KINDAI UNIVERSITY


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ARITOMO Yoshihiro

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FacultyDepartment of Electric and Electronic Engineering / Graduate School of Science and Engineering Research
PositionAssociate Professor
Degree
Commentator Guidehttps://www.kindai.ac.jp/meikan/1376-aritomo-yoshihiro.html
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Last Updated :2020/04/06

Research Activities

Research Areas

  • Natural sciences, Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics, Reaction Theory

Published Papers

  • Origin of the dramatic change of fission mode in fermium isotopes investigated using Langevin equations, Y. Miyamoto, Y. Aritomo, S. Tanaka, K. Hirose, K. Nishio, Physical Review C, Physical Review C, 99, 051601(R), May 2019 , Refereed
  • Dynamical Approach for Synthesis of Superheavy Elements: Fusion Mechanism and Nuclear Structure, Y. Aritomo, N. Liyana, B. Yanagi, H. Hachikubo, Eurasian Journal of Physics and Functional Materials, Eurasian Journal of Physics and Functional Materials, 3(3), 197 - 203, 2019 , Refereed
  • Dynamical Study on the Synthesis of Superheavy Elements, Yoshihiro Aritomo, Frontiers in Nuclear and Particle Physics, Frontiers in Nuclear and Particle Physics, 2, 255 - 282, 2019 , Refereed
  • Study of fission using multi-nucleon transfer reactions, Katsuhisa Nishio, Kentaro Hirose, Mark Vermeulen, Hiroyuki Makii, Riccardo Orlandi, Kazuaki Tsukada, Masato Asai, Atsushi Toyoshima, Tetsuya K. Sato, Yuichiro Nagame, Satoshi Chiba, Yoshihiro Aritomo, Shouya Tanaka, Tsutomu Ohtsuki, Igor Tsekhanovich, Costel M. Petrache, Andrei Andreyev, Andrei Andreyev, EPJ Web of Conferences, EPJ Web of Conferences, 169, Mar. 2018 , Refereed
    Summary:© The Authors, published by EDP Sciences, 2018. Multi-nucleon transfer channels of the reactions of18O+232Th,18O+238U,18O+248Cm were used to measure fission-fragment mass distribution for various nuclides and their excitation energy dependence. Predominantly asymmetric fission is observed at low excitation energies for all the studied cases, with an increase of the symmetric fission towards high excitation energies. Experimental data are compared with predictions of the fluctuation-dissipation model, where effects of multi-chance fission (neutron evaporation prior to fission) was introduced. It was shown that a reliable understanding of the observed fission fragment mass distributions can be obtained only invoking multi-chance fissions.
  • Study of fission using multi-nucleon transfer reactions, Nishio Katsuhisa, Hirose Kentaro, Vermeulen Mark, Makii Hiroyuki, Orlandi Riccardo, Tsukada Kazuaki, Asai Masato, Toyoshima Atsushi, Sato Tetsuya K, Nagame Yuichiro, Chiba Satoshi, Aritomo Yoshihiro, Tanaka Shouya, Ohtsuki Tsutomu, Tsekhanovich Igor, Petrache Costel M, Andreyev Andrei, SCIENTIFIC WORKSHOP ON NUCLEAR FISSION DYNAMICS AND THE EMISSION OF PROMPT NEUTRONS AND GAMMA RAYS (THEORY-4), SCIENTIFIC WORKSHOP ON NUCLEAR FISSION DYNAMICS AND THE EMISSION OF PROMPT NEUTRONS AND GAMMA RAYS (THEORY-4), 169, 2018 , Refereed
  • Study of fission using multi-nucleon transfer reactions, Katsuhisa Nishio, Kentaro Hirose, Vermeulen Mark, Hiroyuki Makii, Riccardo Orlandi, Kazuaki Tsukada, Masato Asai, Atsushi Toyoshima, Tetsuya K. Sato, Yuichiro Nagame, Satoshi Chiba, Yoshihiro Aritomo, Shouya Tanaka, Tsutomu Ohtsuki, Igor Tsekhanovich, Costel M. Petrache, Andrei Andreyev, Andrei Andreyev, EPJ Web of Conferences, EPJ Web of Conferences, 163, Nov. 2017 , Refereed
    Summary:© The Authors, published by EDP Sciences, 2017. It is shown that multi-nucleon transfer reaction is a powerful tool to study fission of exotic neutronrich actinide nuclei, which cannot be accessed by particle-capture or heavy-ion fusion reactions. In this work, multi-nucleon transfer channels of the reactions of18O+232Th,18O+238U,18O+248Cm, and18O+237Np were used to measure fission-fragment mass distribution for each transfer channel. Predominantly asymmetric fission is observed at low excitation energies for all the studied cases, with an increase of the symmetric fission towards high excitation energies. Experimental data are compared with predictions of the fluctuation-dissipation model, where effects of multi-chance fission (neutron evaporation prior to fission) was introduced. It is shown that mass-asymmetric structure remaining at high excitation energies originates from low-excited and less neutronrich excited nuclei due to higher-order chance fissions.
  • Estimation of evaporation residue cross section for the synthesis of superheavy nuclei, Yoshihiro Aritomo, Shyou Sawada, Nur Liyana, Jin Nakagawa, Shoya Tanaka, Ken'Etsu Hanabusa, EPJ Web of Conferences, EPJ Web of Conferences, 163, Nov. 2017 , Refereed
    Summary:© The Authors, published by EDP Sciences, 2017. To estimate the evaporation residue cross section of superheavy nuclei, we clarify the parameter dependence of the models. At the first attempt, we focus our attention on the parameters of the statistical model, and investigate the parameter dependence of the survival probability. Then we discuss the the evaporation residue cross section for each parameter.
  • Experimental fission study using multi-nucleon transfer reactions, Nishio Katsuhisa, Hirose Kentaro, Leguillon Romain, Makii Hiroyuki, Orlandi Riccardo, Tsukada Kazuaki, Smallcombe James, Chiba Satoshi, Aritomo Yoshihiro, Tanaka Shouya, Ohtsuki Tsutomu, Tsekhanovich Igor, Petrache Costel M, Andreyev Andrei, ND 2016: INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND 2016: INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, 146, 2017 , Refereed
  • Fission fragments mass distributions of nuclei populated by the multinucleon transfer channels of the18O + 232Th reaction, R. Léguillon, K. Nishio, K. Hirose, H. Makii, I. Nishinaka, R. Orlandi, K. Tsukada, J. Smallcombe, J. Smallcombe, S. Chiba, Y. Aritomo, T. Ohtsuki, R. Tatsuzawa, N. Takaki, N. Tamura, S. Goto, I. Tsekhanovich, C. M. Petrache, A. N. Andreyev, A. N. Andreyev, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 761, 125 - 130, Oct. 2016 , Refereed
    Summary:© 2016 The Author(s) It is shown that the multinucleon transfer reactions is a powerful tool to study fission of exotic neutron-rich actinide nuclei, which cannot be accessed by particle-capture or heavy-ion fusion reactions. In this work, multinucleon transfer channels of the18O + 232Th reaction are used to study fission of fourteen nuclei231,232,233,234Th,232,233,234,235,236Pa, and234,235,236,237,238U. Identification of fissioning nuclei and of their excitation energy is performed on an event-by-event basis, through the measurement of outgoing ejectile particle in coincidence with fission fragments. Fission fragment mass distributions are measured for each transfer channel, in selected bins of excitation energy. In particular, the mass distributions of231,234Th and234,235,236Pa are measured for the first time. Predominantly asymmetric fission is observed at low excitation energies for all studied cases, with a gradual increase of the symmetric mode towards higher excitation energy. The experimental distributions are found to be in general agreement with predictions of the fluctuation–dissipation model.
  • The transport coefficient of collective motion within the two-center shell model shape parameterization, Ivanyuk Fedir, Chiba Satoshi, Aritomo Yoshihiro, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 53(6), 737 - 748, May 2016 , Refereed
  • A Comprehensive Approach to Determination of Nuclear Data of Unstable Nuclei, Satoshi Chiba, Satoshi Chiba, Katsuhisa Nishio, Yohihiro Aritomo, Hiroyuki Koura, Osamu Iwamoto, Hiroyuki Makii, Ichiro Nishinaka, Kentaro Hirose, EPJ Web of Conferences, EPJ Web of Conferences, 106, Feb. 2016 , Refereed
    Summary:© Owned by the authors, published by EDP Sciences, 2016. A comprehensive approach to determine nuclear data of unstable nuclei will be described. It consists of a measurement of fission and capture cross sections, mass distribution of fission fragments (independent fission yields) and number of prompt fission neutrons by the method of surrogate reactions. A multi-dimensional Langevin model is being developed to estimate the independent fission yields theoretically. Furthermore, the β decay properties of the fission fragments, almost all are neutron-rich unstable nuclei, are investigated systematically by improving the gross theory of β decay, which will yield information on the decay heat and delayed-neutron data.
  • Dynamical approach to isotopic-distribution of fission fragments from actinide nuclei, Ishizuka Chikako, Chiba Satoshi, Karpov Alexander V, Aritomo Yoshihiro, CNR*15 - 5TH INTERNATIONAL WORKSHOP ON COMPOUND-NUCLEAR REACTIONS AND RELATED TOPICS, CNR*15 - 5TH INTERNATIONAL WORKSHOP ON COMPOUND-NUCLEAR REACTIONS AND RELATED TOPICS, 122, 2016 , Refereed
  • Independent fission yields studied based on Langevin equation, Aritomo Yoshihiro, Chiba Satoshi, Nishio Katsuhisa, PROGRESS IN NUCLEAR ENERGY, PROGRESS IN NUCLEAR ENERGY, 85, 568 - 572, Nov. 2015 , Refereed
  • The Scission Point Configuration and the Multiplicity of Prompt Neutrons, F. A. Ivanyuk, F. A. Ivanyuk, S. Chiba, Y. Aritomo, Physics Procedia, Physics Procedia, 64, 28 - 33, Jan. 2015 , Refereed
    Summary:© 2015 The Authors. We defined the optimal shape which fissioning nuclei attain just before the scission and calculated the deformation energy as function of the mass asymmetry and elongation at the scission point. The calculated deformation energy is used in quasi-static approximation for estimation of the mass distribution of fission fragments, total kinetic and excitation energy of fission fragments, and the total number of prompt neutrons. The calculated results reproduce rather well the experimental data on the position of the peaks in the mass distribution of fission fragments, the total kinetic and excitation energy of fission fragments. The calculated value of neutron multiplicitiy is somewhat larger than experimental results.
  • A comprehensive approach to estimate delayed-neutron data of actinides and minor-actinides, Chiba Satoshi, Nishio Katsuhisa, Aritomo Yoshihiro, Koura Hiroyuki, Iwamoto Osamu, Kugo Teruhiko, FOURTH INTERNATIONAL SYMPOSIUM ON INNOVATIVE NUCLEAR ENERGY SYSTEMS (INES-4), FOURTH INTERNATIONAL SYMPOSIUM ON INNOVATIVE NUCLEAR ENERGY SYSTEMS (INES-4), 71, 205 - 212, 2015 , Refereed
  • Scission-point configuration within the two-center shell model shape parameterization, F. A. Ivanyuk, F. A. Ivanyuk, S. Chiba, Y. Aritomo, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 90, Nov. 2014 , Refereed
    Summary:© 2014 American Physical Society. Within the two-center shell model parameterization we defined the optimal shape that fissioning nuclei attain just before the scission and calculated the total deformation energy (liquid-drop part plus the shell correction) as a function of the mass asymmetry and elongation at the scission point. The three minima corresponding to one mass-symmetric and two mass-asymmetric peaks in the mass distribution of fission fragments are found in the deformation energy at the scission point. The calculated deformation energy is used in a quasistatic approximation for the estimation of the total kinetic and excitation energies of fission fragments and the total number of emitted prompt neutrons. The calculated results reproduce rather well the experimental data on the position of the peaks in the mass distribution of fission fragments, and the total kinetic and excitation energies of fission fragments. The calculated value of neutron multiplicity is somewhat larger than experimental results.
  • Study of heavy-ion induced fission for heavy-element synthesis, K. Nishio, H. Ikezoe, S. Hofmann, S. Hofmann, F. P. Heßberger, D. Ackermann, S. Antalic, Y. Aritomo, Y. Aritomo, V. F. Comas, V. F. Comas, Ch E. Düllman, A. Gorshkov, R. Graeger, S. Heinz, J. A. Heredia, J. A. Heredia, K. Hirose, K. Hirose, J. Khuyagbaatar, B. Kindler, I. Kojouharov, B. Lommel, H. Makii, R. Mann, S. Mitsuoka, Y. Nagame, I. Nishinaka, T. Ohtsuki, A. G. Popeko, S. Saro, M. Schädel, A. Türler, Y. Wakabayashi, Y. Wakabayashi, Y. Watanabe, A. Yakushev, A. V. Yeremin, EPJ Web of Conferences, EPJ Web of Conferences, 66, Apr. 14 2014
