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Kaji, Daiya*; Morimoto, Koji*; Haba, Hiromitsu*; Ideguchi, Eiji*; Koura, Hiroyuki; Morita, Kosuke*
Journal of the Physical Society of Japan, 85(1), p.015002_1 - 015002_2, 2016/01
Times Cited Count:9 Percentile:55.25(Physics, Multidisciplinary)A neutron deficient berkelium isotope of Bk produced via the Au(Ar, 3n) reaction and the daughter product of Am were newly identified. Alpha-decay energies of eleven Bk were found in 7.62 - 7.96 MeV, and six fission events correlated with -decay of Bk were observed. The half-lives of Bk and Am were determined to be 19 s and 32 s, respectively. The Cm followed by -decay of Bk was also identified.
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:97.31(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.
Sato, Nozomi; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Kaji, Daiya*; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Ozeki, Kazutaka*; Sumita, Takayuki*; Yoneda, Akira*; et al.
Journal of the Physical Society of Japan, 80(9), p.094201_1 - 094201_7, 2011/09
Times Cited Count:15 Percentile:65.21(Physics, Multidisciplinary)Decay properties of Hs and Hs produced in the Pb(Fe, ) [=1, 2] reactions were studied using a gas-filled recoil ion separator at the linear accelerator facility of RIKEN. A total of 6 decay chains were assigned to Hs. Cross sections for the Hs production in the Pb(Fe,) and Pb(Fe,) reactions were measured to be pb and pb, respectively. The isotope Hs decayed with a half-life of ms by -particle emission and spontaneous fission. The -particle energy of Hs was observed at 10.610.04 and 10.800.08 MeV. The spontaneous fission branch of Hs was found to be .
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:78.29(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.
Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Ozeki, Kazutaka*; Haba, Hiromitsu*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; et al.
Journal of the Physical Society of Japan, 78(3), p.035003_1 - 035003_2, 2009/03
A new hassium isotopes Hs is directly produced for the first time. The experiment was performed at the linear accelerator (RILAC) facility in RIKEN (the Institute of Physical and Chemical Research) from Jun. 19 to 25. In the 25-h irradiation of Fe on Pb and 46-h irradiation of Fe on Pb, 8 decay chains and 1 decay chain, respectively, were observed. All decay chains were assigned to subsequent decays from Hs. The half-life of Hs is 0.60 ms. In this experiment, the total beam dose was ions for Fe and ions for Fe. The production cross section corresponding to 8 decay events and 1 decay chain was deduced to be 21 pb and 1.6 pb by assuming that the transmission of the system is 80%.
Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Ozeki, Kazutaka*; Haba, Hiromitsu*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; et al.
Journal of the Physical Society of Japan, 78(3), p.035003_1 - 035003_2, 2009/03
Times Cited Count:3 Percentile:26.24(Physics, Multidisciplinary)A new neutron deficient hassium (=108) isotope of Hs was identified via two different reactions of Pb(Fe,n) and Pb(Fe,n) by using a gas-filled recoil separator GARIS at June 2008. During the 25-h irradiation of Pb with the Fe beam and 46-h irradiation of Pb with the Fe beam, 8 decay chains and 1 decay chain, respectively, have been observed. The half-life of Hs is 0.60 ms. In this experiment, the total beam doses of the Fe and Fe was 4.110 ions and 6.210 ions, respectively. The production cross sections corresponding to the 8 decay chains and 1 decay chain have been deduced to be 21 pb and 1.6 pb by assuming the transmission of the system to be 80%.
Sato, Nozomi*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Kaji, Daiya*; Koura, Hiroyuki; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Ozawa, Akira*; et al.
RIKEN Accelerator Progress Report, Vol.42, P. 16, 2009/00
New Decay Properties of Hs and its -decay daughter nuclei were studied by using reactions of Pb(Fe,2n) and Pb(Fe,n) by using a gas-filled recoil ion separator, GARIS at RIKEN. We observed three correlated events in irradiation of Fe on Pb, and eight events in irradiation of Fe on Pb. A half-life was deduced to be 0.90. We assigned these eleven events to be the decays of Hs. We found different decay-chain events of Hs from a previous report. One is a long-lived -decay of Sg with 180ms of half-life. Another is a long-lived -decay of Rf with 10.4s of half-life. For Sg and Rf, the decay of such a long-lived state have not been reported. These are the first observations of isomerism in Sg and Rf.
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:95.96(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:97.42(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:99.22(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).
; Deguchi, Morimoto; Kobayashi, Hideo; ; ; Asano, Takashi
Kaku Busshitsu Kanri Senta Nyusu, 26(8), 0 Pages, 1997/08
None
; Deguchi, Morimoto*; Hirabayashi, F.*; *; *
PNC TN841 84-14VOL3, 1663 Pages, 1984/03
no abstracts in English
; Deguchi, Morimoto*; Hirabayashi, F.*; *; *
PNC TN841 84-14VOL2, 210 Pages, 1984/03
no abstracts in English
; Deguchi, Morimoto*; Hirabayashi, F.*; *; *
PNC TN841 84-14VOL1, 1367 Pages, 1984/03
no abstracts in English