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Tanaka, Taiki*; Narikiyo, Yoshihiro*; Morita, Kosuke*; Fujita, Kunihiro*; Kaji, Daiya*; Morimoto, Koji*; Yamaki, Sayaka*; Wakabayashi, Yasuo*; Tanaka, Kengo*; Takeyama, Mirei*; et al.
Journal of the Physical Society of Japan, 87(1), p.014201_1 - 014201_9, 2018/01
Times Cited Count:18 Percentile:73.84(Physics, Multidisciplinary)Excitation functions of quasielastic scattering cross sections for the Ca + Pb, Ti + Pb, and Ca + Cm reactions were successfully measured by using the gas-filled recoil-ion separator GARIS. Fusion barrier distributions were extracted from these data, and compared with the coupled-channels calculations. It was found that the peak energies of the barrier distributions for the Ca + Pb and Ti + Pb systems coincide with those of the 2n evaporation channel cross sections for the systems, while that of the Ca + Cm is located slightly below the 4n evaporation ones. This results provide us helpful information to predict the optimum beam energy to synthesize superheavy nuclei.
Ariga, Hirotake*; Katori, Taku*; Yoshihara, Ryohei*; Hase, Yoshihiro; Nozawa, Shigeki; Narumi, Issei; Iuchi, Satoshi*; Kobayashi, Masatomo*; Tezuka, Kenji*; Sakata, Yoichi*; et al.
Plant Signaling & Behavior (Internet), 8(7), p.e24779_1 - e24779_5, 2013/07
Based on analysis of the salinity tolerance among 354 accessions, some accessions showed greater salt shock tolerance compared with a reference accession, Col-0 on a typical assay with drastic change in NaCl concentration from 0 mM to 225 mM. On the other hand, several accessions including Zu-0 exhibited marked acquired salt tolerance, which is induced after exposure to moderate salt stress (salt acclimation ability). It is likely that Arabidopsis plants have at least two types of tolerance abilities, salt shock tolerance and salt acclimation. To dissect the salt tolerance mechanisms of the salt tolerant accessions, we isolated a salt-sensitive mutant from ion beam-mutagenized Zu-0 seedlings. The mutant showed severe growth inhibition under salt shock stress due to a single base deletion in SOS1 gene as well-known salt shock tolerance gene, even more salt sensitive than Col-0. Nevertheless, the mutant was able to survive on the salt acclimation with 100 mM NaCl for 7 days followed with 750 mM sorbitol for 20 days (salt acclimation assay) as well as the Zu-0 wild type, whereas Col-0 showed apparent chlorosis under the condition. We propose that a gene for salt acclimation ability is different from a gene for salt shock tolerance and plays an important role in acquisition for marked salt- or osmotic tolerance.
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
Times Cited Count:167 Percentile:97.29(Physics, Multidisciplinary)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.
Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi*; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.
Journal of the Physical Society of Japan, 78(6), p.064201_1 - 064201_6, 2009/06
Times Cited Count:30 Percentile:78.22(Physics, Multidisciplinary)Decay properties of an isotope Bh and its daughter nucleus Db produced by the Cm(Na,5) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. Bh was clearly identified from the correlation of the known nuclide, Db. The obtained decay properties of Bh and Db are consistent with those observed in the 113 chain, which provided further confirmation of the discovery of 113.
Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kudo, Hisaaki*; et al.
RIKEN Accelerator Progress Report, Vol.42, P. 15, 2009/00
In 2003-2007, we had performed an experiment to synthesize an element 113 by a Bi Zn reaction using a gas-filled recoil ion separator (GARIS) at RIKEN Nishina-Center. In a total of 241 days of net irradiation time experiment, two decay chains were observed and assigned from an isotope 113. The cross section of the Bi(Zn,n)113 reaction was determined to be 31 fb at that time. In order to increase the statistics of the decay property, we continued to produce more decay chains. The experiment was carried out from January 7 to March 31, 2008. The experimental conditions were identical to those used in the previous experiment. Zn ion beam of 353 MeV was extracted from RILAC. The net irradiation time was 83 days and the total dose of Zn was 2.28. In the present expriment any candidate of 113 was not observed. Then combining the results of the present and previous experiments, the production cross section of 113 was determined to be 22 fb.
Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kudo, Hisaaki*; et al.
Journal of the Physical Society of Japan, 76(4), p.043201_1 - 043201_5, 2007/04
Times Cited Count:151 Percentile:95.99(Physics, Multidisciplinary)The production and decay of 112 has been investigated using a gas-filled recoil ion separator in irradiations of Pb targets with Zn beam at 349.5 MeV. We have observed two -decay chains that can be assigned to subsequent decays from 112 produced in the 208 Pb(Zn,n) reaction. After emitting four consecutive -particles, the both chains ended by spontaneous fission decays of Rf and decay energies and decay times of the both chains obtained in the present work agree well with those reported by a group at Gesellschaft fr Schwerionenforschung (GSI), Germany. The present result gives the first clear confirmation of the discovery of 112 and its -decay products Ds reported previously.
Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kikunaga, Hidetoshi*; et al.
