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Journal Articles

Adsorption behavior of $$^{95}$$Nb and $$^{179}$$Ta as homologues of element 105, Db, on cation exchanger in HF/HNO$$_{3}$$ solution

Kasamatsu, Yoshitaka*; Toyoshima, Atsushi; Tome, Hayato*; Tsukada, Kazuaki; Asai, Masato; Haba, Hiromitsu*; Nagame, Yuichiro

Journal of Nuclear and Radiochemical Sciences (Internet), 13(1), p.9 - 12, 2013/06

Adsorption behavior of the group-5 elements, $$^{95}$$Nb and $$^{179}$$Ta, on cation-exchange resin was studied in mixed solution of HF and HNO$$_{3}$$ as a model experiment of their heavier homologue, element 105 (dubnium, Db). Chemical reactions of these elements in the cation exchange rapidly reached the equilibrium. It was found that distribution coefficients of Nb and Ta decrease with increasing the fluoride ion concentration in the studied range of 10$$^{-7}$$ - 10$$^{-5}$$ M. Clear difference between Nb and Ta was observed in the variations of the distribution coefficients against the fluoride ion concentration. This would originate from their different chemical species of fluoride complexes. We propose the cation-exchange experiment of Db based on the present experimental results to understand its fluoride complex formation.

Journal Articles

Extraction of chromatographic behavior of Rf, Zr, and Hf in HCl solution with styrenedivinylbenzene copolymer resin modified by TOPO (trioctylphosphine oxide)

Toyoshima, Atsushi; Kasamatsu, Yoshitaka*; Tsukada, Kazuaki; Asai, Masato; Ishii, Yasuo; Tome, Hayato*; Nishinaka, Ichiro; Sato, Tetsuya; Nagame, Yuichiro; Sch$"a$del, M.; et al.

Journal of Nuclear and Radiochemical Sciences, 11(1), p.7 - 11, 2010/06

The extraction behavior of rutherfordium (Rf) into trioctylphosphine oxide (TOPO) from 2.0 - 7.0 M HCl solution was studied together with that of the homologues Zr and Hf. The extracted yields of Rf, Zr, and Hf increased with an increase of HCl concentration, and the sequence of their extraction was Zr $$>$$ Hf $$geq$$ Rf. It is suggested that the stability of the RfCl$$_{4}$$$$cdot$$2(TOPO) complex is lower than that of the corresponding species of the homologues.

Journal Articles

Anionic fluoro complex of element 105, Db

Kasamatsu, Yoshitaka*; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Li, Z.; Ishii, Yasuo; Tome, Hayato*; Sato, Tetsuya; Kikuchi, Takahiro; Nishinaka, Ichiro; et al.

Chemistry Letters, 38(11), p.1084 - 1085, 2009/10

 Times Cited Count:13 Percentile:48.46(Chemistry, Multidisciplinary)

We report on the characteristic anion-exchange behavior of the superheavy element dubnium (Db) with atomic number Z = 105 in HF/HNO$$_{3}$$ solution at the fluoride ion concentration [F$$^{-}$$] = 0.003 M. The result clearly demonstrates that the fluoro complex formation of Db is significantly different from that of the group-5 homologue Ta in the 6th period of the periodic table while the behavior of Db is similar to that of the lighter homologue Nb in the 5th period.

Journal Articles

Oxidation of element 102, nobelium, with flow electrolytic column chromatography on an atom-at-a-time scale

Toyoshima, Atsushi; Kasamatsu, Yoshitaka*; Tsukada, Kazuaki; Asai, Masato; Kitatsuji, Yoshihiro; Ishii, Yasuo; Tome, Hayato; Nishinaka, Ichiro; Haba, Hiromitsu*; Oe, Kazuhiro*; et al.

Journal of the American Chemical Society, 131(26), p.9180 - 9181, 2009/07

 Times Cited Count:8 Percentile:59.46(Chemistry, Multidisciplinary)

We report here on the successful oxidation of element 102, nobelium (No), on an atom-at-a-time scale in 0.1 M $$alpha$$-hydroxyisobutyric acid ($$alpha$$-HIB) solution using newly developed flow electrolytic column chromatography. It is found that the most stable No$$^{2+}$$ is oxidized to No$$^{3+}$$ within 3 min and that the oxidized No complex with $$alpha$$-HIB holds the trivalent state in the column above the applied potential of 1.0 V.

