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Journal Articles

The Present conditions of the acceleration voltage after the acceleration tube update

Matsuda, Makoto; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro

JAEA-Conf 2018-003, p.126 - 131, 2019/02

no abstracts in English

Journal Articles

First ionization potentials of Fm, Md, No, and Lr; Verification of filling-up of 5f electrons and confirmation of the actinide series

Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Beerwerth, R.*; Kaneya, Yusuke*; Makii, Hiroyuki; Mitsukai, Akina*; Nagame, Yuichiro; Osa, Akihiko; Toyoshima, Atsushi; et al.

Journal of the American Chemical Society, 140(44), p.14609 - 14613, 2018/11

 Times Cited Count:4 Percentile:21.13(Chemistry, Multidisciplinary)

The first ionization potential (IP$$_1$$) yields information on valence electronic structure of an atom. IP$$_1$$ values of heavy actinides beyond einsteinium (Es, Z = 99), however, have not been determined experimentally so far due to the difficulty in obtaining these elements on scales of more than one atom at a time. Recently, we successfully measured IP$$_1$$ of lawrencium (Lr, Z = 103) using a surface ionization method. The result suggests that Lr has a loosely-bound electron in the outermost orbital. In contrast to Lr, nobelium (No, Z = 102) is expected to have the highest IP$$_1$$ among the actinide elements owing to its full-filled 5f and the 7s orbitals. In the present study, we have successfully determined IP$$_1$$ values of No as well as fermium (Fm, Z = 100) and mendelevium (Md, Z = 101) using the surface ionization method. The obtained results indicate that the IP$$_1$$ value of heavy actinoids would increase monotonically with filling electrons up in the 5f orbital like heavy lanthanoids.

Journal Articles

Present status of JAEA-Tokai tandem accelerator

Matsuda, Makoto; Kabumoto, Hiroshi; Tayama, Hidekazu; Nakanoya, Takamitsu; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Ishizaki, Nobuhiro; et al.

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1271 - 1275, 2018/08

The JAEA-Tokai tandem accelerator was operated over a total of 64 days, and delivered 13 different ions to the experiments in the research fields of nuclear physics, nuclear chemistry, atomic physics, solid state physics and radiation effects in material in FY2017. After the vacuum accident occurred in December 2016 the accelerating voltage dropped to 12 MV. In order to remove dust and broken carbon foil in the accelerating tube, all 80 accelerator tubes were removed and rewashed. It took 4 months for cleaning and 2 months for reassembly. Therefore about 10 months were a maintenance period of an accelerator from February 2017. Along with the reconstruction of the accelerating tube, re-alignment of the accelerating tube was carried out. The operation resumed in December 2017 and it was possible to recover the maximum voltage to 17.4 MV without beam and 16.6 MV with beam with periodic conditioning work.

Journal Articles

Present status of JAEA-Tokai tandem accelerator

Kabumoto, Hiroshi; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Matsuda, Makoto; Nakanoya, Takamitsu; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1404 - 1408, 2017/12

The JAEA-Tokai tandem accelerator was operated over a total of 110 days, and delivered 22 different ions to the experiments in the research fields of nuclear physics, nuclear chemistry, atomic physics, solid state physics and radiation effects in material in FY2016. The damaged acceleration tubes by discharge were replaced with the spare tube at the regular maintenance period in March 2016, and the maximum accelerating voltage recovered to the 17 MV. However, an accident of vacuum breaking of all acceleration tubes was occurred in December, and accelerating voltage fell down to under 12 MV. Now, we are doing the maintenance to recover the performance of acceleration voltage. This paper describes the operational status of the accelerators and the major technical developments of our facility.

Journal Articles

First ionization potential of the heaviest actinide lawrencium, element 103

Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Stora, T.*; Sato, Nozomi*; Kaneya, Yusuke; Tsukada, Kazuaki; D$"u$llmann, C. E.*; Eberhardt, K.*; Eliav, E.*; et al.

EPJ Web of Conferences (Internet), 131, p.05001_1 - 05001_6, 2016/12

 Percentile:100

Ionization efficiency in a surface ionization process depends on the first ionization potential of the atom. Based on the dependence, the ionization potential of the atom can be determined. We measured ionization efficiencies of fermium, einsteinium, mendelevium, and lawrencium by using a newly developed gas-jet coupled surface ion-source. The ionization potential of the elements have not been determined so far due to their low production rates and/or their short half-lives. Based on a relationship between the ionization efficiency and the ionization potential obtained via measurements of short-lived lanthanide isotopes, the ionization potentials of these actinide elements have been successfully determined.