Journal of the Physical Society of Japan, 76(4), p.045001_1 - 045001_2, 2007/04
Times Cited Count:199 Percentile:97.41(Physics, Multidisciplinary)The production and decay of 113 has been investigated using a gas-filled recoil ion separator in irradiations of Bi targets with Zn beam at 353 MeV. We have observed one -decay chain that can be assigned to subsequent decays from 113 produced in the Bi(Zn,n) reaction. After emitting four consecutive -particles, the both chains ended by spontaneous fission decays of Db and decay energies and decay times of the both chains obtained in the present work agree well with those reported by our group in 2004. The present result gives the first clear confirmation of the discovery of 113 and its -decay products Rg reported previously.
Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Kanungo, R.*; Katori, Kenji*; Kikunaga, Hidetoshi*; et al.
AIP Conference Proceedings 891, p.3 - 9, 2007/03
A series of experiments studying the productions and their decays of the heaviest elements have been performed by using a gas-filled recoil separator GARIS at RIKEN. Results on the isotope of the 112th element, 112, and on that of the 113th element, 113, are reviewed. Two decay chains which are assigned to be ones originating from the isotope 112 were observed in the Pb(Zn, n) reaction. The results provide a confirmation of the production and decay of the isotope 112 reported by a research group at GSI, Germany, produced via the same reaction by using a velocity filter. Two decay chains, both consisted of four consecutive alpha decays followed by a spontaneous fission, were observed also in the reaction Bi(Zn, n). Those are assigned to be the convincing candidate events of the isotope of the 113th element, 113, and its daughter nuclei. Rg, Mt, Bh, and Db.
Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Kanungo, R.*; Katori, Kenji*; Koura, Hiroyuki; et al.
Journal of the Physical Society of Japan, 73(10), p.2593 - 2596, 2004/10
Times Cited Count:487 Percentile:99.21(Physics, Multidisciplinary)The isotope of the 113th element, 113, and its daughter nuclei, 111 and Mt, were obserbed, for the first time, in the Bi + Zn reaction at a beam energy of 349.1 MeV with a total dose of 1.610. The production cross section of 113 is deduced to be fb ( cm).
Inoue, Kazuhiko; Katori, Kenji*
JAERI 1041, 16 Pages, 1962/12
no abstracts in English
Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.
no journal, ,
A nuclide, Bh, is the great-grand-daughter of 113 that is produced in the Bi + Zn reaction. The identification was based on a genetic link to the known daughter nucleus Db by alpha-decays. The main purpose of this work is to provide further confirmation of the production and identification of the isotope 113. As a present result, a state in Bh, which decays by an alpha emission with the energies ranging from 9.05 to 9.23 MeV, feeds a state in Db, which decays by alpha emission and by SF with a previously known half-life. The result provided a further confirmation of the production and identification of the isotope of the 113th element, 113, studied by a research group at RIKEN.
Hanamuro, Takahiro; Yasue, Kenichi; Shibata, Kenji; Umeda, Koji; Takatori, Ryoichi*
no journal, ,
Petrographical and geochemical approaches were adopted by samples of the Inagawa Granite and Naegi-Agematsu Granite, distributed along upper river basin of Toki River. And gravel from upper layer of these rock bodies were investigated for identification of granitic rock bodies. Petrographic feature of these rock bodies are distinguished by hornblende or muscovite contents. Major element analyses of biotites by EPMA showed the samples from the Naegi-Agematsu Granite were rich in Fe relative to those from the Inagawa Granite. By using this method, the gravel from upper layer of these rock bodies is suggested to be from the Naegi-Agematsu Granite area. Therefore, chemical composition of biotite suggests good indicator for hinterland analysis in this case.
Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.
no journal, ,
no abstracts in English
Sumita, Takayuki*; Morimoto, Koji*; Kaji, Daiya*; Ozeki, Kazutaka*; Katori, Kenji*; Sakai, Ryutaro*; Hasebe, Hiroo*; Haba, Hiromitsu*; Yoneda, Akira*; Yoshida, Atsushi*; et al.
no journal, ,
The decay property of Cn (atomic number, ) produced in the Pb(Zn, ) reaction was studied. The experiment was performed using the gas-filled recoil ion separator (GARIS) at the RIKEN liner accelerator facility (RILAC). The Pb target with about 630 g/cm thickness was bombarded with 347.5, 351.5, and 355.5 MeV Zn beam. At the beam energy of 351.5 MeV, we observed one -decay chain from Cn. The -particle energy of Cn was MeV and its lifetime was measured to be 0.370 ms. Including our previous result of the Cn production in 2004, the cross section of the Pb(Zn, ) reaction is deduced to be pb.
Hanamuro, Takahiro; Takatori, Ryoichi; Yasue, Kenichi; Shibata, Kenji; Umeda, Koji
no journal, ,
no abstracts in English
Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.
no journal, ,
We performed the experiment to synthesize an isotope of the element 113 produced by a Bi(Zn,n)113 reaction using a gas-filled recoil ion separator (GARIS) at RIKEN. Two decay chains were observed, and assigned to those originating from an isotope 113. Both chains were connected into the previously known decays of Bh and Db via previously unknown decays of 113, Rg, and Mt. Although the Bh was known nuclide, a number of atoms reported so far was limited. In order to study more precise decay property of the Bh, we performed the direct production of Bh by the Cm(Na,5n)Bh reaction. In this experiment, the Bh was clearly identified from the correlation of the nuclide, Db. The obtained decay properties of Bh and Db are consistent with those observed in the 113 chain, which provided further confirmation of the discovery of 113.