Journal Articles

Adsorption of Nb, Ta and Pa on anion-exchanger in HF and HF/HNO$$_{3}$$ solutions; Model experiments for the chemical study of Db

Kasamatsu, Yoshitaka; Toyoshima, Atsushi; Haba, Hiromitsu*; Tome, Hayato*; Tsukada, Kazuaki; Akiyama, Kazuhiko*; Yoshimura, Takashi*; Nagame, Yuichiro

Journal of Radioanalytical and Nuclear Chemistry, 279(2), p.371 - 376, 2009/02

 Times Cited Count:11 Percentile:31.4(Chemistry, Analytical)

Anion-exchange behavior of the group-5 elements Nb and Ta, and their pseudo homologue Pa in HF and HF/HNO$$_{3}$$ solutions was investigated by a batch method to find suitable conditions for the anion-exchange experiment of element 105 (Dubnium, Db). We determined distribution coefficients of those elements on the anion-exchange resin as a function of the F$$^{-}$$ and NO$$_{3}$$$$^{-}$$ concentrations. Clearly different anion-exchange behavior was observed among these elements. Based on the results, we discuss the fluoro-complex formation of each element and suggest experimental conditions for the study of fluoride complexation of Db.

Journal Articles

Observation of high-$$j$$ quasiparticle states in $$^{249}$$Cm by in-beam $$gamma$$-ray spectroscopy using heavy-ion transfer reactions

Ishii, Tetsuro; Makii, Hiroyuki*; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shigematsu, Soichiro*; Kaneko, Junichi*; Shizuma, Toshiyuki; et al.

Physical Review C, 78(5), p.054309_1 - 054309_11, 2008/11

 Times Cited Count:13 Percentile:31.26(Physics, Nuclear)

Journal Articles

In-beam $$gamma$$-ray spectroscopy of neutron-rich nuclei in the uranium region through the heavy-ion transfer reaction

Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Koura, Hiroyuki; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; et al.

Nuclear Physics A, 805(1-4), p.257 - 259, 2008/06

no abstracts in English

Journal Articles

Fluoride complexation of element 104, rutherfordium (Rf), investigated by cation-exchange chromatography

Ishii, Yasuo; Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Tome, Hayato; Nishinaka, Ichiro; Nagame, Yuichiro; Miyashita, Sunao*; Mori, Tomotaka*; Suganuma, Hideo*; et al.

Chemistry Letters, 37(3), p.288 - 289, 2008/03

 Times Cited Count:17 Percentile:43.4(Chemistry, Multidisciplinary)

We have investigated cation-exchange behavior of Rf together with the lighter homologues of the group-4 elements Zr and Hf, and the tetravalent pseudo-homologue Th, in HF/HNO$$_{3}$$ solution using Automated Ion exchange separation apparatus coupled with the Detection system for Alpha spectroscopy (AIDA). The ${it K}$ $$_{d}$$ values of Zr, Hf, Th and Rf in HF/0.1 M HNO$$_{3}$$ were decreased with increasing the concentration of the fluoride ion [F$$^{-}$$], indicating the formation of the fluoride complexes. The sequence of the fluoride complexation strength is Zr $$sim$$ Hf $$>$$ Rf $$>$$ Th.

Journal Articles

Z dependence of the $$N = 152$$ deformed shell gap; In-beam $$gamma$$-ray spectroscopy of neutron-rich $$^{245, 246}$$Pu

Makii, Hiroyuki; Ishii, Tetsuro; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; Tome, Hayato*; Ichikawa, Shinichi; et al.

Physical Review C, 76(6), p.061301_1 - 061301_5, 2007/12

 Times Cited Count:25 Percentile:14.56(Physics, Nuclear)

We have measured deexcitation $$gamma$$ rays for the first time in the neutron-rich nuclei of $$^{246}$$Pu$$_{152}$$ and $$^{245}$$Pu$$_{151}$$ produced by the ($$^{18}$$O, $$^{16}$$O) and the ($$^{18}$$O, $$^{17}$$O) reactions, respectively. The ground-state band of $$^{246}$$Pu was established up to 12$$^{+}$$ states. The systematics of the moments of inertia of $$_{94}$$Pu isotopes suggests that the $$N = 152$$ deformed subshell closure disappears in these isotopes. The measurements of deexcitation $$gamma$$ rays in $$^{245}$$Pu shows a small energy spacing between neutron orbitals at $$N = 152$$, which explans the disappearance of the subshell closure.