Journal Articles

Local fields at nonmagnetic impurity sites in a perovskite $${rm La_{0.7}Ca_{0.3}MnO_3}$$

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

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

 Times Cited Count:1 Percentile:39.82

The magnetic hyperfine field and electric field gradient at the$$^{111}$$Cd($$leftarrow$$ $$^{rm 111m}$$Cd) and $$^{rm 111}$$Cd($$leftarrow$$$$^{rm 111}$$In) probe nuclei introduced in a perovskite manganese oxide $${rm La_{0.7}Ca_{0.3}MnO_{3}}$$ ($$T_C$$ $$sim$$ 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 $$^{111}$$Cd nucleus on the La/Ca A site. This observation suggests that the large magnetic hyperfine field ($$B_{hf}$$ = 6.9 T) measured, in our previous work, at the $$^{140}$$Ce probe nucleus on the A site originates from the contribution of a 4$$f$$ spin oriented by the SMHF from adjacent Mn ions.

Journal Articles

Present status of JAEA-Tokai tandem accelerator and booster

Matsuda, Makoto; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro

Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1413 - 1417, 2016/11

The tandem accelerator was operated over a total of 140 days and delivered 22 different ions to the experiments in the fields of nuclear physics, nuclear chemistry, atomic physics, solid state physics and radiation effects in material. Maximum accelerating voltage is keeping up 18 MV and there was used for ten days on this voltage. However, electric discharge was occurred frequently in December and accelerating voltage fell to 12 MV. The damaged acceleration tubes were replaced with the spare tube at the regular maintenance period in March. The superconducting booster was not operated. This paper describes the operational status of the accelerators and the major technical developments.

Journal Articles

Direct measurement of nanoscale lithium diffusion in solid battery materials using radioactive tracer of $$^{8}$$Li

Ishiyama, Hironobu*; Jeong, S.-C.*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Jung, H. S.*; Miyatake, Hiroari*; Oyaizu, Mitsuhiro*; Osa, Akihiko; Otokawa, Yoshinori; et al.

Nuclear Instruments and Methods in Physics Research B, 376, p.379 - 381, 2016/06

 Times Cited Count:2 Percentile:57.25(Instruments & Instrumentation)

Journal Articles

Present status of JAEA-Tokai tandem accelerator and booster

Matsuda, Makoto; Osa, Akihiko; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; et al.

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.357 - 360, 2015/09

no abstracts in English

Journal Articles

Measurement of the first ionization potential of lawrencium, element 103

Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Stora, T.*; Sato, Nozomi; Kaneya, Yusuke; Tsukada, Kazuaki; D$"u$llmann, Ch. E.*; Eberhardt, K.*; Eliav, E.*; et al.

Nature, 520(7546), p.209 - 211, 2015/04

 Times Cited Count:59 Percentile:1.63(Multidisciplinary Sciences)

Ionization efficiency in a surface ionization process depends on the first ionization potential of the atom. Based on the dependence, the ionization potential of the atom can be determined. We successfully measured ionization efficiencies of lawrencium (Lr, $$Z$$=103) using a gas-jet coupled surface ion-source. The ionization potential of Lr has not been determined owing to its low production rate and its short half-life. Based on a relationship between the ionization efficiency and the ionization potential obtained via measurements of short-lived lanthanide isotopes, the ionization potential of Lr was determined.

Journal Articles

The Failure example of the Tokai tandem accelerator

Matsuda, Makoto; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; et al.

Dai-27-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.142 - 145, 2015/03

no abstracts in English

Journal Articles

Development of a He/CdI$$_{2}$$ gas-jet system coupled to a surface-ionization type ion-source in JAEA-ISOL; towards determination of the first ionization potential of Lr (Z = 103)

Sato, Tetsuya; Asai, Masato; Sato, Nozomi; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro*; Miyashita, Sunao*; Kaneya, Yusuke; Osa, Akihiko; Sch$"a$del, M.; et al.

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1253 - 1257, 2015/02

 Times Cited Count:5 Percentile:43.49(Chemistry, Analytical)

We have developed a surface-ionization ion-source coupled to the He/CdI$$_2$$ gas-jet transport system for the Isotope Separator On-Line (ISOL) at the JAEA tandem accelerator for experimental determination of the first ionization potential of lawrencium (Lr, $$Z = 103$$). We performed to ionize a short-lived Lr isotope and various lanthanide isotopes. We successfully observed mass-separated ions of $$^{256}$$Lr by using our present system at the first time. The first ionization potential of Lr was evaluated based on a correlation between of effective ionization potential and ionization efficiency of short-lived lanthanide isotopes in our system.

Journal Articles

Nanoscale diffusion tracing by radioactive $$^{8}$$Li tracer

Ishiyama, Hironobu*; Jeong, S.-C.*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Miyatake, Hiroari*; Oyaizu, Mitsuhiro*; Katayama, Ichiro*; Osa, Akihiko; Otokawa, Yoshinori; et al.

Japanese Journal of Applied Physics, 53(11), p.110303_1 - 110303_4, 2014/11

 Times Cited Count:3 Percentile:78.29(Physics, Applied)

Journal Articles

Present status of JAEA-Tokai tandem accelerator and booster

Matsuda, Makoto; Osa, Akihiko; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; et al.

