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.

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2019

Takeuchi, Ryuji; Onoe, Hironori; Murakami, Hiroaki; Watanabe, Yusuke; Mikake, Shinichiro; Ikeda, Koki; Iyatomi, Yosuke; Nishio, Kazuhisa*; Sasao, Eiji

JAEA-Review 2021-003, 63 Pages, 2021/06

JAEA-Review-2021-003.pdf:12.67MB

The Mizunami Underground Research Laboratory (MIU) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline rock (granite) at Mizunami City, Gifu Prefecture, central Japan. On the occasion of JAEA reformation in FY2014, JAEA identified three remaining important issues on the geoscientific research program based on the synthesized latest results of research and development (R&D): "Development of countermeasure technologies for reducing groundwater inflow", "Development of modeling technologies for mass transport" and "Development of drift backfilling technologies". At the MIU, the R&D are being pursued with a focus on the remaining important issues from FY2015, and satisfactory results have been achieved. Based on this situation, the R&D on the MIU Project were completed at the end of FY2019. In this report, the results of R&D and construction activities of the MIU Project in FY2019 are summarized.

Development of a bunch-width monitor for low-intensity muon beam below a few MeV

Sue, Yuki*; Yotsuzuka, Mai*; Futatsukawa, Kenta*; Hasegawa, Kazuo; Iijima, Toru*; Iinuma, Hiromi*; Inami, Kenji*; Ishida, Katsuhiko*; Kawamura, Naritoshi*; Kitamura, Ryo; et al.

Physical Review Accelerators and Beams (Internet), 23(2), p.022804_1 - 022804_7, 2020/02

https://doi.org/10.1103/PhysRevAccelBeams.23.022804

A destructive monitor to measure the longitudinal bunch width of a low-energy and low-intensity muon beam was developed. This bunch-width monitor (BWM) employed microchannel plates to detect a single muon with high time resolution. In addition, constant-fraction discriminators were adopted to suppress the time-walk effect. The time resolution was measured to be 65 ps in rms using a picosecond-pulsed laser. This resolution satisfied the requirements of the muon linac of the J-PARC E34 experiment. We measured the bunch width of negative-muonium ions accelerated with a radio-frequency quadrupole using the BWM. The bunch width was successfully measured to be 54 11 ns, which is consistent with the simulation.

Bunch size measurement with high time resolution for RF accelerated muon beam

Sue, Yuki*; Iijima, Toru*; Inami, Kenji*; Yotsuzuka, Mai*; Iinuma, Hiromi*; Nakazawa, Yuga*; Otani, Masashi*; Kawamura, Naritoshi*; Shimomura, Koichiro*; Futatsukawa, Kenta*; et al.

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.55 - 60, 2019/07

https://www.pasj.jp/web_publish/pasj2019/proceedings/PDF/WEOI/WEOI05.pdf

The result of bunch size measurement of muon accelerated by RFQ up to 89 keV is presented in this paper. A four-stage muon linac for precise measurement of muon property is under construction in the J-PARC. The demonstration of the first muon RF acceleration with an RFQ linac was conducted and the transverse profile of the accelerated muons was measured in 2017. As one of the remaining issues for the beam diagnostic system, the longitudinal beam profile after the RFQ should be measured to match the profile to the designed acceptance of the subsequent accelerator. For this purpose, the new longitudinal beam monitor using the microchannel plate is under development. The time resolution of the monitor aims to be around 30 to 40 ps corresponding to 1% of a period of an operating frequency of the accelerator, which is 324 MHz. On November 2018, the bunch size of accelerated negative muonium ion of 89 keV with the RFQ was measured using this monitor at the J-PARC MLF. The measured bunch width is ns, which is consistent with the simulation.

Backfilling test in drilling pits as part of Groundwater REcovery Experiment in Tunnel (GREET) Project

Takayasu, Kentaro; Onuki, Kenji*; Kawamoto, Koji*; Takayama, Yusuke; Mikake, Shinichiro; Sato, Toshinori; Onoe, Hironori; Takeuchi, Ryuji

JAEA-Technology 2017-011, 61 Pages, 2017/06

JAEA-Technology-2017-011.pdf:9.15MB

The Groundwater REcovery Experiment in Tunnel (GREET) was put into effect as development of drift backfilling technologies. This test was conducted by making the Closure Test Drift (CTD) recovered with water after carrying out a plug around 40m distance from northern edge face of horizontal tunnel of depth 500m, for the purpose of investigation of recovering process of rock mass and groundwater under the influence of excavation of tunnel. This report presents the efforts of backfilling investigation using bentonite composite soil and execution of backfilling into borehole pits excavated in the CTD which were carried out in fiscal 2014 as a part of GREET, and succeeding observation results inside pits from September 2014 to March 2016.

X-ray absorption spectroscopy and novel electronic properties in heavy fermion compounds YbTZn (T: Rh and Ir)

Honda, Fuminori*; Hirose, Yusuke*; Miyake, Atsushi*; Mizumaki, Masaichiro*; Kawamura, Naomi*; Tsutsui, Satoshi*; Watanuki, Tetsu; Watanabe, Shinji*; Takeuchi, Tetsuya*; Settai, Rikio*; et al.

Journal of Physics; Conference Series, 592(1), p.012021_1 - 012021_5, 2015/03

https://doi.org/10.1088/1742-6596/592/1/012021

no abstracts in English

Unique Fermi surface and emergence of charge density wave in EuGa and EuAl

Nakamura, Ai*; Hiranaka, Yuichi*; Hedo, Masato*; Nakama, Takao*; Miura, Yasunao*; Tsutsumi, Hiroki*; Mori, Akinobu*; Ishida, Kazuhiro*; Mitamura, Katsuya*; Hirose, Yusuke*; et al.

JPS Conference Proceedings (Internet), 3, p.011012_1 - 011012_6, 2014/06

https://doi.org/10.7566/JPSCP.3.011012

Fermi surface and magnetic properties of antiferromagnet EuBi

Nakamura, Ai*; Hiranaka, Yuichi*; Hedo, Masato*; Nakama, Takao*; Tatetsu, Yasutomi*; Maehira, Takahiro*; Miura, Yasunao*; Mori, Akinobu*; Tsutsumi, Hiroki*; Hirose, Yusuke*; et al.

Journal of the Physical Society of Japan, 82(12), p.124708_1 - 124708_6, 2013/12

https://doi.org/10.7566/JPSJ.82.124708

Single crystal growth and various electronic states in Yb-based compounds

Hirose, Yusuke*; Yoshiuchi, Shingo*; Nishimura, Naoto*; Sakaguchi, Junya*; Enoki, Kentaro*; Iwakawa, Ken*; Miura, Yasunao*; Sugiyama, Kiyohiro*; Onuki, Yoshichika; Settai, Rikio*; et al.

Journal of the Korean Physical Society, 62(12), p.1858 - 1861, 2013/06

https://doi.org/10.3938/jkps.62.1858

Fermi surface and superconducting properties of non-centrosymmetric LaNiC

Hirose, Yusuke*; Kishino, Toshihiko*; Sakaguchi, Junya*; Miura, Yasunao*; Honda, Fuminori*; Takeuchi, Tetsuya*; Yamamoto, Etsuji; Haga, Yoshinori; Harima, Hisatomo*; Settai, Rikio*; et al.

Journal of the Physical Society of Japan, 81(11), p.113703_1 - 113703_4, 2012/11

https://doi.org/10.1143/JPSJ.81.113703