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Huang, M.*; Haba, Hiromitsu*; Murakami, Masashi*; Asai, Masato; Kaji, Daiya*; Kanaya, Jumpei*; Kasamatsu, Yoshitaka*; Kikunaga, Hidetoshi*; Kikutani, Yuki*; Komori, Yukiko*; et al.
Journal of Radioanalytical and Nuclear Chemistry, 304(2), p.845 - 849, 2015/05
Times Cited Count:3 Percentile:23.54(Chemistry, Analytical)A technique to utilize radioisotopes of Nb and Ta was developed for chemical studies of element 105, Db, by coupling a gas-jet transport system to the RIKEN gas-filled recoil ion separator (GARIS). The short-lived Nb and
Ta were produced with nuclear reactions using a
F beam whose energy was the same as that to produce
Db. Then, they were separated with GARIS and extracted to a chemistry laboratory with the gas-jet transport system. By changing only magnetic field of GARIS and inserting an energy degrader and a shutter for recoil ions, we could deliver the
Nb and
Ta to a chemistry device for
Db without changing other experimental conditions.
Haba, Hiromitsu*; Huang, M.*; Kaji, Daiya*; Kanaya, Jumpei*; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Murakami, Masashi*; Ozeki, Kazutaka*; Sakai, Ryutaro*; et al.
Physical Review C, 89(2), p.024618_1 - 024618_11, 2014/02
Times Cited Count:27 Percentile:81.97(Physics, Nuclear)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:178 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.
Haba, Hiromitsu*; Kaji, Daiya*; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Ozeki, Kazutaka*; Sakai, Ryutaro*; Sumita, Takayuki*; Yoneda, Akira*; Kasamatsu, Yoshitaka*; et al.
Physical Review C, 85(2), p.024611_1 - 024611_11, 2012/02
Times Cited Count:56 Percentile:91.28(Physics, Nuclear)Two isomeric states in Sg, i.e,
Sg
and
Sg
were produced in the
Cm(
Ne,5
) reaction. Decay properties of
Sg
were investigated with a rotating-wheel apparatus for
and spontaneous fission (SF) spectrometry under low background condition attained by a gas-jet transport system coupled to the RIKEN gas-filled recoil ion separator. Based on genetically correlated
-
(-
) and
-SF decay chains, 18 and 24 events were assigned to
Sg
and
Sg
, respectively. The half-life and
-particle energy of
Sg
were measured to be
s and
MeV, respectively, and those of
Sg
were
s and
MeV.
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:16 Percentile:65.66(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 10.80
0.08 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:77.51(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:25.59(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 6.2
10
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%.
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.
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 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.
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.
Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi; Yoneda, Akira*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Sumita, Takayuki*; Morita, Kosuke*
no journal, ,
We designed a new gas-filled recoil ion separator GARIS-II for actinide-based asymmetric fusion (hot fusion) study at RIKEN. GARIS-II was designed on the basis of extensive experiences with construction, development, and operation of GARIS. GARIS-II consists of five magnets arranged in a Qv-D-Qh-Qv-D configuration, where D and Q denote dipole and quadrupole magnets, respectively. Ion optical characteristics were analyzed using the computer code TRANSPORT. The solid angle of GARIS-II is 20.2 msr. The total path length of the separator is 5.12 m. GARIS-II will be able to use various filled gas, such as He and He/H2 mixture. The separator will be able to transport the recoil ion with magnetic rigidity of 2.44 Tm.
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.
Kaji, Daiya*; Haba, Hiromitsu*; Kasamatsu, Yoshitaka*; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Ozeki, Kazutaka*; Sumita, Takayuki*; Yoneda, Akira*; Sato, Nozomi; et al.
no journal, ,
RIKEN group has been developing a new gas-filled recoil ion separator GARIS-II for research of superheavy element produced by actinide-based asymmetric fusion (hot fusion) reactions. The GARIS-II consists of five magnets with a Q-D-Q-Q-D configuration. Where, D and Q are dipole and quadrupole magnets, respectively. The test of GARIS-II was performed with the Am standard
-source and 0
scattered ions from the
Pb target. A solid angle of GARIS-II was measured to be about 18.4 msr, which was almost as same as a calculated value with the TRANSPORT cord. The image size at focal plane versus He-gas pressure in GARIS-II chamber was also measured with
Pb ions.
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.
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
Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; Ozeki, Kazutaka*; et al.
no journal, ,
no abstracts in English
Sato, Nozomi; Kaji, Daiya*; Morimoto, Koji*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; Ozeki, Kazutaka*; et al.
no journal, ,
In the superheavy nuclei region, the deformed proton shell at and neutron shells at
and 162 have been found.
Hs with
and
is expected to be the doubly deformed magic nuclei, however, decay properties of
Hs and its neighboring nuclei is not well known. In order to approach
Hs, we synthesized
Hs by
Pb(
Fe,xn) [
],
Pb(
Fe,n),
Pb(
Fe,n),
Pb(
Fe,n) reactions. The experiment was performed with the gas-filled recoil ion separator GARIS at the linear accelerator facility in RIKEN. In this work, 9
-decay events of
Hs were observed with half-life
ms and
-decay energy
MeV. For
Hs, we have also observed new
-particle energy, 10.65 MeV.
values of
Hs isotopes increase with decreasing neutron number.
Kaji, Daiya*; Haba, Hiromitsu*; Kasamatsu, Yoshitaka*; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Ozeki, Kazutaka*; Sumita, Takayuki*; Yoneda, Akira*; Koura, Hiroyuki; et al.
no journal, ,
no abstracts in English
Haba, Hiromitsu*; Oe, Kazuhiro*; Ozeki, Kazutaka*; Kasamatsu, Yoshitaka*; Kaji, Daiya*; Kikunaga, Hidetoshi*; Kudo, Hisaaki*; Kudo, Yuki*; Komori, Yukiko*; Sato, Nozomi; et al.
no journal, ,
RIKEN group has investigated the performance of the system using an isotope of element 106, Sg, produced in the
Cm(
Ne,5
) reaction. Alpha-particles of
Sg separated with a GAs-filled Recoil Ion Separator (GARIS) and extracted to a chemistry laboratory were successfully identified with a rotating wheel system for
-spectrometry under low background conditions. As a result, two isomeric states in
Sg,
Sg (
-particle energy
MeV, half-life
s) and
Sg (
MeV,
s), were identified. The cross sections for the
Cm(
Ne,5
) reactions at 118 MeV were roughly evaluated to be 200 pb for
Sg and 170 pb for
Sg.