK Wako Nuclear Science Center (WNSC), School of Science, The University of Tokyo. In the symposium, six sessions were proposed and held: "Reactor theory and experiments" as a tutorial, "Accelerator Facilities and Nuclear Data", "Deep/Machine Learning and Nuclear Physics, Application to Nuclear Data", "Nuclear Medicine and Nuclear Pharmacy", "Fission, Heavy Ion Nuclear Spectroscopy", and "Nuclear Reaction Data" as lecture and discussion sessions. In addition, recent research progress on experiments, nuclear theory, evaluation, benchmark and applications were presented in the poster session. The total number of participants was 119, of which 62 were on-site participants. Each oral and poster presentation was followed by an active question and answer session. This report consists of total 40 papers including 15 oral and 25 poster presentations.

Transverse asymmetry of rays from neutron-induced compound states of La

Yamamoto, Tomoki*; Okudaira, Takuya; Endo, Shunsuke; Fujioka, Hiroyuki*; Hirota, Katsuya*; Ino, Takashi*; Ishizaki, Kohei*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; et al.

Physical Review C, 101(6), p.064624_1 - 064624_8, 2020/06

https://doi.org/10.1103/PhysRevC.101.064624

Effects of multichance fission on isotope dependence of fission fragment mass distributions at high energies

Tanaka, Shoya; Aritomo, Yoshihiro*; Miyamoto, Yuya*; Hirose, Kentaro; Nishio, Katsuhisa

Physical Review C, 100(6), p.064605_1 - 064605_6, 2019/12

https://doi.org/10.1103/PhysRevC.100.064605

Fission fragment mass distributions of U, Np, and Pu are studied using the Langevin approach in the widely excitation energy range as = 15-55 MeV. In the present calculation, neutron emission before fission, so called multichance fission, was introduced. The calculated results well demonstrated the experimental data, which shows the double-peak structure up to the highest excitation energies and the clear dependence on the initial fissioning nuclides. The trend is nicely correlated with the neutron binding energy of the compound nucleus that dominates the neutron emission probability before fission.

Energy of the Th nuclear clock isomer determined by absolute -ray energy difference

Yamaguchi, Atsushi*; Muramatsu, Haruka*; Hayashi, Tasuku*; Yuasa, Naoki*; Nakamura, Keisuke; Takimoto, Misaki; Haba, Hiromitsu*; Konashi, Kenji*; Watanabe, Makoto*; Kikunaga, Hidetoshi*; et al.

Physical Review Letters, 123(22), p.222501_1 - 222501_6, 2019/11

https://doi.org/10.1103/PhysRevLett.123.222501

Inverse odd-even staggering in nuclear charge radii and possible octupole collectivity in At revealed by in-source laser spectroscopy

Barzakh, A. E.*; Cubiss, J. G.*; Andreyev, A. N.; Seliverstov, M. D.*; Andel, B.*; Antalic, S.*; Ascher, P.*; Atanasov, D.*; Beck, D.*; Biero, J.*; et al.

Physical Review C, 99(5), p.054317_1 - 054317_9, 2019/05

https://doi.org/10.1103/PhysRevC.99.054317

Charge identification of low-energy particles for double-strangeness nuclei in nuclear emulsion

Kimbara, Shinji*; Ekawa, Hiroyuki; Hayakawa, Shuhei; Yoshida, Junya; 12 of others*

Progress of Theoretical and Experimental Physics (Internet), 2019(1), p.011H01_1 - 011H01_9, 2019/01

https://doi.org/10.1093/ptep/pty137

A development has been achieved in the identification method of the charges 1 to 5 of nuclides from the decay of double hypernuclei to be uniquely recognized by their nuclear species. The method is basically the measurement of track volume by the widths, depths, and angles of tracks of exposed nuclei of H, He, Li, Be, and B in nuclear emulsion at Riken Projectile-fragment Separator of RIKEN Radioactive Isotope Beam Factory. After their calibration by particles, we obtained a quadric function to present a unified recognition of tracks with volume ratios of five nuclei to the particles. The function in the emulsion has been applied to a candidate event of a hypernucleus for identification of the production and decay processes. We succeeded in recognizing a daughter nuclear fragment of a single- hypernucleus as He with a likelihood ratio of 0.9; the process was then uniquely identified as + N Be + He + .