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.410 - 413, 2014/10

no abstracts in English

JAEA Reports

Workshop of the JAEA-Tokai tandem accelerator "Heavy Ion Science in Tandem Energy Region"; July 2-3, 2013, Nuclear Science Research Institute, Japan Atomic Energy Agency

Ishii, Tetsuro; Osa, Akihiko; Nishio, Katsuhisa; Asai, Masato; Ishikawa, Norito; Matsuda, Makoto

JAEA-Review 2014-002, 238 Pages, 2014/08

JAEA-Review-2014-002.pdf:149.5MB

The facility of the JAEA-Tokai tandem accelerator has been contributing toward advancing heavy ion science researches in the fields of nuclear physics, nuclear chemistry, production of RI for nuclear medicine, atomic physics, radiation effects, and so on. Due to the 2011 off the Pacific coast of Tohoku Earthquake and all that, situation revolving around the JAEA-Tokai tandem accelerator was greatly-changed. For active discussions of this situation among scientists in the different fields, the workshop "Heavy Ion Science in Tandem Energy Region" was held although there has been no such workshop for many years. The users of the JAEA-Tokai tandem accelerators made presentations of their research achievements in the last few years and reviewed the recent research trend of each fields. This workshop was held at Research building No.1 in Nuclear Research Institute on July 2nd and 3rd in 2013, having 20 oral presentations and 28 posters, and successfully carried out with as many as 60 participants and a lot of serious discussions. This review is the collection of slides of oral presentations.

Journal Articles

Present status of JAEA-Tokai tandem accelerator and booster

Matsuda, Makoto; Osa, Akihiko; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; et al.

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.307 - 309, 2014/06

no abstracts in English

Journal Articles

Performance of a total absorption clover detector for $$Q_{beta}$$ measurements of neutron-rich nuclei far from the $$beta$$-stability line

Hayashi, Hiroaki*; Shibata, Michihiro*; Asai, Masato; Osa, Akihiko; Sato, Tetsuya; Koizumi, Mitsuo; Kimura, Atsushi; Oshima, Masumi*

Nuclear Instruments and Methods in Physics Research A, 747, p.41 - 51, 2014/05

 Times Cited Count:4 Percentile:51.53(Instruments & Instrumentation)

To measure $$beta$$-decay energy $$Q_{beta}$$ of short-lived fission products with good accuracy and high efficiency, we have developed a new total absorption clover detector and demonstrated its performance. Using a large-volume clover-type Ge detector having a through-hole in its center, we could measure total absorption spectra of $$beta$$ + $$gamma$$ rays with extremely high efficiency and high energy resolution, and could determine $$Q_{beta}$$ values with $$pm$$30 keV accuracy. Using this detector, we have determined the $$Q_{beta}$$ values of $$^{166}$$Eu and $$^{165}$$Gd for the first time, and of $$^{160-165}$$Eu and $$^{163}$$Gd with better accuracies. In addition, we have observed a new isomeric state in $$^{163}$$Gd, and determined its half-life and excitation energy.

Journal Articles

In-beam $$gamma$$ spectroscopy of the even-even nucleus $$^{190}$$Pt

Li, G. S.*; Liu, M. L.*; Zhou, X. H.*; Zhang, Y. H.*; Liu, Y. X.*; Zhang, N. T.*; Hua, W.*; Zheng, Y. D.*; Fang, Y. D.*; Guo, S.*; et al.

Physical Review C, 89(5), p.054303_1 - 054303_9, 2014/05

 Times Cited Count:3 Percentile:63.98(Physics, Nuclear)

High-spin states of $$^{190}$$Pt have been reinvestigated using the $$^{176}$$Yb($$^{18}$$O, 4$$n$$) reaction at a beam energy of 88 MeV. The previously known positive parity band associated with the $$nu$$ $$i^{-2}_{13/2}$$ $$nu$$ $$h^{-1}_{9/2}$$ $$nu$$ $$j^{-1}$$ ($$nu j$$ being $$nu p_{3/2}$$ or $$nu f_{5/2}$$) configuration has been revised and extended significantly. A new negative parity band has been established and proposed to be based on the $$nu$$ $$i^{-3}_{13/2}$$ $$nu$$ $$j^{-1}$$ configuration. Possible structure evolution of the yrast line from predominantly vibrational to rotational with increasing spin is discussed with the help of E$$_gamma$$ over spin curves. Additionally, calculations of Total Routhian surfaces have been performed to investigate the band properties.

Journal Articles

Present status of JAEA-Tokai tandem accelerator and booster

Matsuda, Makoto; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; et al.

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.362 - 366, 2013/08

no abstracts in English

Journal Articles

Signature splitting inversion and backbending in $$^{80}$$Rb

He, C.*; Shen, S.*; Wen, S.*; Zhu, L.*; Wu, X.*; Li, G.*; Zhao, Y.*; Yan, Y.*; Bai, Z.*; Wu, Y.*; et al.

Physical Review C, 87(3), p.034320_1 - 034320_10, 2013/03

 Times Cited Count:2 Percentile:74.33(Physics, Nuclear)

183 (Records 1-20 displayed on this page)