    Summary:Fission fragment mass distributions were measured in heavy-ion induced fissions using 238U target nucleus. The measured mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their incident energy dependence. Fusion probability was determined in the analysis, and the values were consistent with those determined from the evaporation residue cross sections. © Owned by the authors, published by EDP Sciences, 2014.
  • Fission dynamics at low excitation energy, Y. Aritomo, S. Chiba, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 90, Oct. 12 2013
    Summary:The origin of mass asymmetry in the fission of uranium at a low excitation
    energy is clarified by a trajectory analysis of the Langevin equation. The
    positions of the peaks in the mass distribution of fission fragments are mainly
    determined by fission saddle points originating from the shell correction
    energy. The widths of the peaks, on the other hand, result from a shape
    fluctuation around the scission point caused by the random force in the
    Langevin equation. We found that a random vibration in the oblate direction of
    fissioning fragments is essential for the fission process. According to this
    picture, fission does not occur with continuous stretching in the prolate
    direction, similarly to that observed in starch syrup. This is expected to lead
    to a new viewpoint of fission dynamics and the splitting mechanism.
  • Fission process of low excited nuclei with Langevin approach, Y. Aritomo, S. Chiba, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 88, May 27 2013
    Summary:Fragment mass distributions from the fission of U and Pu isotopes at low
    excitation energies are studied using a dynamical model based on the
    fluctuation-dissipation theorem formulated as Langevin equations. The present
    calculations reproduced the overall trend of the asymmetric mass distribution
    without parameter adjustment for the first time using the Langevin approach.
    The Langevin trajectories show a complicated time evolution on the potential
    surface, which causes the time delay of fission, showing that dynamical
    treatment is vital. It was found that the shell effect of the potential energy
    landscape has a dominant role in determining the mass distribution, although it
    is rather insensitive to the strength of dissipation. Nevertheless, it is
    essential to include the effect of dissipation, since it has a crucial role in
    giving "fluctuation" to Langevin trajectories as well as for explaining the
    multiplicities of pre-scission neutrons as the excitation energy increases.
    Therefore, the present approach can serve as a basis for more refined analysis.
  • In-beam fissio study at JAEA for heavy element synthesis, K. Nishio, H. Ikezoe, S. Hofmann, S. Hofmann, D. Ackermann, Y. Aritomo, Y. Aritomo, V. F. Comas, Ch E. Düllmann, S. Heinz, J. A. Heredia, F. P. Heßberger, K. Hirose, J. Khuyagbaatar, B. Kindler, I. Kojouharov, B. Lommel, M. Makii, R. Mann, S. Mitsuoka, I. Nishinaka, T. Ohtsuki, S. Saro, M. Schädel, A. G. Popeko, A. Türler, Y. Wakabayashi, Y. Watanabe, A. Yakushev, A. Yeremin, AIP Conference Proceedings, AIP Conference Proceedings, 1524, 68 - 72, May 06 2013
    Summary:Fission fragment mass distributions were measured in the heavy-ion induced fission using 238U target nucleus. The mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their incident energy dependence. Fusion probability was determined in the analysis. Evaporation residue cross sections were calculated with a statistical model in the reactions of 30Si+238U and 34S+238U using the obtained fusion probability in the entrance channel. The results agree with the measured cross sections of 263,264Sg and 267,268Hs, produced by 30Si+ 238U and 34S+238U, respectively. It is also suggested that the sub-barrier energies can be used for heavy element synthesis. © 2013 AIP Publishing LLC.
  • Dynamical approach to heavy-ion induced fusion using actinide target, Y. Aritomo, K. Hagino, S. Chiba, K. Nishio, AIP Conference Proceedings, AIP Conference Proceedings, 1491, 303 - 306, Dec. 01 2012
    Summary:To treat heavy-ion reactions using actinide target nucleus, we propose a model which takes into account the coupling to the collective states of interacting nuclei in the penetration of the Coulomb barrier and the dynamical evolution of nuclear shape from the contact configuration. A fluctuation-dissipation model (Langevin equation) was applied in the dynamical calculation, where effect of nuclear orientation at the initial impact on the prolately deformed target nucleus was considered. Using this model, we analyzed the experimental data for the mass distribution of fission fragments (MDFF) in the reaction of 36S+238U at several incident energies. Fusion-fission, quasifission and deep-quasi-fission are separated as different trajectories on the potential energy surface. We estimated the fusion cross section of the reaction. © 2012 American Institute of Physics.
  • Dynamical approach to fusion-fission process in superheavy mass region, Y. Aritomo, Y. Aritomo, D. J. Hinde, A. Wakhle, R. Du Rietz, M. Dasgupta, K. Hagino, S. Chiba, S. Chiba, K. Nishio, EPJ Web of Conferences, EPJ Web of Conferences, 35, Dec. 01 2012
    Summary:In order to describe heavy-ion fusion reactions around the Coulomb barrier with an actinide target nucleus, we propose a model which combines the coupled-channels approach and a fluctuation-dissipation model for dynamical calculations. This model takes into account couplings to the collective states of the interacting nuclei in the penetration of the Coulomb barrier and the subsequent dynamical evolution of a nuclear shape from the contact configuration. In the fluctuation-dissipation model with a Langevin equation, the effect of nuclear orientation at the initial impact on the prolately deformed target nucleus is considered. Fusion-fission, quasi-fission and deep quasi-fission are separated as different Langevin trajectories on the potential energy surface. Using this model, we analyze the experimental data for the mass distribution of fission fragments (MDFF) in the reaction of 36S+ 238U at several incident energies around the Coulomb barrier. © Owned by the authors 2012.
  • Fusion probabilities in the reactions 40 ,48Ca+238U at energies around the Coulomb barrier, K. Nishio, S. Mitsuoka, I. Nishinaka, H. Makii, Y. Wakabayashi, H. Ikezoe, K. Hirose, T. Ohtsuki, Y. Aritomo, Y. Aritomo, S. Hofmann, S. Hofmann, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 86, Sep. 18 2012
    Summary:Fission cross sections and fission fragment mass distributions were measured in the reactions of 40Ca+238U and 48Ca+238U at energies around the Coulomb barrier. Fusion probabilities were calculated based on the fluctuation dissipation model. The measured mass distributions for both reactions showed an asymmetric shape at low incident energies, whereas the distribution changed to a flat shape at higher energies. The variation of the mass distribution is explained by a change of the ratio between fusion and quasifission with nuclear orientation. The calculation reproduced the mass distributions and their energy dependence. The trajectories for fusion-fission were used to determine the fusion probability. Fusion probabilities for both reactions are identical as function of the center-of-mass energy (E c.m.), but they differ when plotted as function of the excitation energy (E *). Evaporation residue cross sections were calculated for the reaction 48Ca+238U using a statistical model and the obtained fusion cross sections as input values. The results are compared to experimental data. © 2012 American Physical Society.
  • Dynamical approach to heavy-ion induced fission using actinide target nuclei at energies around the Coulomb barrier, Y. Aritomo, K. Hagino, K. Nishio, S. Chiba, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 85, Mar. 12 2012
    Summary:In order to describe heavy-ion fusion reactions around the Coulomb barrier
    with an actinide target nucleus, we propose a model which combines the
    coupled-channels approach and a fluctuation-dissipation model for dynamical
    calculations. This model takes into account couplings to the collective states
    of the interacting nuclei in the penetration of the Coulomb barrier and the
    subsequent dynamical evolution of a nuclear shape from the contact
    configuration. In the fluctuation-dissipation model with a Langevin equation,
    the effect of nuclear orientation at the initial impact on the prolately
    deformed target nucleus is considered. Fusion-fission, quasi-fission and deep
    quasi-fission are separated as different Langevin trajectories on the potential
    energy surface. Using this model, we analyze the experimental data for the mass
    distribution of fission fragments (MDFF) in the reactions of
    $^{34,36}$S+$^{238}$U and $^{30}$Si+$^{238}$U at several incident energies
    around the Coulomb barrier. We find that the time scale in the quasi-fission as
    well as the deformation of fission fragments at the scission point are
    different between the $^{30}$Si+$^{238}$U and $^{36}$S+$^{238}$U systems,
    causing different mass asymmetries of the quasi-fission.
  • Spin-dependent observables in surrogate reactions, CHIBA Satoshi, IWAMOTO Osamu, ARITOMO Yoshihiro, Phys Rev C Nucl Phys, Phys Rev C Nucl Phys, 84(5), 054602.1-054602.5, Nov. 2011
  • Spin-dependent observables in surrogate reactions, Satoshi Chiba, Osamu Iwamoto, Yoshihiro Aritomo, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 84, May 17 2011
    Summary:Observables emitted from various spin states in compound U nuclei are
    investigated to validate usefulness of the surrogate reaction method. It was
    found that energy spectrum of cascading $\gamma$-rays and their multiplicities,
    spectrum of evaporated neutrons, and mass-distribution of fission fragments
    show clear dependence on the spin of decaying nuclei. The present results
    indicate that they can be used to infer populated spin distributions which
    significantly affect the decay branching ratio of the compound system produced
    by the surrogate reactions.
  • Research Group for Reactions Involving Heavy Nuclei, CHIBA Satoshi, NISHIO Katsuhisa, MITSUOKA Shinichi, KOURA Hroyuki, NISHINAKA Ichiro, UTSUNO Yutaka, MAKII Hiroyuki, WAKABAYASHI Yasuo, ARITOMO Yoshihiro, OTA Shuya, NAGAYAMA Tatsuro, Ann Rep ASRC, Ann Rep ASRC, 2011, 12, 2011
  • Investigation of fission properties and evaporation residue measurement in the reactions using 238U target nucleus, K. Nishio, H. Ikezoe, S. Hofmann, S. Hofmann, D. Ackermann, S. Antalic, Y. Aritomo, Y. Aritomo, V. F. Comas, V. F. Comas, Ch E. Düllmann, A. Gorshkov, R. Graeger, K. Hagino, S. Heinz, J. A. Heredia, K. Hirose, K. Hirose, J. Khuyagbaatar, B. Kindler, I. Kojouharov, B. Lommel, H. Makii, R. Mann, S. Mitsuoka, Y. Nagame, I. Nishinaka, T. Ohtsuki, A. G. Popeko, S. Saro, M. Schädel, A. Türler, Y. Wakabayashi, Y. Watanabe, A. Yakushev, A. V. Yeremin, EPJ Web of Conferences, EPJ Web of Conferences, 17, Jan. 01 2011
    Summary:© Owned by the authors, published by EDP Sciences, 2011. Fragment mass distributions for fission after full momentum transfer were measured in the reactions of 30Si,34,36 S,31P,40Ar + 238U at bombarding energies around the Coulomb barrier. Mass distributions change significantly as a function of incident beam energy. The asymmetric fission probability increases at sub-barrier energy. The phenomenon is interpreted as an enhanced quasifission probability owing to orientation effects on fusion and/or quasifission. The evaporation residue (ER) cross sections were measured in the reactions of 30Si + 238U and 34S + 238U to obtain information on fusion. In the latter reaction, significant suppression of fusion was implied. This suggests that fission events different from compound nucleus are included in the masssymmetric fragments. The results are supported by a model calculation based on a dynamical calculation using Langevin equation, in which the mass distribution for fusion-fission and quasifission fragments are separately determined.
  • Evidence for quasifission in the sub-barrier reaction of 30Si+238U, K. Nishio, H. Ikezoe, I. Nishinaka, S. Mitsuoka, K. Hirose, T. Ohtsuki, Y. Watanabe, Y. Aritomo, Y. Aritomo, S. Hofmann, S. Hofmann, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 82, Nov. 30 2010
