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Yamaguchi, Takayuki*; Koura, Hiroyuki; Litvinov, Yu. A.*; Wang, M.*
Progress in Particle and Nuclear Physics, 120, p.103882_1 - 103882_98, 2021/09
Times Cited Count：25 Percentile：79.69(Physics, Nuclear)Nagae, Daisuke*; Abe, Yasushi*; Okada, Shunsuke*; Omika, Shuichiro*; Wakayama, Kiyoshi*; Hosoi, Shun*; Suzuki, Shinji*; Moriguchi, Tetsuro*; Amano, Masamichi*; Kamioka, Daiki*; et al.
Nuclear Instruments and Methods in Physics Research A, 986, p.164713_1 - 164713_7, 2021/01
Times Cited Count：5 Percentile：65.59(Instruments & Instrumentation)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：74.47(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.
Ca + Cm 
Lv
at RIKEN-GARISKaji, Daiya*; Morita, Kosuke*; Morimoto, Koji*; Haba, Hiromitsu*; Asai, Masato; Fujita, Kunihiro*; Gan, Z.*; Geissel, H.*; Hasebe, Hiroo*; Hofmann, S.*; et al.
Journal of the Physical Society of Japan, 86(3), p.034201_1 - 034201_7, 2017/03
Times Cited Count：28 Percentile：81.43(Physics, Multidisciplinary)The fusion reaction of Ca + Cm Lv was studied using the gas-filled recoil-ion separator GARIS at RIKEN. A total of seven 
and spontaneous-fission decay chains were observed, which would originate from the reaction products of the element 116, 
Lv and 
Lv. Decay properties observed in the chains are in good agreement with the previously published ones. However, one of the chains showed a discrepancy, indicating the new spontaneous-fission branch in 
Cn or the production of the new isotope 
Lv.
Hase, Takayuki*; Otagaki, Tatsuya*; Yamaguchi, Masatake; Ikeo, Naoko*; Mukai, Toshiji*
Acta Materialia, 104, p.283 - 294, 2016/02
Times Cited Count：47 Percentile：89.33(Materials Science, Multidisciplinary)We measured the impact toughness of three alloys (Mg, Mg-0.3 at.% Ca-0.6 at.% Zn, and Mg-0.3 at.% Ca-0.6 at.% Al) by the impact three-point bending test. The plastic deformability and impact toughness were higher in the ternary alloys than in pure Mg. The generalized stacking fault energy and grain boundary cohesive energy were estimated by first-principles calculations for Mg, binary Mg-Ca, ternary Mg-Ca-Zn, and ternary Mg-Ca-Al alloys. The calculation results agreed with the trend in the experimental results. We suggest that addition of Ca along with Zn or Al reduced plastic anisotropy and strengthened the grain boundaries, leading to higher in impact toughness of Mg alloys.
113 of the 113th elementMorita, 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：97.27(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.
Hs and 
HsSato, 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：65.33(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 10.61
0.04 and 10.800.08 MeV. The spontaneous fission branch of Hs was found to be 
.
Sato, Shoichi*; Ichimura, Makoto*; Yamaguchi, Yusuke*; Katano, Makoto*; Imai, Yasutaka*; Murakami, Tatsuya*; Miyake, Yuichiro*; Yokoyama, Takuro*; Moriyama, Shinichi; Kobayashi, Takayuki; et al.
Plasma and Fusion Research (Internet), 5, p.S2067_1 - S2067_4, 2010/12
Ion cyclotron emissions (ICEs) due to deuterium-deuterium fusion-product (FP) ions on JT-60U are studied. ICE due to H-ions is identified from the difference of the toroidal wave number of 2nd ICE(D). The parameter dependence for the appearance of ICE(H) is investigated from the experimental conditions and also is studied by using "Escape Particle Orbit analysis Code (EPOC)".
Kabumoto, Hiroshi; Takeuchi, Suehiro; Ishizaki, Nobuhiro; Yoshida, Takahiro*; Ishiguro, Takayuki*; Yamaguchi, Kazushi*
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1120 - 1122, 2010/03
The JAEA-Tokai tandem accelerator was built for basic science researches with heavy ions. Its superconducting booster was completed in 1994 for increasing the acceleration energy of ions. The booster consists of 40 superconducting acceleration resonators and 10 cryostats. Every resonator is a coaxial quarter wave resonator (QWR) of which frequency is 129.8MHz, and optimum beam velocity is 10% of the light velocity. When it was built, the acceleration field gradients of superconducting resonators were 5.0MV/m at RF power input of 4W on their average. The performance decrease little by little, and it become 4.0MV/m now. Some of the resonators generate X-rays from a low electric field. A field emission will be occurred from small contaminations accumulated on the surfaces of niobium. We examined the high pressure water jet rinsing (HPWR) to re-recondition the superconducting booster. The HPWR is the technology of removing small contaminations on resonator surfaces, and very effective for the improvement of acceleration field gradients. The acceleration field gradients of 20 on-line resonators were improved from 4.4MV to 5.7MV on their average.
Kabumoto, Hiroshi; Takeuchi, Suehiro; Ishizaki, Nobuhiro; Yoshida, Takahiro*; Ishiguro, Takayuki*; Yamaguchi, Kazushi*
Dai-22-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.129 - 132, 2010/01
The JAEA-Tokai tandem accelerator was built for basic science researches with heavy ions. Its superconducting booster was completed in 1994 for increasing the acceleration energy of ions. The booster consists of 40 superconducting acceleration resonators and 10 cryostats. Every resonator is a coaxial quarter wave resonator (QWR) of which frequency is 129.8 MHz, and optimum beam velocity is 10% of the light velocity. When it was built, the acceleration field gradients of superconducting resonators were 5.0 MV/m at RF power input of 4 W on their average. The performance decrease little by little, and it become 4.0 MV/m now. Some of the resonators generate X-rays from a low electric field. A field emission will be occurred from small contaminations accumulated on the surfaces of niobium. We examined the high pressure water jet rinsing (HPWR) to re-recondition the superconducting booster. The HPWR is the technology of removing small contaminations on resonator surfaces, and very effective for the improvement of acceleration field gradients. The acceleration field gradients of 20 on-line resonators were improved from 4.4 MV to 5.7 MV on their average.
Bh and Db produced in the Cm + 
Na reactionMorita, 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：78.34(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.
HsKaji, 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%.
HsKaji, 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：26.3(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 4.1
10
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%.
Hs, 
Sg, and 
RfSato, 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 180
ms of half-life. Another is a long-lived -decay of Rf with 10.4
s 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.
113Morimoto, 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.
Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.
Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01
Times Cited Count：51 Percentile：71.25(Biochemistry & Molecular Biology)Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.
112 by Pb + Zn reactionMorita, 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：150 Percentile：95.98(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 f
r Schwerionenforschung (GSI), Germany. The present result gives the first clear confirmation of the discovery of 112 and its -decay products 
Ds reported previously.
113Morita, 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：97.44(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.
AlOzawa, Akira*; Matsuta, Kensaku*; Nagatomo, Takashi*; Mihara, Mototsugu*; Yamada, Kazunari*; Yamaguchi, Takayuki*; Otsubo, Takashi*; Momota, Sadao*; Izumikawa, Takuji*; Sumikama, Toshiyuki*; et al.
Physical Review C, 74(2), p.021301_1 - 021301_4, 2006/08
Times Cited Count：43 Percentile：89.22(Physics, Nuclear)no abstracts in English
