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1.
Y. Nagame M. Asai H. Haba K. Tsukada I. Nishinaka S. Goto A. Toyoshima K. Akiyama M. Sakama Y. L. Zhao S. Ichikawa H. Nakahara 《Physics of Atomic Nuclei》2003,66(6):1131-1136
The present status of heavy element nuclear chemistry research at JAERI (Japan Atomic Energy Research Institute) is reviewed. Production of the transactinide nuclei 261Rf and 262Db via the reactions of 248Cm(18O,5n) and 248Cm(19F, 5n), respectively, at the JAERI tandem accelerator is reported. Study of the aqueous chemistry of Rf is being carried out with a newly developed rapid ion-exchange separation apparatus. Anion-exchange behavior of Rf in acidic solution is briefly discussed. Recent experimental results on decay studies of neutron-deficient actinide nuclei using the gas-jet coupled JAERI-ISOL are given. We also discuss characteristics of nuclear deformation properties at scission in symmetric and asymmetric fission of actinides. Prospects for studies in the near future are briefly considered. 相似文献
2.
H. Hayashi Y. Akita O. Suematsu M. Shibata M. Asai T. K. Sato S. Ichikawa I. Nishinaka Y. Nagame A. Osa K. Tsukada T. Ishii Y. Kojima A. Taniguchi 《The European Physical Journal A - Hadrons and Nuclei》2007,34(4):363-370
Q
β values of the neutron-rich isotopes of 160-165Eu and 163Gd were measured for the first time using a total absorption bismuth germanate (BGO) detector, and previously obtained data
on 158, 159Pm , 159, 161Sm and 166Tb were re-analyzed. These radioactive sources were prepared by an on-line mass separator (Tokai-ISOL) following the 238U (p,f reaction. The deduced Q
β values are the following: 6085(80)keV for 158Pm , 3805(65)keV for 159Sm , 5460(140)keV for 159Pm , 4705(60)keV for 160Eu , 5065(130)keV for 161Sm , 3705(60)keV for 161Eu , 5575(60)keV for 162Eu , 4690(70)keV for 163Eu , 3170(70)keV for 163Gd , 6430(70)keV for 164Eu , 5800(120)keV for 165Eu , and 4695(70)keV for 166Tb . Moreover, the deduced mass excesses and two-neutron separation energies ( S
2n values) were compared with those of the atomic mass evaluations and theoretical predictions. 相似文献
3.
Y. Nagame I. Nishinaka Y. L. Zhao K. Tsukada S. Ichikawa Z. Qin H. Ikezoe Y. Oura K. Sueki H. Nakahara M. Tanikawa T. Ohtsuki S. Goto H. Kudo Y. Hamajima K. Takamiya K. Nakanishi H. Baba 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(1):97-101
The correlation among the fission threshold energy, the scission configuration and the mass yield distribution has been studied
in proton-induced fission of light actinides. It was found that there exist at least two fission paths from the threshold
region to the scission. The elongated scission configuration is related with the fission process that goes over a higher threshold
energy and results in a symmetric mass division mode, while the compact scission configuration with the process that experiences
a lower threshold and ends up with an asymmetric mass division mode. 相似文献
4.
5.
Y.X. Watanabe A. Yoshida T. Fukuda T. Sekine Y. Watanabe H. Ikezoe Y. Nagame T. Ikuta I. Nishinaka Y. Mizoi J. Nakano M. Hirai H. Sakurai H. Kobinata Y. Pu K. Kimura M. Ishihara 《The European Physical Journal A - Hadrons and Nuclei》2001,10(4):373-379
A systematic study of the sub-barrier fusion reactions with neutron-rich projectiles has been carried out for three isotopes
27,29,31Al bombarding a 197Au target. A target chamber equipped with a target stack and sets of MWPC was employed in order to enhance the efficiency
of the radioactive beam experiment. Coupled-channel calculations including the quadrupole excitations do not well fit the
measured fusion excitation functions, whereas flat barrier distributions to represent the coupling to the neutron transfer
largely account for the observed enhancement of the sub-barrier fusion cross-sections.
Received: 13 March 2001 / Accepted: 27 April 2001 相似文献
6.
Nguyen N. Son Y. Nagame I. Nishinaka 《Journal of Radioanalytical and Nuclear Chemistry》2001,250(2):255-261
Data on fragment mass yields in spontaneous and thermal neutron induced fission of wide range of nuclides from light actinides through heavy actinides were analyzed and completely described as mass distribution parameters, based on the concept of multimodal fission. The evidence that supports the existence of multi-components in the mass distribution of fission fragments, bimodal asymmetric mode in light actinide fission, bimodal symmetric mode in heavy actinide fission, and the existence of the boundaries of fission asymmetry has been obtained. 相似文献
7.
Measurement of evaporation residue cross-sections of the reaction 30Si + 238U at subbarrier energies
K. Nishio S. Hofmann F. P. Heßberger D. Ackermann S. Antalic V. F. Comas Z. Gan S. Heinz J. A. Heredia H. Ikezoe J. Khuyagbaatar B. Kindler I. Kojouharov P. Kuusiniemi B. Lommel R. Mann M. Mazzocco S. Mitsuoka Y. Nagame T. Ohtsuki A. G. Popeko S. Saro H. J. Schött B. Sulignano A. Svirikhin K. Tsukada K. Tsuruta A. V. Yeremin 《The European Physical Journal A - Hadrons and Nuclei》2006,29(3):281-287
The reaction 30Si + 238U → 268Sg* was studied at beam energies close to the Coulomb barrier. At a center-of-mass energy of E
c.m. = 144.0MeV for reactions at half thickness of the target we measured three decay chains of 263Sg produced by evaporation of five neutrons. The cross-section was ( 67+67
-37) pb. At E
c.m. = 133.0MeV we measured three spontaneously fissioning nuclei which we assigned to the isotope 264Sg. The production cross-section was ( 10+10
-6) pb and a half-life of ( 120+126
-44) ms was determined. This half-life is a factor of twenty shorter than theoretical predictions. At E
c.m. = 128.0MeV an upper cross-section limit of 15pb was measured. The cross-section data reveal a strong influence of the orientation
of the deformed target nucleus on the production yield. Compared to excitation functions measured for the lighter system 16O + 238U → 254Fm*, a reduction of the fusion probability was observed at low beam energies indicating increasing competition from quasifission
processes. 相似文献
8.
H. Ikezoe N. Shikazono Y. Tomita Y. Sugiyama K. Ideno W. Yokota Y. Nagame S. M. Lee M. Ogihara S. C. Jeong H. Fujiwara D. J. Hinde 《Zeitschrift für Physik A Hadrons and Nuclei》1988,330(3):289-293
Mass distributions of fission fragments have been measured for the reaction of19F on197Au as a function of scattering angle. The mean fragment mass is dependent on the scattering angle, the asymmetry increasing with increasing projectile energy. 相似文献
9.
A. Yokoyama T. Saito H. Baba K. Hata Y. Nagame S. Ichikawa S. Baba A. Shinohara N. Imanishi 《Zeitschrift für Physik A Hadrons and Nuclei》1989,332(1):61-69
Mechanisms of heavy-ion induced nuclear reactions in mass-asymmetric systems were studied by focusing on the nucleon transfer reaction. Excitation functions and projected mean recoil ranges for the target-like products in37-,16O-,14N-, and12C-induced reactions on197Au were measured by means ofγ-ray spectrometry. The energy range studied was near the Coulomb barrier of the systems with incident energies below 10 MeV/u. Nucleon transfer reactions were discussed by distinguishing the products from quasi-elastic transfer (QET) and those from deep inelastic transfer (DIT). The tendency towards equilibration of theN/Z value and the energy damping, which are the characteristic features of DIT, were found in the production of Au isotopes. Observations are consistent with the generally accepted concept that QET takes place along a trajectory near the Coulomb trajectory. QET was made to be connected with the interaction radius and most of the cross section ratios were reproduced well by an extended tunneling model. 相似文献
10.
H. Kudo K. Okuno H. Sugai Y. Nagame 《Journal of Radioanalytical and Nuclear Chemistry》1985,93(1):55-64
Chemical states of tritium existing in neutron-irradiated solid lithium compounds were analyzed using a radiometric method. Nearly 100% of tritium was found in the T+ state in LiOH, Li2O2 and Li3N, while the T– state predominated in LiH, Li7Pb2 and Li2C2. Tritium incorporated in Li2O, Li2S, LiF, LiCl, LiBr and LiI was distributed over the T+, T– and T0 states. In Li2O crystals, the distribution of tritium in the T+ state increased from 58% to 81% with increasing neutron fluence from 2.5×1016 cm–2 to 6.3×1017 cm–2. 相似文献