    Summary:Fragment mass distributions for fission after full momentum transfer were measured for the 30Si+238U reaction at bombarding energies around the Coulomb barrier. At energies above the Bass barrier, the mass distributions were Gaussian with mass symmetry. An asymmetric fission channel with mass AL/AH ≈ 90/178 emerged at the sub-barrier energies, where competition between fusion and quasifission was suggested from the evaporation residue (ER) cross section produced in the fusion 30Si+238U. We thus conclude the asymmetric channel is attributed to quasifission. It was supported by a model calculation using the Langevin equation to give the fragment mass distribution, where fusion-fission and quasifission were separated. The observed mass asymmetry for quasifission as well as the calculation is significantly smaller than those observed in actinide targets bombarded with heavier projectiles, which suggests that the system 30Si+238U approaches the shape of the compound nucleus before disintegrating as quasifission. © 2010 The American Physical Society.
  • Analysis of dynamical process with mass distribution of fission fragments using actinide target nuclei, Y. Aritomo, Y. Aritomo, AIP Conference Proceedings, AIP Conference Proceedings, 1224, 356 - 365, Oct. 27 2010
    Summary:We analyzed experimental data obtained for the mass distribution of fission fragments in the reactions 36S+238U and 30Si+238U at several incident energies, which were performed by the JAEA group. Using the dynamical model with the Langevin equation, we precisely investigate the incident energy dependence of the mass distribution of fission fragments. We also consider the fine structures in the mass distribution of fission fragments caused by the nuclear structure at a low incident energy. It is explained why the mass distribution of fission fragments has different features in the two reactions. The fusion cross sections are also estimated. © 2010 American Institute of Physics.
  • A dynamical model of surrogate reactions, Y. Aritomo, S. Chiba, K. Nishio, Phys.Rev.C84:024602,2011, Phys.Rev.C84:024602,2011, 84, Sep. 30 2010
    Summary:A new dynamical model is developed to describe the whole process of surrogate
    reactions; transfer of several nucleons at an initial stage, thermal
    equilibration of residues leading to washing out of shell effects and decay of
    populated compound nuclei are treated in a unified framework. Multi-dimensional
    Langevin equations are employed to describe time-evolution of collective
    coordinates with a time-dependent potential energy surface corresponding to
    different stages of surrogate reactions. The new model is capable of
    calculating spin distributions of the compound nuclei, one of the most
    important quantity in the surrogate technique. Furthermore, various observables
    of surrogate reactions can be calculated, e.g., energy and angular distribution
    of ejectile, and mass distributions of fission fragments. These features are
    important to assess validity of the proposed model itself, to understand
    mechanisms of the surrogate reactions and to determine unknown parameters of
    the model. It is found that spin distributions of compound nuclei produced in
    $^{18}$O+$^{238}$U $\rightarrow ^{16}$O+$^{240*}$U and $^{18}$O+$^{236}$U
    $\rightarrow ^{16}$O+$^{238*}$U reactions are equivalent and much less than
    10$\hbar$, therefore satisfy conditions proposed by Chiba and Iwamoto (PRC 81,
    044604(2010)) if they are used as a pair in the surrogate ratio method.
  • Nuclear orientation in the reaction S34+U238 and synthesis of the new isotope Hs268, K. Nishio, S. Hofmann, S. Hofmann, F. P. Heßberger, D. Ackermann, S. Antalic, Y. Aritomo, Y. Aritomo, V. F. Comas, Ch E. Düllmann, A. Gorshkov, R. Graeger, K. Hagino, S. Heinz, J. A. Heredia, K. Hirose, H. Ikezoe, J. Khuyagbaatar, B. Kindler, I. Kojouharov, B. Lommel, R. Mann, S. Mitsuoka, Y. Nagame, I. Nishinaka, T. Ohtsuki, A. G. Popeko, S. Saro, M. Schädel, A. Türler, Y. Watanabe, A. Yakushev, A. V. Yeremin, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 82, Aug. 31 2010
    Summary:The synthesis of isotopes of the element hassium was studied using the reaction S34+U238→Hs272*. At a kinetic energy of 163.0MeV in the center-of-mass system we observed one α-decay chain starting at the isotope Hs267. The cross section was 1.8-1.5+4.2 pb. At 152.0MeV one decay of the new isotope Hs268 was observed. It decays with a half-life of 0.38-0.17+1.8 s by 9479±16keV α-particle emission. Spontaneous fission of the daughter nucleus Sg264 was confirmed. The measured cross section was 0.54-0.45+1.3 pb. In-beam measurements of fission-fragment mass distributions were performed to obtain information on the fusion probability at various orientations of the deformed target nucleus. The distributions changed from symmetry to asymmetry when the beam energy was changed from above-barrier to sub-barrier values, indicating orientation effects on fusion and/or quasifission. It was found that the distribution of symmetric mass fragments originates not only from fusion-fission, but has a strong component from quasifission. The result was supported by a calculation based on a dynamical description using the Langevin equation, in which the mass distributions for fusion-fission and quasifission fragments were separately determined. © 2010 The American Physical Society.
  • Fusion-fission and quasi-fission processes in reactions using actinide target nuclei, Yoshihiro Aritomo, Yoshihiro Aritomo, International Journal of Modern Physics E, International Journal of Modern Physics E, 19, 813 - 824, Jun. 01 2010
    Summary:We analyzed experimental data obtained for the mass distribution of fission fragments in the reactions 36S+238U and 30Si+238U at several incident energies, which were performed by the JAEA group. Using the dynamical model with the Langevin equation, we precisely investigate the incident energy dependence of the mass distribution of fission fragments. We also consider the fine structures in the mass distribution of fission fragments caused by the nuclear structure at a low incident energy. It is explained why the mass distribution of fission fragments has different features in the two reactions. The fusion cross sections are also estimated. © 2010 World Scientific Publishing Company.
  • Analysis of dynamical process with mass distribution of fission fragmentin heavy ion reactions, Y. Aritomo, Y. Aritomo, EPJ Web of Conferences, EPJ Web of Conferences, 2, Jan. 01 2010
    Summary:© 2010 Owned by the authors, published by EDP Sciences. We analyzed experimental data obtained for the mass distribution of fission fragments in the reactions 36S+238U and 30Si+238U at several incident energies, which were performed by the JAEA group. Using the dynamical model with the Langevin equation, we precisely investigate the incident energy dependence of the mass distribution of fission fragments. We also consider the fine structures in the mass distribution of fission fragments caused by the nuclear structure at a low incident energy. It is explained why the mass distribution of fission fragments has different features in the two reactions. The fusion cross sections are also estimated.
  • Analysis of dynamical processes using the mass distribution of fission fragments in heavy-ion reactions, Y. Aritomo, Y. Aritomo, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 80, Dec. 04 2009
    Summary:We analyze experimental data obtained for the mass distribution of fission fragments in the reactions S36+U238 and Si30+U238 at several incident energies, which were performed by the Japan Atomic Energy Agency (JAEA) group. The analysis of the mass distribution of fission fragments is a powerful tool for understanding the mechanism of the reaction in the heavy and superheavy-mass regions. Using the dynamical model with the Langevin equation, we precisely investigate the incident energy dependence of the mass distribution of fission fragments. This study is the first attempt to treat such experimental data systematically. We also consider the fine structures in the mass distribution of fission fragments caused by the nuclear structure at a low incident energy. It is explained why the mass distribution of fission fragments has different features in the two reactions. The fusion cross sections are also estimated. © 2009 The American Physical Society.
  • Fusion-fission dynamics in superheavy mass region, Yoshihiro Aritomo, International Journal of Modern Physics E, International Journal of Modern Physics E, 18, 2145 - 2149, Nov. 01 2009
    Summary:In heavy nucleus collision experiments, the fusion-fission cross section is derived from counting mass-symmetric fission events. However, a discrepancy exists between the experimental and theoretical estimations of the fusion cross section. We attempt to clarify the origin of the discrepancy and remove it by performing a dynamical calculation. The trajectory calculation has been performed in three-dimensional coordinate space with the Langevin equation. © 2009 World Scientific Publishing Company.
  • Analysis of mass distribution of fission fragment in superheavy mass region, Y. Aritomo, AIP Conference Proceedings, AIP Conference Proceedings, 1120, 27 - 31, Jul. 22 2009
    Summary:Recently our FLNR theoretical group completes a calculation model to treat all reaction processes in heavy and superheavy mass region, which is so called "Unified model". Using a lot of available experimental data, we verify the validity of our model and establish a reliable model to describe the whole reaction process. As examples of the application of our model, we discuss two cases that are quasi-fission process and deep inelastic collision. We show the calculation results of the mass distribution of fission fragments in the reaction 36S + 236U. Also, we discuss the possibility for the production of new heavy neutron-rich nuclei in the low-energy multi-neutron transfer process. © 2009 American Institute of Physics.
  • Time-dependent potential energy for fusion and fission processes, A. V. Karpov, V. I. Zagrebaev, Y. Aritomo, M. A. Naumenko, W. Greiner, Dynamical Aspects of Nuclear Fission - Proceedings of the 6th International Conference, DANF 2006, Dynamical Aspects of Nuclear Fission - Proceedings of the 6th International Conference, DANF 2006, 112 - 123, Jan. 01 2008
    Summary:The problem of description of low-energy nuclear dynamics and derivation of multi-dimensional potential energy surface depending on several collective degrees of freedom is discussed. Multi-dimensional adiabatic potential is constructed basing on extended version of the two-center shell model. It has correct asymptotic value and height of the Coulomb barrier in the entrance channel (fusion) and appropriate behavior in the exit one, giving required mass and energy distributions of reaction products and fission fragments. Explicit time-dependence of the driving potential was introduced in order to take into account difference of diabatic and adiabatic regimes of motion of nuclear system at above-barrier energies and also difference of nuclear shapes in fusion and fission channels (neck formation). Derived driving potential is proposed to be used for unified analysis of the processes of deep-inelastic scattering, fusion and fission at low-energy collisions of heavy ions. © 2008 World Scientific Publishing Co. Pte. Ltd.
  • Dynamics of capture quasifission and fusion-fission competition, L. Stuttgé, C. Schmitt, O. Dorvaux, N. Rowley, T. Materna, F. Hanappe, V. Bouchat, Y. Aritomo, A. Bogatchev, I. Itkis, M. Itkis, M. Jandel, G. Knyajeva, J. Kliman, E. Kozulin, N. Kondratiev, L. Krupa, Y. Oganessian, I. Pokrovski, E. Prokhorova, V. Voskresenski, N. Amar, S. Grévy, J. Péter, G. Giardina, Dynamical Aspects of Nuclear Fission - Proceedings of the 6th International Conference, DANF 2006, Dynamical Aspects of Nuclear Fission - Proceedings of the 6th International Conference, DANF 2006, 22 - 35, Jan. 01 2008
    Summary:An overview of the different experimental approaches to disentangle the quasi-fission and the fusion-fission processes in the heavy and superheavy mass region is presented. Indeed the separation of these two processes is essential in order to get a correct and complete insight of the mechanisms leading to the synthesis of superheavy elements. The importance of the neutron information through a new analysis protocol is detailed. Future perspectives are presented. © 2008 World Scientific Publishing Co. Pte. Ltd.
  • Possibility of synthesizing doubly magic superheavy nuclei, Y. Aritomo, M. Ohta, F. Hanappe, T. Materna, L. Stuttgé, O. Dorvaux, Dynamical Aspects of Nuclear Fission - Proceedings of the 6th International Conference, DANF 2006, Dynamical Aspects of Nuclear Fission - Proceedings of the 6th International Conference, DANF 2006, 155 - 166, Jan. 01 2008
    Summary:Fusion-fission process in superheavy mass region is investigated on the basis of the fluctuation-dissipation dynamics. We analyze the trajectory in three-dimensional coordinate space with the Langevin equation. To investigate the fusion-fission process more precisely, we propose to take into account the pre-scission neutron multiplicity in connection with fission fragments. For the survival process, we apply the dynamical model instead of the statistical model. The possibility of synthesizing a doubly magic superheavy nucleus, 298114184, is investigated taking into account the temperature dependence of the potential energy owing to neutron emission. © 2008 World Scientific Publishing Co. Pte. Ltd.
  • Roles of shell effects in fusion process for synthesis of superheavy elements, Y. Aritomo, AIP Conference Proceedings, AIP Conference Proceedings, 912, 266 - 275, Sep. 25 2007
    Summary:The effects of shell correction energy for fusion process are investigated on the basis of the fluctuation-dissipation dynamics. In the superheavy mass region, shell correction energy plays a very important role and enhances the fusion probability when the colliding partner has a strong shell structure. By analyzing the trajectory in three-dimensional coordinate space with the Langevin equation, we reveal the mechanism of the enhancement of the fusion probability caused by 'cold fusion valleys' and the temporary pocket which appears in fusion process. © 2007 American Institute of Physics.
  • Potential energy of heavy nuclear system in low-energy fusion-fission processes, A. V. Karpov, V. I. Zagrebaev, Y. Aritomo, M. A. Naumenko, W. Greiner, AIP Conference Proceedings, AIP Conference Proceedings, 912, 286 - 298, Sep. 24 2007
    Summary:The problem of description of low-energy nuclear dynamics and derivation of multi-dimensional potential energy surface depending on several collective degrees of freedom is discussed. Multi-dimensional adiabatic potential is constructed basing on extended version of the two-center shell model. It has correct asymptotic value and height of the Coulomb barrier in the entrance channel (fusion) and appropriate behavior in the exit one, giving required mass and energy distributions of reaction products and fission fragments. Explicit time-dependence of the driving potential was introduced in order to take into account difference of diabatic and adiabatic regimes of motion of nuclear system at above-barrier energies and also difference of nuclear shapes in fusion and fission channels (neck formation). Derived driving potential is proposed to be used for unified analysis of the processes of deep-inelastic scattering, fusion and fission at low-energy collisions of heavy ions. © 2007 American Institute of Physics.
  • Potential energy of a heavy nuclear system in fusion-fission processes, V. Zagrebaev, A. Karpov, Y. Aritomo, M. Naumenko, W. Greiner, Physics of Particles and Nuclei, Physics of Particles and Nuclei, 38, 469 - 491, Jul. 01 2007
    Summary:We discuss the problem of description of low-energy nuclear dynamics and the derivation of a multi-dimensional potential energy surface that depends on several collective degrees of freedom and allows a unified analysis of deep inelastic scattering, fusion, and fission processes. A unified description is required due to the strong coupling and significant overlapping of these reaction channels in heavy nuclear systems, which are used, in particular, for synthesis of superheavy elements. The multidimensional adiabatic potential is derived based on an extended versio of the two-center shell model. This model leads to a correct asymptotic value and height of the Coulomb barrier in the entrance channel (fusion), and appropriate behavior in the exit channel, giving the required mass and energy distributions of reaction products and fission fragments. The derived driving potential is proposed to be applied in a consistent dynamic analysis of low-energy interactions of heavy nuclei. © 2007 Pleiades Publishing, Ltd.
  • A reassessment of surface friction model for maximum cold fusion reactions in superheavy mass region, A. Fukushima, A. Nasirov, Y. Aritomo, T. Wada, M. Ohta, AIP Conference Proceedings, AIP Conference Proceedings, 891, 443 - 446, Apr. 08 2007
    Summary:We have made a study on the capture process of 40,48Ca+ 208Pb systems with a dynamical approach based on the surface friction model. The deformation of the nuclei due to the mutual excitation is taken into account. We have calculated the capture cross sections for several values of the friction coefficients. It was shown that, in the cold fusion reactions, the friction parameters of the surface friction model needs to be reexamined. © 2007 American Institute of Physics.
  • Fission fragment mass distribution for nuclei in the r-process region, S. Tatsuda, K. Hashizume, T. Wada, M. Ohta, K. Sumiyoshi, K. Sumiyoshi, K. Otsuki, T. Kajino, T. Kajino, T. Kajino, H. Koura, S. Chiba, Y. Aritomo, AIP Conference Proceedings, AIP Conference Proceedings, 891, 423 - 426, Apr. 04 2007
    Summary:The fission fragment mass distribution is estimated theoretically on about 2000 nuclides which might have a critical role on the r-process nucleosynthesis through fission (Z>85). The mass distribution of fission fragment is derived by considering the location and the depth of valleys of potential energy surface near scission point of nuclei calculated by means of the liquid drop model with the shell energy correction by the Two-Center shell model. The guiding principle of determining the fission mass asymmetry is the behavior of the fission paths from the saddle to the scission point given by the Langevin calculation. © 2007 American Institute of Physics.
  • Fusion hindrance and roles of shell effects in superheavy mass region, Y. Aritomo, Nucl.Phys. A780 (2006) 222-246, Nucl.Phys. A780 (2006) 222-246, 780, 222 - 246, Sep. 19 2006
    Summary:We present the first attempt of systematically investigating the effects of
    shell correction energy for a dynamical process, which includes fusion,
    fusion-fission and quasi-fission processes. In the superheavy mass region, for
    the fusion process, shell correction energy plays a very important role and
    enhances the fusion probability when the colliding partner has a strong shell
    structure. By analyzing the trajectory in three-dimensional coordinate space
    with the Langevin equation, we reveal the mechanism of the enhancement of the
    fusion probability caused by `cold fusion valleys'. The temperature dependence
    of shell correction energy is considered.
  • Possibility of synthesizing doubly closed superheavy nucleus, Y. Aritomo, Phys.Rev.C75:024602,2007, Phys.Rev.C75:024602,2007, 75, Sep. 16 2006
    Summary:The possibility of synthesizing a doubly magic superheavy nucleus,
    $^{298}114_{184}$, is investigated on the basis of fluctuation-dissipation
    dynamics. In order to synthesize this nucleus, we must generate more
    neutron-rich compound nuclei because of the neutron emissions from excited
    compound nuclei. The compound nucleus $^{304}114$ has two advantages to
    achieving a high survival probability. First, because of small neutron
    separation energy and rapid cooling, the shell correction energy recovers
    quickly. Secondly, owing to neutron emissions, the neutron number of the
    nucleus approaches that of the double closed shell and the nucleus obtains a
    large fission barrier. Because of these two effects, the survival probability
    of $^{304}114$ does not decrease until the excitation energy $E^{*}= 50$ MeV.
    These properties lead to a rather high evaporation reside cross section.
  • Fusion Hindrance and the Role of Shell Effects in the Superheavy Mass Region, Y. Aritomo, AIP Conference Proceedings, AIP Conference Proceedings, 853, 259 - 264, Sep. 14 2006
    Summary:We present the first attempt of the systematical investigation about the
    effects of shell correction energy for dynamical processes, which include
    fusion, fusion-fission and quasi-fission processes. In the superheavy mass
    region, for the fusion process, the shell correction energy plays a very
    important role and enhances the fusion probability, when the colliding partner
    has strong shell structure. By analyzing the trajectory in the
    three-dimensional coordinate space with a Langevin equation, we reveal the
    mechanism of the enhancement of the fusion probability caused by shell effects.
  • Pre-scission neutron multiplicity associated with the dynamical process in superheavy mass region, Y. Aritomo, M. Ohta, F. Hanappe, J.Phys. G32 (2006) 2245-2260, J.Phys. G32 (2006) 2245-2260, 32, 2245 - 2259, Sep. 14 2006
    Summary:The fusion-fission process accompanied by neutron emission is studied in the
    superheavy-mass region on the basis of the fluctuation-dissipation model
    combined with a statistical model. The calculation of the trajectory or the
    shape evolution in the deformation space of the nucleus with neutron emission
    is performed. Each process (quasi-fission, fusion-fission, and deep
    quasi-fission processes) has a characteristic travelling time from the point of
    contact of colliding nuclei to the scission point. These dynamical aspects of
    the whole process are discussed in terms of the pre-scission neutron
    multiplicity, which depends on the time spent on each process. We have
    presented the details of the characteristics of our model calculation in the
    reactions $^{48}$Ca+$^{208}$Pb and $^{48}$Ca+$^{244}$Pu, and shown how the
    structure of the distribution of pre-scission neutron multiplicity depends on
    the incident energy.
  • Role of the nuclear shell structure and orientation angles of deformed reactants in complete fusion, A. K. Nasirov, A. K. Nasirov, Y. Aritomo, Y. Aritomo, A. Fukushima, M. Ohta, T. Wada, G. Giardina, G. Mandaglio, A. Muminov, R. K. Utamuratov, R. K. Utamuratov, International Journal of Modern Physics E, International Journal of Modern Physics E, 15, 311 - 317, Mar. 01 2006
    Summary:The dependence of the capture and fusion excitation functions on the nuclear shell structure and initial orientation angles of the symmetry axis of the deformed projectile- and target-nucleus are explored by the dynamical model based on the dinuclear system concept and Langevin calculations. The fusion cross sections for 16O+238U and 60Ni+ 154Sm reactions obtained by averaging of the results for the all orientation angles are in good agreement with the experimental data. The capture and fusion cross sections for the 16O+238U reaction are nearly the same while those are different for the 60Ni+ 154Sm reaction due to presence of the hindrance to fusion as quasifission. The largest of the fusion cross section for the orientation angles of the reactants in the range 60° < ai < 90° (A) in comparison with that for angles 0° < ai < 30° (B) was explained by the increase of the quasiflssion contribution in the last case (B). The physical reason of this phenomenon is connected by the largest of the intrinsic fusion barrier B*fus in case (B) than that for the case (A). The observed difference between the excitation functions of evaporation residues for the 86Kr + 130Xe and 124Sn + 92Zr reactions is explained by the difference between the B*fus values which depend on the nuclear shell corrections. © World Scientific Publishing Company.
  • The role of orientation of nucleus symmetry axis in fusion dynamics, Avazbek Nasirov, Avazbek Nasirov, Akira Fukushima, Yuka Toyoshima, Yoshihiro Aritomo, Yoshihiro Aritomo, Akhtam Muminov, Shuhrat Kalandarov, Ravshanbek Utamuratov, Nuclear Physics A, Nuclear Physics A, 759, 342 - 369, Sep. 19 2005
    Summary:The dependence of the fusion excitation function on the orientation angles of the symmetry axis of deformed projectile- and target-nucleus relative to the beam direction is studied. The averaged over all orientations values of the fusion-fission cross sections obtained for 16O + 238U and 60Ni + 154Sm reactions are compared with the experimental data. The capture and fusion cross sections for the 16O + 238U reaction are nearly the same while those are different for the 60Ni + 154Sm reaction due to sufficient contribution of the quasifission events. The large values of the fusion cross section are obtained in the range 60° < αi < 90° of the orientation angles of the projectile- and target-nucleus. This phenomenon is explained by the dependence of the intrinsic fusion and quasifission barriers on the orientation angles of reactants. © 2005 Elsevier B.V. All rights reserved.
  • Analysis of fusion-fission dynamics by pre-scission neutron emission in 58Ni+208Pb system, Y. Aritomo, M. Ohta, T. Materna, F. Hanappe, O. Dorvaux, L. Stuttge, Nuclear Physics A, Nuclear Physics A, 759, 309 - 326, Sep. 19 2005
    Summary:We analyzed the experimental data of the pre-scission neutron multiplicity in connection with fission fragments in the reaction 58Ni + 208Pb at the incident energy corresponding to the excitation energy of the compound nucleus E* = 185.9 MeV, which was performed by DéMoN group. The relation between the pre-scission neutron multiplicity and each reaction process having different reaction time is investigated. In order to study the fusion-fission process accompanied by neutron emission, the fluctuation-dissipation model combined with a statistical model is employed. It is found that the fusion-fission process and the quasi-fission process are clearly distinguished in correlation with the pre-scission neutron multiplicity. © 2005 Elsevier B.V. All rights reserved.
  • Origin of the drastic decrease of fusion probability in superheavy mass region, Y. Aritomo, M. Ohta, Nucl.Phys. A764 (2006) 149-159, Nucl.Phys. A764 (2006) 149-159, 764, 149 - 159, Sep. 06 2005
    Summary:The fusion-fission process in the superheavy mass region is studied
    systematically by solving the time evolution of nuclear shape in
    three-dimensional deformation space using the Langevin equation. By analyzing
    the trajectory in the deformation space, we identify the critical area when the
    trajectory's destination is determined to be the fusion or the quasi-fission
    process. It is also clarified that the potential landscape around the critical
    area is crucial for estimating the fusion probability, and its dependence on
    the atomic number is presented.
  • Trajectory analysis for fusion path in superheavy-mass region, Y. Aritomo, M. Ohta, Nucl.Phys. A753 (2005) 152-173, Nucl.Phys. A753 (2005) 152-173, 753, 152 - 173, Feb. 15 2005
    Summary:We propose an effective method for the precise investigation of the
    fusion-fission mechanism in the superheavy-mass region, using the
    fluctuation-dissipation model. The trajectory calculation with friction is
    performed in the nuclear deformation space using the Langevin equation. In the
    reaction $^{48}$Ca+$^{244}$Pu, the trajectories are classified into the
    fusion-fission process, the quasi-fission process and the deep quasi-fission
    process. By analyzing the time evolution of each trajectory, the mechanism of
    each process is clearly revealed, i.e., it is explained why a trajectory takes
    a characteristic path in this model. We discuss, in particular, the condition
    under which the fusion path is followed, which is crucial in the discussion of
    the possibility of synthesizing superheavy elements.
  • Dynamical calculation for fusion-fission probability in superheavy mass region, where mass symmetric fission events originate, Yoshihiro Aritomo, Yoshihiro Aritomo, Masahisa Ohta, Nuclear Physics A, Nuclear Physics A, 744, 3 - 14, Nov. 15 2004
    Summary:We discuss dynamically the fusion-fission mechanism in the superheavy mass region. By analyzing the mass distribution of fission fragments, we distinguish between the fusion-fission process and the quasi-fission process. We investigate these two processes using the fluctuation-dissipation model. The three-dimensional Langevin equation is employed. We classify the dynamical process by analyzing the trajectory in the nuclear deformation space. In the superheavy mass region, we found that 90-99% of mass symmetric fission events come from the quasi-fission process, in which the system hardly reaches the spherical region. The fusion cross section is also estimated precisely. © 2004 Elsevier B.V. All rights reserved.
  • On evaporation residue cross sections producing nuclei with Z = 104-120, Masahisa Ohta, Yoshihiro Aritomo, Yoshihiro Aritomo, Kazuaki Hashizume, Acta Physica Hungarica, Series A: Heavy Ion Physics, Acta Physica Hungarica, Series A: Heavy Ion Physics, 19, 61 - 66, Jul. 22 2004
    Summary:A phenomenological method to predict the evaporation residue cross section in the superheavy mass region is presented. It makes us possible to understand what are the main contributors to the cross section and to perform a systematic analysis for understanding the fusion-fission mechanism by finding a deviation from the average property by means of this method.
  • Analysis of fusion-fission process with neutron evaporation in superheavy mass region, Yoshihiro Aritomo, Yoshihiro Aritomo, Masahisa Ohta, Acta Physica Hungarica, Series A: Heavy Ion Physics, Acta Physica Hungarica, Series A: Heavy Ion Physics, 19, 85 - 86, Jul. 22 2004
    Summary:The fusion-fission process for the synthesis of superheavy elements is discussed on the basis of the fluctuation-dissipation dynamics. We analyze the experimental data using a three-dimensional Langevin calculation. We take the neutron emission into account in the Langevin calculation and compare the results with experimental data. Also we discuss the evaporation residue cross section for superheavy elements.
  • Analysis of fusion-fission dynamics in superheavy mass region by pre-scission neutron multiplicities, Y. Aritomo, Y. Aritomo, M. Ohta, T. Materna, F. Hanappe, L. Stuttge, Nuclear Physics A, Nuclear Physics A, 738, 221 - 225, Jun. 28 2004
    Summary:We discuss thc fusion-fission process in superheavy mass region. By analyzing the mass distribution of fission fragments, we can distinguish between fusion-fission process and quasi-fission process. We investigate these two processes using the fluctuation-dissipation model. In the dynamical calculation, we employ the three-dimensional Langevin equation. We find 90 ∼ 99% of mass symmetric fission events come from the quasi-fission process in the superheavy mass region. In order to classify the fusion-fission process more precisely. we analyze the pre-scission neutron multiplicity. © 2004 Elsevier B.V. All rights reserved.
  • Tracking dissipation in capture reactions, T. Materna, V. Bouchat, V. Kinnard, F. Hanappe, O. Dorvaux, C. Schmitt, C. Schmitt, L. Stuttgé, K. Siwek-Wilczynska, Y. Aritomo, Y. Aritomo, A. Bogatchev, E. Prokhorova, M. Ohta, AIP Conference Proceedings, AIP Conference Proceedings, 704, 139 - 146, Apr. 12 2004
    Summary:© 2004 American Institute of Physics. Nuclear dissipation in capture reactions is investigated using backtracing. Combining the analysis procedure with dynamical models, the difficult and long-standing problem of competition and mixing of quasi-fission and fusion-fission is solved for the first time. At low excitation energy a new protocol able to handle low statistics data gives access to the prescission neutron multiplicity in two different systems48Ca +208Pb, Pu. The results are in agreement with a domination of fusion-fission in the case of256No and an equal mixing of quasi-fission and fusion-fission in the case of Z = 114. The nature of the relevant dissipation is determined as one-body dissipation.
  • On the excitation energy for maximum cold fusion reactions in superheavy mass region, A. Fukushima, T. Wada, M. Ohta, Y. Aritomo, Y. Aritomo, AIP Conference Proceedings, AIP Conference Proceedings, 704, 557 - 562, Apr. 12 2004
    Summary:© 2004 American Institute of Physics. We have analyzed cold fusion reactions, especially, (HI(Heavy-Ion), xn) reactions with208Pb target series. The ratio af/anused in the statistical model is determined by fitting experimental data of Γn/Γtotalfor Z=102 and the extrapolative use is made for Z>103. Theoretical predictions for excitation functions in208Pb(50Ti,51V,54Cr,55Mn,58Fe,59Co,65Cu,70Zn, xn) reactions are compared with experiments. We found that peak positions of (HI, xn) reactions except for the sub-barrier fusion enhancement effect stay almost constant when we increase the Z-number of compound nucleus from Z=104 to Z=110.
  • Dynamics of fusion-fission process in superheavy mass region, Y. Aritomo, Y. Aritomo, M. Ohta, T. Materna, F. Hanappe, L. Stuttge, AIP Conference Proceedings, AIP Conference Proceedings, 704, 147 - 156, Apr. 12 2004
    Summary:© 2004 American Institute of Physics. The fusion-fission process for the synthesis of superheavy elements is discussed on the basis of the fluctuation-dissipation model. Recently the experiments at Dubna on fission of superheavy nuclei were carried out, and the mass and total kinetic energy distributions of fission fragments were measured. By analyzing the mass distribution of fission fragments, we can distinguish between fusion-fission process and quasi-fission process. We employ three-dimensional Langevin equation. We find almost all of the mass symmetric fission events come from the quasi-fission process in the superheavy mass region. In order to classify the fusion-fission paths and compare with the experimental data directly, we analyze the pre-scission neutron emission in the correlation with fission fragments. The neutron multiplicity depends on the travelling time of the trajectory. It is useful to investigate the fusion-fission process.
  • Tracking dissipation in capture reactions, T. Materna, V. Bouchat, V. Kinnard, F. Hanappe, O. Dorvaux, C. Schmitt, C. Schmitt, L. Stuttgé, K. Siwek-Wilczyńska, Y. Aritomo, Y. Aritomo, A. Bogatchev, E. Prokhorova, M. Ohta, International Journal of Modern Physics E, International Journal of Modern Physics E, 13, 285 - 292, Feb. 01 2004
    Summary:Nuclear dissipation in capture reactions is investigated using backtracing. Combining the analysis procedure with dynamical models, the difficult and long-standing problem of competition and mixing of quasi-fission and fusion-fission is solved for the first time. At low excitation energy a new protocol able to handle low statistics data gives access to the prescission neutron multiplicity in two different systems 48Ca, + 208Pb, Pu. The results are in agreement with a domination of fusion-fission in the case of 256No and an equal mixing of quasi-fission and fusion-fission in the case of Z = 114. The nature of the relevant dissipation is determined as one-body dissipation.
  • Dynamical calculation for fusion-fission process in superheavy mass region, Y. Aritomo, Y. Aritomo, M. Ohta, T. Materna, F. Hanappe, L. Stuttgé, International Journal of Modern Physics E, International Journal of Modern Physics E, 13, 301 - 304, Feb. 01 2004
    Summary:The fusion-fission process for the synthesis of superheavy elements is discussed on the basis of fluctuation-dissipation model. We employ three-dimensional Langevin equation. We investigate the fusion-fission process by analyzing not only the mass distribution of fission fragments but also neutron multiplicity on fusion-fission process.
  • Tracking dissipation in capture reactions, T. Materna, F. Hanappe, Y. Aritomo, Y. Aritomo, L. Stuttgé, O. Dorvaux, C. Schmitt, C. Schmitt, M. Ohta, Progress of Theoretical Physics Supplement, Progress of Theoretical Physics Supplement, 154, 442 - 448, Jan. 01 2004
    Summary:Nuclear dissipation in capture reactions is investigated using backtracing. Combining the analysis procedure with dynamical models, the difficult and long-standing problem of competition and mixing of quasi-fission and fusion-fission is solved for the first time. At low excitation energy a new protocol able to handle low statistics data gives access to the prescission neutron multiplicity in two different systems 48Ca + 208Pb, Pu. The results are in agreement with a domination of fusion-fission in the case of 256No and an equal mixing of quasi-fission and fusion-fission in the case of Z = 114. The nature of the relevant dissipation is determined as one-body dissipation.
  • Problems of dynamical calculation for synthesis of superheavy elements, Yoshihiro Aritomo, Yoshihiro Aritomo, Masahisa Ohta, Thomas Materna, Francis Hanappe, Louise Stuttgé, Progress of Theoretical Physics Supplement, Progress of Theoretical Physics Supplement, 154, 449 - 456, Jan. 01 2004
    Summary:We discuss the fusion-fission process in super heavy mass region. In dynamical calculation, we list up the problems and discuss the sensitivity of the parameters. Using the fluctuation-dissipation model we investigate the fusion-fission process and estimate the fusion cross section precisely.
  • Tracking dissipation in capture reactions, T. Materna, C. Schmitt, Y. Aritomo, Y. Aritomo, J. Bartel, B. Benoit, A. A. Bogatchev, E. De Goès Brennand, O. Dorvaux, G. Giardina, F. Hanappe, M. G. Itkis, I. M. Itkis, J. Kliman, G. N. Kniajeva, N. A. Kondratiev, E. M. Kozulin, L. Krupa, Yu Ts Oganessian, I. V. Pokrovsky, E. V. Prokhorova, N. Rowley, K. Siwek-Wilczynska, L. Stuttgé, Physics of Atomic Nuclei, Physics of Atomic Nuclei, 66, 1168 - 1172, Jun. 01 2003
    Summary:Nuclear dissipation in capture reactions is investigated using backtracing, a new analysis protocol. Combining analysis procedure with dynamical models, the difficult and long-standing problem of competition and mixing between quasifission and fusion-fission is solved for the first time. The nature of the relevant dissipation is determined as one-body dissipation. At low excitation energy where shell effects are strongly effective, the shape of the mass distribution could be a powerful check of the nature and the magnitude of the dissipation. © 2003 MAIK "Nauka/Interperiodica".
  • Analysis of fusion-fission process with neutron evaporation in superheavy mass region, Y. Aritomo, Y. Aritomo, M. Ohta, Physics of Atomic Nuclei, Physics of Atomic Nuclei, 66, 1105 - 1113, Jun. 01 2003
    Summary:The fusion-fission process for the synthesis of superheavy elements is discussed on the basis of fluctuation-dissipation dynamics. Recently, experiments at Dubna on fission of superheavy nuclei were carried out, and the mass and total kinetic energy distributions of fission fragments were measured. The fusion-fission cross section was derived from the experiments. We analyze the data using a three-dimensional Langevin calculation. We present a clear understanding of the competition between the fusion and the quasifission. We emphasize that a one- or two-dimensional model of Langevin calculation is not sufficient to estimate the fusion cross section in the superheavy mass region. Also, experiments on the emission of neutrons in correlation with fission fragments were conducted. It is useful to investigate the fusion-fission dynamics. We take into account the neutron emission with a Langevin calculation and compare it with experimental data. Finally, we discuss the evaporation residue cross section for superheavy elements. © 2003 MAIK "Nauka/Interperiodica".
  • An idea for predicting the evaporation residue cross section in superheavy mass region, M. Ohta, Y. Aritomo, Y. Aritomo, Physics of Atomic Nuclei, Physics of Atomic Nuclei, 66, 1026 - 1032, Jun. 01 2003
    Summary:A trial to clarify the main contributors to the evaporation residue cross section in the superheavy mass region is presented. The precise analysis of these factors enables us to understand more clearly the trend of experimental data decreasing exponentially when the atomic number of the residue nucleus increases. It is found that almost all of the experimental data producing nuclei with Z = 104 to 114 are fitted with a common parameter set within a reasonable allowance, i.e., ±0.7 order. In this sense, this model has a reliable predictability for the synthesis of new elements. © 2003 MAIK "Nauka/Interperiodica".
  • Fusion-fission process of superheavy elements with fluctuation-dissipation model, Yoshihiro Aritomo, Yoshihiro Aritomo, Progress of Theoretical Physics, Progress of Theoretical Physics, 503 - 507, Dec. 01 2002
    Summary:The fusion-fission process for the synthesis of superheavy elements is discussed based on fluctuation-dissipation dynamics. Recent data from Dubna on a fusion-fission cross section derived from fission experiments in the reactions 48Ca+208Pb, 48Ca+238U, 48Ca+244Pu and 48Ca+248Cm are analyzed using a three-dimensional Langevin calculation. We found that the quasi-fission process contributes to the yield of mass symmetric fission fragments. In superheavy mass region, the dynamical deformation of fragments is very important. The one- or two-dimensional calculation is not enough to describe the dynamics of fusion-fission process.
  • Synthesis of superheavy nuclei: How accurately can we describe it and calculate the cross sections?, V. I. Zagrebaev, Y. Aritomo, M. G. Itkis, Yu Ts Oganessian, M. Ohta, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 65, 146071 - 1460714, Jan. 01 2002
    Summary:A thorough analysis of all stages of heavy ion fusion reaction leading to the formation of a heavy evaporation residue has been performed. The main goal of the analysis was to gain better understanding of the whole process and to find out what factors and quantities, in particular, bring major uncertainty into the calculated cross sections, how reliable the calculation of the cross sections of superheavy element formation may be and what additional theoretical and experimental studies should be made in this field.
  • Systematics on superheavy elements formation, Masahisa Ohta, Yoshihiro Aritomo, Yoshihiro Aritomo, Journal of Nuclear Science and Technology, Journal of Nuclear Science and Technology, 39, 586 - 591, Jan. 01 2002
    Summary:Based on numerical results by three dimensional Langevin calculation, a functional form of formation probability is derived. Combining with survival probability estimated by the statistical model, we reproduced a general trend of experimental data and understandings. Through our systematic analysis, we propose the Synthesis Index (SI) which is useful for searching which entrance channel is preferable to produce new elements. © 2014 Atomic Energy Society of Japan.
  • Favorable combination for the synthesis of superheavy elements, M. Ohta, K. Okazaki, T. Wada, Y. Aritomo, Y. Abe, Acta Physica Hungarica New Series Heavy Ion Physics, Acta Physica Hungarica New Series Heavy Ion Physics, 10, 253 - 264, Dec. 01 1999
    Summary:Suitable target-projectile combinations for synthesis of the superheavy element Z = 114 are discussed for the case of the two isotopes A = 298 and A = 290, which are the neutron-rich isotope and the normal one, respectively. In our framework of estimating the evaporation residue cross section by using the Langevin or the diffusion equation, it is shown that the fusion reaction leading to a neutron-rich nucleus has an advantage around the entrance channel mass asymmetry parameter α = 0.65. On the contrary, lower mass asymmetry is favorable in the case of the normal nucleus, although the absolute value of the cross section is depressed drastically. We also present quantitatively the importance of neutron richness in the synthesis of superheavy elements.
  • Multi-dimensional fluctuation-dissipation dynamics of the synthesis of superheavy elements, T. Wada, Y. Aritomo, Y. Aritomo, T. Tokuda, K. Okazaki, M. Ohta, Y. Abe, Nuclear Physics A, Nuclear Physics A, 654, Jul. 26 1999
    Summary:We study the dynamical process of synthesizing superheavy elements on the basis of the fluctuation-dissipative dynamics with a multi-dimensional diffusion model. A multi-dimensional Langevin equation is used from the contact of two nuclei. After the dissipation of relative kinetic energy, a two-dimensional Smoluchowski equation is adopted taking into account the temperature dependent shell correction energy. The fusion probability is large for high incident energies. For low incident energies, owing to the restoration of the shell correction energy, the survival provability against fission is large. The competition between the two factors results in the optimum energy at 20-30 MeV. A three-dimensional model is used for the treatment of mass-asymmetric incident channels.
  • Fluctuation-dissipation model for synthesis of superheavy elements, Y. Aritomo, T. Wada, M. Ohta, Y. Abe, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 59, 796 - 809, Feb. 01 1999
    Summary:Fusion-fission dynamics in superheavy elements is investigated by an approximate fluctuation-dissipation model, i.e., a diffusion model in the deformation space, assuming that the kinetic energy of the incident ion dissipates immediately after the contact. The probability accumulated inside the fission barrier is calculated by the one-dimensional Smoluchowski equation taking account of the temperature dependence of the shell correction energy. A new mechanism for an optimum condition is found as a compromise of two conflicting requirements: higher incident energy for larger fusion probability and lower excitation energy of compound nuclei for larger survival probability. Enhancements of the residue cross sections at the optimum condition are obtained for the cases in which the cooling is quick to restore the shell correction energy, combined with slow fissioning motion due to the strong friction. With symmetric combinations of incident ions, the (HI, 3-4n) channels show the enhancement.
  • A new mechanism for synthesis of super-heavy elements, Y. Abe, Y. Aritomo, T. Wada, M. Ohta, Journal of Physics G: Nuclear and Particle Physics, Journal of Physics G: Nuclear and Particle Physics, 23, 1275 - 1284, Oct. 01 1997
    Summary:A dynamical theory is proposed for nuclear reactions leading to residues of superheavy elements. Fusion and fission processes are treated consistently by a diffusion equation which describes a time-dependent probability distribution in the collective coordinate or deformation space. The potential energy in the equation is time-dependent, because cooling due to particle evaporation gradually restores the shell correction energy which gives rise to a potential pocket essential for the stabilization of the superheavy elements around Z = 114 and N = 184. It is shown that there is an optimum initial excitation energy or incident energy of reactions as the result of a compromise between two conflicting requirements; higher energies which favour larger fusion probabilities and lower energies which favour larger residue probabilities or a quicker restoration of the shell-correction energy. A promising experimental direction is suggested.
  • Dynamics of the superheavy element synthesis with a diffusion model, T. Wada, Y. Aritomo, T. Tokuda, M. Ohta, Y. Abe, Nuclear Physics A, Nuclear Physics A, 616, 446 - 453, Apr. 14 1997
    Summary:A diffusion model is proposed for the dynamical treatment of the synthesis of superheavy elements. Fusion-fission process is analyzed by one-dirnensional Smoluchowski equation with liquid drop model potential of no pocket and the temperature dependent shell correction energy which generates the pocket around the spherical shape. Competition between fission and neutron evaporation is taken into account in terms of the continuous cooling by neutron evaporation. The evaporation residue cross sections of superheavy elements have been shown to have an optimum value at a certain temperature, due to the balance between the diffusibility for fusion at high temperature and the restoration of the shell correction energy against fission at low temperature. The isotope dependence of the evaporation residue cross section is found to be very strong. Neutron rich compound system with small neutron separation energy is favorable for larger cross section because of the quick restoration of the shell correction energy.
  • Diffusion mechanism for synthesis of superheavy elements, Y. Aritomo, T. Wada, M. Ohta, Y. Abe, Physical Review C - Nuclear Physics, Physical Review C - Nuclear Physics, 55, Mar. 01 1997
    Summary:The fusion-fission process in heavy systems is analyzed by the Smoluchowski equation with the finite-range droplet model potential of no pocket and the temperature-dependent shell correction energy which generates the pocket around the spherical shape. The evaporation residue cross sections of superheavy elements have been shown to have an optimum value at a certain initial temperature, due to the balance between the diffusibility for fusion at high temperature and the restoration of the shell correction energy against fission at low temperature.

Books etc

  • The Papanicolaou Society of Cytopathology System for Reporting Pancreaticobiliary Cytology: Definitions, Criteria and Explanatory Notes, Martha Bishop Pitman, Lester Layfield, Springer,   2015 05 31 , 3319165887
  • Autophagy and Cancer (Current Cancer Research), Hong-Gang Wang, Springer,   2015 02 08 , 1489991778
  • Exotic Nuclei: EXON-2012, Yu E Penionzhkevich, Yu G Sobolev, Yu E Penionzhkevich, Yu G Sobole, World Scientific Publishing Company,   2013 06 25 , 9814508853
  • Nuclear Structure in China 2012: Proceedings of the 14th National Conference on Nuclear Structure in China, Jie Meng, Jie Meng, Cai-Wan Shen, En-Guang Zhao, Shan-Gui Zhou, World Scientific Publishing Company,   2012 11 27 , 9814447471
  • Theory of Nuclear Fission: A Textbook (Lecture Notes in Physics), Hans J. Krappe, Krzysztof Pomorski, Springer,   2012 02 06 , 364223514X
  • Clusters in Nuclei: Volume 1 (Lecture Notes in Physics), Christian Beck, Springer,   2010 09 18 , 9783642138980
  • Dynamical Aspects of Nuclear Fission: Proceedings of the 6th International Conference, Smolenice Castle, Slovak Republic, 2-6 Ocotber 2006, J. Kliman, M. G. Itkis, S. Gmuca, World Scientific Pub Co Inc,   2009 11 13 , 9812837523
  • The Euroschool Lectures on Physics with Exotic Beams, Vol. III (Lecture Notes in Physics), J.S. Al-Khalili, Ernst Roeckl, Springer,   2008 12 16 , 3540858385
  • International Symposium On Exotic Nuclei: Peterhof, Russia, July 5-12, 2004, International, Symposium on, Exotic Nuclei, Yu E. Penionzhkevich, E. A. Cherepanov, World Scientific Pub Co Inc,   2005 12 30 , 981256392X
  • Structure and Dynamics of Elementary Matter (Nato Science Series II:), Walter Greiner, Mikhail G. Itkis, Joachim Reinhardt, Mehmet Cem Güçlü, Springer,   2004 11 03 , 1402024460

Conference Activities & Talks

  • Analysis of Evaporation Residue Cross Section in Synthesizing Superheavy Element Region, ANUAR Nur Liyana Mohd, ARITOMO Yoshihiro, TANAKA Shoya, YANAGI Baku, 日本物理学会講演概要集(CD-ROM),   2018 03 23
  • Estimation for possibility of synthesizing superheavy element using Dynamical model, ANUAR Nur Liyana Mohd, TANAKA Shoya, YANAGI Baku, MIYAMOTO Yuuya, SHALADDIN Ahma, Kushairi Mohd, ARITOMO Yoshihiro, 日本物理学会講演概要集(CD-ROM),   2017 09 25
  • 21aAC-8 Effect on particle evaporation during fusion-fission process for synthesis of superheavy elements, Aritomo Y, Hagino K, Nishio K, Ohta M, Meeting Abstracts of the Physical Society of Japan,   2016
  • 低エネルギー核分裂過程の動的機構の解明, ARITOMO YOSHIHIRO, HOSODA DAISUKE, CHIBA SATOSHI, 日本原子力学会春の年会予稿集(CD-ROM),   2015 03 05
  • 27aSP-7 Effect on particle evaporation during fusion-fission process for synthesis of superheavy elements, Aritomo Y, Hagino K, Nishio K, Ohta M, Meeting Abstracts of the Physical Society of Japan,   2015
  • 21pCB-7 Fission properties of trans-Bk nuclei with Langevin approach, Aritomo Y, Hosoda D, Chiba S, Nishio K, Meeting Abstracts of the Physical Society of Japan,   2015
  • 25pSF-4 Experimental research on fusion-fission and multi-nucleon transfer reactions at JAEA, Hirose K, Nishio K, Nishinaka I, Mitsuoka S, Makii H, Ikezoe H, Orlandi R, Leguillon R, Smallcombe J, Tsukada K, Asai M, Nagame Y, Andreyev A, Hofmann S, Ackermann D, Hessberger F. P, Heinz S, Khuyagbaatar J, Kindler B, Comas V. F, Heredia J. A, Kojouharov I, Lommel B, Mann R, Dullmann Ch. E, Yakushev A, Popeko A. G, Yeremin A, Kuusiniemi P, Antalic S, Saro S, Chiba S, Ohtsuki, Aritomo Y, Hagino, Yan S, Tatsuzawa R, Takaki N, Tamura N, Goto S, Watanabe Y, Meeting Abstracts of the Physical Society of Japan,   2015
  • 25pSF-5 Shell effect in fission process with Langevin approach, Aritomo Y, Meeting Abstracts of the Physical Society of Japan,   2015
  • 4次元ランジュバン方程式を用いた核分裂モードの研究, ARITOMO YOSHIHIRO, HOSODA DAISUKE, CHIBA SATOSHI, 日本原子力学会秋の大会予稿集(CD-ROM),   2014 08 22
  • 動的模型による核分裂機構の系統的研究, HOSODA DAISUKE, ARITOMO YOSHIHIRO, CHIBA SATOSHI, 日本原子力学会秋の大会予稿集(CD-ROM),   2014 08 22
  • 核分裂片質量数及びTKE分布に対する対相関及びネック半径の影響, HOSODA DAISUKE, ARITOMO YOSHIHIRO, CHIBA SATOSHI, 日本原子力学会春の年会予稿集(CD-ROM),   2014 03 10
  • 核分裂における断裂点付近の形状と分裂モードの解析, ARITOMO YOSHIHIRO, HOSODA DAISUKE, CHIBA SATOSHI, HANABUSA KEN'ETSU, 日本原子力学会春の年会予稿集(CD-ROM),   2014 03 10
  • 30aTB-12 Dynamics of fission process with dynamical approach, Aritomo Yoshihiro, Hosoda Daisuke, Chiba Satoshi, Iwamoto Akira, Meeting abstracts of the Physical Society of Japan,   2014 03 05
  • 動力学模型を用いた核分裂過程のダイナミクス, ARITOMO YOSHIHIRO, HOSODA DAISUKE, CHIBA SATOSHI, IWAMOTO AKIRA, 日本物理学会講演概要集,   2014 03 05
  • Fission process of low excited nuclei with dynamical approach, Aritomo Yoshihiro, Chiba Satoshi, Meeting abstracts of the Physical Society of Japan,   2013 08 26
  • 動力学模型による低励起核分裂の計算, ARITOMO YOSHIHIRO, CHIBA SATOSHI, 日本物理学会講演概要集,   2013 08 26
  • 高燃焼度原子炉動特性評価のための遅発中性子収率高精度化に関する研究開発(3)ランジュバン方程式による核分裂片独立収率の計算手法の開発, ARITOMO YOSHIHIRO, CHIBA SATOSHI, NISHIO KATSUHISA, HANABUSA KEN'ETSU, 日本原子力学会秋の大会予稿集(CD-ROM),   2013 08 20
  • JAEAにおける代理反応研究の成果(1)全体計画と理論研究, CHIBA SATOSHI, ARITOMO YOSHIHIRO, KOURA HIROYUKI, IWAMOTO OSAMU, UTSUNO YUTAKA, HASHIMOTO SHINTARO, 日本原子力学会秋の大会予稿集(CD-ROM),   2012 09 03
  • 20aBH-8 Analysis of surrogate reaction using unified model, Aritomo Y, Chiba S, Hashimoto S, Meeting abstracts of the Physical Society of Japan,   2010 03 01
  • 23aSC-10 Initial conditions for the analysis of heavy-ion fusion reactions with the multi-dimensional Langevin equations, Fukushima A, Wada T, Ohta M, Nasirov A, Aritomo Y, Meeting abstracts of the Physical Society of Japan,   2006 08 18
  • 23aSC-8 Fission fragment mass distributions in the r-process region II, Samyn M, Goriely S, Meeting abstracts of the Physical Society of Japan,   2006 08 18
  • 23aSC-9 Fission fragment mass distributions in the r-process region, Tatsuta S, Yamamoto K, Wada T, Ohta M, Sumiyoshi K, Otsuki K, Kajino T, Koura H, Chiba S, Meeting abstracts of the Physical Society of Japan,   2006 08 18
  • 29pWF-2 An improved dynamical approach to fusion processes with the multi-dimensional Langevin equations, Fukushima A, Wada T, Ohta M, Nasirov A, Aritomo Y, Meeting abstracts of the Physical Society of Japan,   2006 03 04
  • Prediction for the maximum cross section of superheavy nuclei II, OHTA M, ARITOMO Y, Meeting abstracts of the Physical Society of Japan,   2003 03 06
  • Systematics of cross sections for synthesizing superheavy nudei and the status of preparation for synthesizing an unknown 113th element at RIKEN, Morita K, Ohta M, Aritomo Y, Meeting abstracts of the Physical Society of Japan,   2002 08 13
  • Prediction for the maximum cross section of superheavy nuclei II, OHTA M, ARITOMO Y, Meeting abstracts of the Physical Society of Japan,   2002 08 13
  • Analysis of fusion-fission process with neutron evaporation in superheavy mass region, ARITOMO Y, OHTA M, Meeting abstracts of the Physical Society of Japan,   2002 08 13
  • Systematic trend on the synthesis of superheavy elements(I), Ohta M, Aritomo Y, Wada T, Ichikawa T, Meeting abstracts of the Physical Society of Japan,   2001 03 09
  • 29p-YF-12 The Estimation for the Evaporation Residue Cross Section of Fusion Reactions <48>^Ca^+<238>^U etc.with Dissipation-Fluctuation Dynamics, Okazaki K, Tokuda T, Aritomo Y, Wada T, Ohta M, Abe Y, Meeting abstracts of the Physical Society of Japan,   1999 03 15
  • The Evaporation Residue Cross Section in Super Heavy Mass Region with Mass Asymmetry, OKAZAKI K, TOKUDA T, ARITOMO Y, WADA T, OHTA M, ABE Y, Meeting abstracts of the Physical Society of Japan,   1998 09 05
  • On the Synthesis of Super Heavy Element by Asymmetry Fusion Reaction, OKAZAKI K, TOKUDA T, ARITOMO Y, WADA T, OHTA M, ABE Y, Meeting abstracts of the Physical Society of Japan,   1998 03 10
  • 23p-A-3 Estimation of Evaporation Residue Cross Section of Superheavy Elements by multi-dimensional Diffusion Model, Aritomo Y, Okazaki K, Wada T, Ohta M, Abe Y, Meeting abstracts of the Physical Society of Japan,   1997 09 02
  • 23p-A-1 Relaxation of Collective Degrees of Freedom in Heavy Nuclear Fusion Reaction, Okazaki K, Tokuda T, Aritomo Y, Wada T, Ohta M, Abe Y, Meeting abstracts of the Physical Society of Japan,   1997 09 02
  • 28p-YM-4 Estimation of Evaporation Residue Cross Section of Superheavy Elements by 2-dimensional Diffusion Model, Aritomo Y, Wada T, Ohta M, Abe Y, Meeting abstracts of the Physical Society of Japan,   1997 03 17
  • 6a-F-4 Systematics of Evaporation Residue Cross Section of Superheavy Elements by Diffusion Model, Aritomo Y, Wada T, Ohta M, Abe Y, Abstracts of the meeting of the Physical Society of Japan. Sectional meeting,   1996 09 13
  • 6a-F-3 Cooling Property of Excited Nuclei in Superheavy Mass Region, Tokuda T, Aritomo Y, Wada T, Ohta M, Abstracts of the meeting of the Physical Society of Japan. Sectional meeting,   1996 09 13
  • 30p-SB-10 Estimation of Evaporation Residue Cross Section of Superheavy Elements by Diffusion Model, Aritomo Y, Wada T, Ohta M, Abe Y, Abstracts of the meeting of the Physical Society of Japan. Sectional meeting,   1995 09 12

Misc

  • Isotopic distribution of 235U + n .RAR. 236U at low E* using 4D-Langevin calculation, ISHIZUKA Chikako, CHIBA Satoshi, KARPOV Alexander V, ARITOMO Yoshihiro, 日本原子力研究開発機構JAEA-Conf(Web), 2016-004, 99‐103 (WEB ONLY),   2016 09 , http://jglobal.jst.go.jp/public/201602271718310562
  • Fusion of Massive Systems and Superheavy Elements, Hagino Kouichi, Aritomo Yoshihiro, 日本物理學會誌, 68, 10, 654, 661,   2013 10 05 , http://ci.nii.ac.jp/naid/110009674452
    Summary:On August 12, 2012, the anticipated event for the element 113 (with the atomic number 113 and the mass number 278) was detected in the fusion reaction between ^<70>Zn and ^<209>Bi by the experimental group led by Dr. Kosuke Morita at RIKEN. The potential energy between two colliding nuclei consists of a short range nuclear attraction and the long range Coulomb repulsion, and the potential barrier, which is referred to as the Coulomb barrier, appears due to the strong cancellation between the two interactions. For relatively light systems, such as ^<16>O + ^<209>Bi, fusion takes place once the Coulomb barrier is overcome. In contrast, for massive systems, such as ^<70>Zn + ^<209>Bi used in the experiment by Morita, et al., the quasi-fission process, in which the two nuclei reseparate after the Coulomb barrier is overcome, becomes increasingly dominant, and the fusion cross sections are hindered accordingly. Moreover, even if the fusion is succeeded, the compound nucleus quickly decays by the (ordinary) fission. In this article, we first discuss how it is rare to synthesize a new element by heavy-ion fusion reactions and discuss a significance of the experimental result of Dr. Morita, et al. We also discuss a comparison between the so called hot fusion and cold fusion reactions, a transition of fusion dynamics from light systems to heavy systems, and the role of nuclear structure such as nuclear deformation on fusion of massive systems.
  • New fission mechanism peculiar to proton-rich nuclei, ANDREYEV Andrei, NISHIO Katsuhisa, DERKX Xavier, LANE Joseph, LIBERATI Valentina, SANDHU Kalvinder, CHIBA Satoshi, MITSUOKA Shin‐ichi, NISHINAKA Ichiro, MAKII Hiroyuki, WAKABAYASHI Yasuo, ARITOMO Yoshihiro, OTA Shuya, NAGAYAMA Tatsuro, GHYS Lars, OHTSUKI Tsutomu, 日本原子力研究開発機構JAEA-Review(Web), 2012-036, 9-13 (WEB ONLY),   2012 10 , http://jglobal.jst.go.jp/public/201302242961026405
  • Possibility of synthesizing doubly closed superheavy nucleus, ARITOMO Yoshihiro, 素粒子論研究, 115, 3, C50,   2007 08 20 , 10.24532/soken.115.3_C50, http://jglobal.jst.go.jp/public/200902268061470055
  • Dubna, The Center of Investigation for Superheavy Elements(La Toccata), Aritomo Yoshihiro, 日本物理學會誌, 56, 9, 695, 697,   2001 09 05 , http://ci.nii.ac.jp/naid/110008006958

Awards & Honors

  •   2003 01 , The Scientific Council of the Joint Institute for Nuclear Research Awarded., The second prize of the Joint Institute for Nuclear Research.

Research Grants & Projects

  • Russia and Germany, No. 04-02-04008