Systematics and uncertainties of Hamiltonian parameters of soft-rotator model for actinides and their implications for nuclear data calculations

Chiba, Satoshi; Koura, Hiroyuki; Maruyama, Toshiki; Kunieda, Satoshi; Soukhovitskij, E. Sh.*

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.305 - 308, 2008/06

https://doi.org/10.1051/ndata:07728

A coupled-channel (CC) method based on the soft-rotator model (SRM) wave functions, SRM-CC, has been recognized as a powerful tool to calculate, estimate and evaluate the nucleon-induced cross sections. It is because that this method can take account of the information from the nuclear structure and reaction studies simultaneously. For example, the coupling strengths required in the coupled-channel calculation is determined from analyses of low-lying collective level structure of target nuclei. However, nobody has looked into so far how the uncertainties of the SRM parameters affects the calculated cross section data. In this work, collective level structure of 19 even-even actinide nuclei are analyzed in terms of the soft-rotator model (SRM). Hamiltonian parameters of SRM to describe the low-lying level scheme and their uncertainties are obtained. Systematic trends are found for major Hamiltonian parameters as a function of ground-state quadrupole deformation which are important to estimate low-lying level structure of other e-e nuclei for which level structure is unknown or only partly known. Then, those parameters and their uncertainties are used to calculate neutron cross sections and their covariance of actinides in terms of SRM-CC. Furthermore, effects of side-band coupling is investigated. Especially, effects of coupling are noticeable for low-energy observables, e.g., strength functions. Such saturated calculations are not possible in RRM (rigid rotor model)-CC approach, making SRM-CC an effective method for investigations of reaction mechanisms and nuclear data evaluation.

Angular distributions of protons scattered by Ar nuclei with excitation of the 2 (1.46 MeV) and 3 (3.68 MeV) collective levels for incident energies of 25.1, 32.5, and 40.7 MeV

Okumusoglu, N. T.*; Gorur, F. K.*; Birchall, J.*; Soukhovitskij, E. Sh.*; Capote, R.*; Quesada, J. M.*; Chiba, