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U oxide and fluorideShigekawa, Yudai*; Kasamatsu, Yoshitaka*; Yasuda, Yuki*; Kaneko, Masashi; Watanabe, Masayuki; Shinohara, Atsushi*
Physical Review C, 98(1), p.014306_1 - 014306_5, 2018/07
Times Cited Count：4 Percentile：36.29(Physics, Nuclear)The nuclear half-life of U has been reported to vary depending on the chemical environment. In this study, both the half-life and the internal-conversion (IC) electron energy spectrum were measured for U with identical chemical environments for the first time. U oxide and fluoride samples were subjected to these measurements, and clear differences in the half-life and the energy spectrum between these samples were observed. The peaks in the energy spectra were identified with the relativistic density functional theory calculation, and the molecular orbital states of the U oxide and fluoride estimated from the energy spectra and the calculation qualitatively explained the difference in the half-lives between the samples.
Ru
)
Sb
investigated by inelastic X-ray scatteringTsutsui, Satoshi; Kaneko, Koji; Miyazaki, Ryoichi*; Higashinaka, Ryuji*; Aoki, Yuji*; Kobayashi, Riki*; Wakimoto, Shuichi; Baron, A. Q. R.*; Sugawara, Hitoshi*; Sato, Hideyuki*
JPS Conference Proceedings (Internet), 3, p.011060_1 - 011060_5, 2014/06
Chiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Yamada, Keisuke; Kaneko, Toshiaki*
Nuclear Instruments and Methods in Physics Research B, 315, p.81 - 84, 2013/11
Times Cited Count：1 Percentile：11.54(Instruments & Instrumentation)The average charge of the constituent ions resulting from foil-induced dissociation of cluster ion is smaller than that of the single ion passing through the foil at same speed. This charge reduction effect is one of the most important phenomena for understanding the interaction of cluster ions with electrons in a solid, and the theories suggested that it strongly depends on the internuclear distance of the constituent ions. However, the relationship between the internuclear distance and the charge state has still not been shown quantitatively. We developed a method to evaluate the relationship by analyzing the divergence angle of the constituent ions after foil penetration using Coulomb explosion imaging technique. As a result for 6-MeV C
, it was shown quantitatively that the charge reduction effect decreases with increasing the internuclear distance of the constituent ion in the solid.
ion moving in a solidChiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Yamada, Keisuke; Kaneko, Toshiaki*
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 161, 2013/01
An average charge of the constituent ions resulting from the foil-induced dissociation of cluster ions is smaller than that of monatomic ions at the same speed. It is considered that such a charge reduction effect in cluster ion bombardments depend strongly on the internuclear distance between constituent ions moving in a solid. However, there are few reports in which average charges of the constituent ions had been quantitatively evaluated in terms of their internuclear distance increasing by the screened Coulomb repulsion. Therefore, we developed a method which evaluate quantitatively the average charge for internuclear distance of constituent ions in solid through the measurements of the divergence angle of the constituent ions after foil penetration. The achieved results are approximately equal to the theoretical value derived from model considering the cluster effect in average charge.
Kaneko, Toshiaki*; Ihara, Kosuke*; Kono, Maasa*; Saito, Yuichi; Chiba, Atsuya; Narumi, Kazumasa
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 164, 2013/01
Ga
O (x =0, 0.018)Nakajima, Taro*; Mitsuda, Setsuo*; Takahashi, Keiichiro*; Yoshitomi, Keisuke*; Masuda, Kazuya*; Kaneko, Chikafumi*; Homma, Yuki*; Kobayashi, Satoru*; Kitazawa, Hideaki*; Kosaka, Masashi*; et al.
Journal of the Physical Society of Japan, 81(9), p.094710_1 - 094710_8, 2012/09
GaO (
= 0, 0.018)Nakajima, Taro*; Mitsuda, Setsuo*; Takahashi, Keiichiro*; Yoshitomi, Keisuke*; Masuda, Kazuya*; Kaneko, Chikafumi*; Homma, Yuki*; Kobayashi, Satoru*; Kitazawa, Hideaki*; Kosaka, Masashi*; et al.
Journal of the Physical Society of Japan, 81(9), p.094710_1 - 094710_8, 2012/09
Times Cited Count：13 Percentile：63.29(Physics, Multidisciplinary)Chiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Yamada, Keisuke; Kaneko, Toshiaki*
Dai-25-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.98 - 101, 2012/07
Availability of the swift cluster ion is expected as new irradiation source, because the cluster ion bombardment to the solid brings irradiation effects different from the monatomic ion bombardment at the same speed. This unique effect, cluster effect, is caused via the physical processes that a number of high energy ions within a narrow spatiotemporal region make the high density excited states and that the constituent ion influences with respect to one another. For understanding of the expression mechanism of cluster effect, detailed investigation of these two physical processes are needed. In this study, with a focus on the interaction between constituent ions, we developed an analyzing method that shows quantitatively the relationship between the internuclear distance of constituent ions and their charge states, using the Coulomb explosion imaging technique, to investigate the contribution of the screened Coulomb potential to the cluster effect.
Kaneko, Toshiaki*; Saito, Yuichi; Chiba, Atsuya; Narumi, Kazumasa
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 153, 2012/01
ionsChiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Yamada, Keisuke; Kaneko, Toshiaki*
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 151, 2012/01
In order to understand the mechanism of charge reduction in cluster ions observed in the foil-transmission experiments, we investigate contributions to charge states of the cluster constituent ions from ion-induced potential. For the C ions passing through a this foil, we found out that the charge states of tracing ions are larger than that of leading ions.
ion passing through a thin foilChiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Yamada, Keisuke; Kaneko, Toshiaki*
Dai-24-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.121 - 124, 2011/07
The average charge states of swift cluster ions passed through a thin foil are smaller than that of the single ions at the same speed. It is considered that such a phenomenon is derived from the mutual screened Coulomb interactions among the cluster constituent ions and the collective excitations of the target electrons induced by the constituent ions. In order to evaluate the contribution to the charge states from the fields of the collective excitations formed at the backward of the moving ion, using the C ions, the charge states measurements were performed taking into account the relative position (leading and trailing) of the constituent ions. The experimental results showed that the charge states of the trailing ions are larger than that of the leading ions, and that this tendency becomes strong with increasing the product of charges.
constituents passing through a thin carbon foilChiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Takahashi, Yasuyuki; Yamada, Keisuke; Kaneko, Toshiaki*
Nuclear Instruments and Methods in Physics Research B, 269(9), p.824 - 828, 2011/05
Times Cited Count：3 Percentile：26.67(Instruments & Instrumentation)It is necessary to clarify the relationship between the internuclear distance of the cluster constituent ions and these charge states for the elucidation of mechanism of the vicinage effects which are expressed due to the interaction with matter. Therefore the coincidence measurement between divergence angles and final charge states of the constituent ions resulting from dissociation of 6-MeV C ions in a thin carbon foil were performed. The strong dependence of the final charge state of constituent ions on the initial internuclear distance of projectile ion was quantitatively indicated by the fitting analysis of the angular distributions for various final charge-state combinations using the Monte Carlo particle trajectory simulation.
ionsChiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Takahashi, Yasuyuki; Yamada, Keisuke; Kaneko, Toshiaki*
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 163, 2011/01
The evaluation of the charge state and charge exchange process of the cluster constituent ions inside solid is extremely important for the clarification of the vicinage effect, because the essential interaction forces such as stopping power, wake force and Coulomb repulsion is strongly correlated to the charge state of individual constituent ions. Therefore, the measurement of the divergence angular distributions classified into the charge-state combination of constituent ions resulting from foil-induced dissociation of 6-MeV C ions was carried out in order to investigate the relationship between the internuclear distance and the charge state of individual constituent ions. We suggests that the final charge-state combination of constituents emerging from the foil depends on the initial internuclear-distance which is fluctuated due to a vibration excitation of C ion.
Chiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Adachi, Masahiro; Yamada, Keisuke; Takahashi, Yasuyuki; Kaneko, Toshiaki*
JAEA-Conf 2008-012, p.84 - 86, 2009/03
no abstracts in English
quasiparticle states in 
Cm by in-beam 
-ray spectroscopy using heavy-ion transfer reactionsIshii, 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：14 Percentile：64.91(Physics, Nuclear)
cluster ion structure utilizing coulomb explosion imagingAdachi, Masahiro; Saito, Yuichi; Chiba, Atsuya; Narumi, Kazumasa; Yamada, Keisuke; Kaneko, Toshiaki*
Radiation Physics and Chemistry, 77(10-12), p.1328 - 1332, 2008/10
Times Cited Count：1 Percentile：10.05(Chemistry, Physical)no abstracts in English
-ray spectroscopy of neutron-rich nuclei in the uranium region through the heavy-ion transfer reactionIshii, 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
cluster ionChiba, Atsuya; Saito, Yuichi; Narumi, Kazumasa; Adachi, Masahiro; Kaneko, Toshiaki*
Physical Review A, 76(6), p.063201_1 - 063201_6, 2007/12
Times Cited Count：13 Percentile：54.37(Optics)The charge states of fragment ions were measured for 1-MeV/atom C cluster ions penetrating a carbon foil of 2.4-
g/cm
thickness. Those ions were detected with a luminance plate detector monitored by a CCD camera. The detected ion signals were traced by coulomb explosion imaging technique, which enabled us to classify charge states of each fragment ion and spatial structure of a cluster ion on emerging from the foil. Using this technique, for the first time, we found that (1) the measured average charges of the fragment ions in a triangular structure are smaller than those in a linear-chain structure, and (2) the edge-position ions in a linear structure have the average charges greater than the middle-position ion. These experimental results are well supported by a recent theory on the cluster average charge.
deformed shell gap; In-beam -ray spectroscopy of neutron-rich 
PuMakii, 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：28 Percentile：83.47(Physics, Nuclear)We have measured deexcitation rays for the first time in the neutron-rich nuclei of 
Pu
and 
Pu
produced by the (
O, 
O) and the (O, 
O) reactions, respectively. The ground-state band of Pu was established up to 12 states. The systematics of the moments of inertia of 
Pu isotopes suggests that the deformed subshell closure disappears in these isotopes. The measurements of deexcitation rays in Pu shows a small energy spacing between neutron orbitals at , which explans the disappearance of the subshell closure.
-ray study of the neutron-rich nuclei of 
U, Pu, and 
Cm produced by the (O, O) reactionIshii, 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：9 Percentile：56.38(Physics, Nuclear)We have measured deexcitation rays in the neutron-rich nuclei of U, Pu and Cm. These nuclei were produced by the (O, O) two-neutron transfer reactions with a 200, 162 and 162 MeV O beams and a 
U, 
Pu and 
Cm targets, respectively, using the tandem accelerator at Tokai, Japan. The rays in residual nuclei were measured by taking coincidence with scattering particles using Si 
-
detectors. We have identified rays in U, Pu and Cm by selecting the kinetic energies of O particles which correspond to the excitation energies in these nuclei below their neutron separation energies. The ground-state bands of U, Pu and Cm were established up to 12 states and the 
octupole band of 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 Cm is considerably larger than that of Cm
. This fact supports the existence of the deformed subshell closure at 
in Cm isotopes. On the other hand, the moment of inertia of Pu was found to be smaller than that of Pu
, which suggests that the deformed subshell closure at weakens or disappears in Pu isotopes. These results are consistent with the prediction by a cranking model calculation.