Nuclear quantum effects of light and heavy water studied by all-electron first principles path integral simulations

Machida, Masahiko; Kato, Koichiro*; Shiga, Motoyuki

Journal of Chemical Physics, 148(10), p.102324_1 - 102324_11, 2018/03

AA2017-0553.pdf:4.95MB

https://doi.org/10.1063/1.5000091

The isotopologs of liquid water, HO, DO, and TO, are studied systematically by first principles PIMD simulations, in which the whole entity of the electrons and nuclei are treated quantum mechanically. The simulation results are in reasonable agreement with available experimental data on isotope effects, in particular, on the peak shift in the radial distributions of HO and DO and the shift in the evaporation energies. It is found that, due to differences in nuclear quantum effects, the H atoms in the OH bonds more easily access the dissociative region up to the hydrogen bond center than the D (T) atoms in the OD (OT) bonds. The accuracy and limitation in the use of the current density-functional-theory-based first principles PIMD simulations are also discussed. It is argued that the inclusion of the dispersion correction or relevant improvements in the density functionals are required for the quantitative estimation of isotope effects.

The Laser and optical system for the RIBF-PALIS experiment

Sonoda, Tetsu*; Iimura, Hideki; Reponen, M.*; Wada, Michiharu*; Katayama, Ichiro*; Sonnenschein, V.*; Takamatsu, Takahide*; Tomita, Hideki*; Kojima, Takao*

Nuclear Instruments and Methods in Physics Research A, 877, p.118 - 123, 2018/01

https://doi.org/10.1016/j.nima.2017.09.055

In order to produce low-energy RI beams at RIKEN RIBF, a laser ion source, PALIS, is under construction. This ion source is based on resonance ionization of RI atoms captured in Ar gas. Because the ion source is located 70m away from lasers, we have developed an optical system for laser beam transport. This system can be controlled remotely when the ion source is not accessible because of high radiation level. The position of laser beam after transport is reasonably stable, and the transport efficiency is about 50%.

Local fields at nonmagnetic impurity sites in a perovskite

Sato, Wataru*; Komatsuda, Sayaka*; Osa, Akihiko; Sato, Tetsuya; Okubo, Yoshitaka*

Hyperfine Interactions, 237(1), p.113_1 - 113_6, 2016/12

https://doi.org/10.1007/s10751-016-1325-2

The magnetic hyperfine field and electric field gradient at theCd( Cd) and Cd(In) probe nuclei introduced in a perovskite manganese oxide ( 250 K) were measured for the study of the local magnetism and structure by means of time-differential perturbed angular correlation spectroscopy. In the ferromagnetic phase at 77 K, a very slight supertransferred magnetic hyperfine field (SMHF) ( 0.014 T) combined with a well-defined electric field gradient was observed at the nonmagnetic Cd nucleus on the La/Ca A site. This observation suggests that the large magnetic hyperfine field ( = 6.9 T) measured, in our previous work, at the Ce probe nucleus on the A site originates from the contribution of a 4 spin oriented by the SMHF from adjacent Mn ions.

Production and separation of astatine isotopes in the Li + Pb reaction

Nishinaka, Ichiro; Yokoyama, Akihiko*; Washiyama, Koshin*; Maeda, Eita*; Watanabe, Shigeki; Hashimoto, Kazuyuki; Ishioka, Noriko; Makii, Hiroyuki; Toyoshima, Atsushi; Yamada, Norihiro*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 304(3), p.1077 - 1083, 2015/06

https://doi.org/10.1007/s10967-015-3975-y

Production cross sections of astatine isotopes At in the 29-57 MeV Li induced reaction with Pb target have been measured by - and -ray spectrometry. Excitation functions of production cross sections have been compared with a statistical model calculation to study the reaction mechanism of Li + Pb. Considerably small experimental cross sections of At and At compared with the calculation were clearly observed at incident energies higher than 44 MeV, indicating that the effects of breakup reaction play a role. A chemical separation of astatine from an irradiated lead target has been studied with a dry-distillation method. A complementary way to produce astatine isotopes has been developed.