Journal Articles

Anion-exchange behavior of Nb, Ta, and Pa as homologues of Db in HF/HNO$$_{3}$$ solutions

Kasamatsu, Yoshitaka; Toyoshima, Atsushi; Tome, Hayato; Tsukada, Kazuaki; Haba, Hiromitsu*; Nagame, Yuichiro

Journal of Nuclear and Radiochemical Sciences, 8(2), p.69 - 72, 2007/10

We investigated anion-exchange behavior of Nb, Ta and Pa in HF/HNO$$_{3}$$ media to find suitable experimental conditions for the study of the Db fluoride complex formation. We measured Kd values of Nb, Ta and Pa on strong basic anion exchangers in the wide range of the fluoride ion concentration, 1$$times$$10$$^{-6}$$$$sim$$2$$times$$10$$^{-2}$$M, in order to in detail investigate anionic fluoride complex formation of those elements. We have used tracer concentrations of isotopes of $$^{95}$$Nb, $$^{179}$$Ta and $$^{233}$$Pa in the experiments. Variation of the Kd values as a function of [NO$$_{3}$$$$^{-}$$] was also studied. As a result, we observed an apparent difference in the adsorption behavior of the homologues. Based on these results together with the measurement of the equilibrium time, we propose rapid online experimental condition for the study of Db fluoride.

Journal Articles

In-beam $$gamma$$-ray study of the neutron-rich nuclei of $$^{240}$$U, $$^{246}$$Pu, and $$^{250}$$Cm produced by the ($$^{18}$$O, $$^{16}$$O) reaction

Ishii, Tetsuro; Shigematsu, Soichiro*; Makii, Hiroyuki; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; Kaneko, Junichi*; et al.

Physics of Atomic Nuclei, 70(8), p.1457 - 1461, 2007/08

 Times Cited Count:8 Percentile:41.71(Physics, Nuclear)

We have measured deexcitation $$gamma$$ rays in the neutron-rich nuclei of $$^{240}$$U, $$^{246}$$Pu and $$^{250}$$Cm. These nuclei were produced by the ($$^{18}$$O, $$^{16}$$O) two-neutron transfer reactions with a 200, 162 and 162 MeV $$^{18}$$O beams and a $$^{238}$$U, $$^{244}$$Pu and $$^{248}$$Cm targets, respectively, using the tandem accelerator at Tokai, Japan. The $$gamma$$ rays in residual nuclei were measured by taking coincidence with scattering particles using Si $$Delta E$$-$$E$$ detectors. We have identified $$gamma$$ rays in $$^{240}$$U, $$^{246}$$Pu and $$^{250}$$Cm by selecting the kinetic energies of $$^{16}$$O particles which correspond to the excitation energies in these nuclei below their neutron separation energies. The ground-state bands of $$^{240}$$U, $$^{246}$$Pu and $$^{250}$$Cm were established up to 12$$^{+}$$ states and the $$K^{pi}=0^{-}$$ octupole band of $$^{240}$$U was established up to 9$$^{-}$$ state. Because the deformations of these nuclei are well developed, the moments of inertia reflect the pairing gap, which is expected to be smaller, resulting in a larger moment of inertia, at the deformed shell closure. We have found that the moment of inertia of the ground-state band of $$^{248}$$Cm$$_{152}$$ is considerably larger than that of $$^{250}$$Cm$$_{154}$$. This fact supports the existence of the deformed subshell closure at $$N=152$$ in Cm isotopes. On the other hand, the moment of inertia of $$^{246}$$Pu$$_{152}$$ was found to be smaller than that of $$^{244}$$Pu$$_{150}$$, which suggests that the deformed subshell closure at $$N=152$$ weakens or disappears in Pu isotopes. These results are consistent with the prediction by a cranking model calculation.

Journal Articles

Ground-state bands of neutron-rich $$^{236}$$Th and $$^{242}$$U nuclei and implication of spherical shell closure at $$N=164$$

Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Koura, Hiroyuki; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; et al.

Physical Review C, 76(1), p.011303_1 - 011303_5, 2007/07

 Times Cited Count:13 Percentile:29.38(Physics, Nuclear)

The ground-state bands of the neutron-rich $$^{236}$$Th and $$^{242}$$U nuclei were established up to spin 10 and 8, respectively, by in-beam $$gamma$$-ray spectroscopy using the ($$^{18}$$O, $$^{20}$$Ne) two-proton pickup reaction with a $$^{238}$$U and a $$^{244}$$Pu target. Deexcitation $$gamma$$ rays in $$^{236}$$Th and $$^{242}$$U were identified by selecting the kinetic energies of $$^{20}$$Ne using Si $$Delta E$$-$$E$$ detectors. The excitation energies of the first 2$$^{+}$$ states in U and Pu isotopes have local minima at $$N simeq 146$$, suggesting the possibility that nuclei with $$Z simeq 92$$ have a spherical shell closure of $$N=164$$. Calculation using the Koura-Yamada single-particle potential gives an energy gap of 1.8 MeV at $$N=164$$ for $$^{256}$$U.

Journal Articles

Extraction behavior of rutherfordium into tributylphosphate from hydrochloric acid

Haba, Hiromitsu*; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Ishii, Yasuo; Tome, Hayato; Sato, Tetsuya; Nishinaka, Ichiro; Ichikawa, Takatoshi; Ichikawa, Shinichi; et al.

Radiochimica Acta, 95(1), p.1 - 6, 2007/01

 Times Cited Count:14 Percentile:24.72(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Ground-state band of the neutron-rich transuranium nucleus $$^{250}$$Cm$$_{154}$$

Ishii, Tetsuro; Shigematsu, Soichiro; Makii, Hiroyuki; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; Kaneko, Junichi*; et al.

Journal of the Physical Society of Japan, 75(4), p.043201_1 - 043201_4, 2006/04

 Times Cited Count:19 Percentile:27.77(Physics, Multidisciplinary)

The ground-state band of the neutron-rich transuranium nucleus $$^{250}$$Cm was established up to spin 12 by in-beam $$gamma$$-ray spectroscopy using the two-neutron-transfer reaction with a $$^{248}$$Cm target and a 162 MeV $$^{18}$$O beam. Deexcitation $$gamma$$ rays in $$^{250}$$Cm were identified by selecting the kinetic energies of $$^{16}$$O particles with Si $$Delta E$$-$$E$$ detectors. The moment of inertia of $$^{250}$$Cm$$_{154}$$ is considerably smaller than that of $$^{248}$$Cm$$_{152}$$, which supports the existence of the deformed subshell closure at $$N=152$$ in Cm isotopes.

Oral presentation

In-beam $$gamma$$-ray measurement of the neutron-rich nucleus $$^{250}_{96}$$Cm$$_{154}$$

Ishii, Tetsuro; Shigematsu, Soichiro; Makii, Hiroyuki; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; Kaneko, Junichi*; et al.

no journal, , 

no abstracts in English

Oral presentation

Formation of anionic chloride complex of Rutherfordium (Rf)

Tsukada, Kazuaki; Toyoshima, Atsushi; Haba, Hiromitsu*; Asai, Masato; Akiyama, Kazuhiko*; Ishii, Yasuo; Tome, Hayato*; Nishinaka, Ichiro; Sato, Tetsuya; Ichikawa, Takatoshi; et al.

no journal, , 

no abstracts in English

Oral presentation

TBP reversed-phase extraction chromatography of Rutherfordium in the HCl solution

Toyoshima, Atsushi; Haba, Hiromitsu*; Tsukada, Kazuaki; Asai, Masato; Akiyama, Kazuhiko*; Ishii, Yasuo; Tome, Hayato*; Nishinaka, Ichiro; Sato, Tetsuya; Ichikawa, Takatoshi; et al.

no journal, , 

no abstracts in English

Oral presentation

In beam $$gamma$$-ray measurement of the neutron-rich nucleus $$^{246}$$Pu

Makii, Hiroyuki; Ishii, Tetsuro; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; Tome, Hayato; Ichikawa, Shinichi; et al.

no journal, , 

no abstracts in English

Oral presentation

Chloride complex formation of Rf in HCl and CH$$_{3}$$OH mixed solution

Tsukada, Kazuaki; Toyoshima, Atsushi; Haba, Hiromitsu*; Asai, Masato; Akiyama, Kazuhiko*; Ishii, Yasuo; Tome, Hayato; Nishinaka, Ichiro; Sato, Tetsuya; Ichikawa, Shinichi; et al.

no journal, , 

no abstracts in English

Oral presentation

Adsorption of Nb, Ta and Pa on anion exchangers in diluted HF media

Kasamatsu, Yoshitaka; Toyoshima, Atsushi; Tome, Hayato; Tsukada, Kazuaki; Haba, Hiromitsu*; Nagame, Yuichiro

no journal, , 

no abstracts in English

44 (Records 1-20 displayed on this page)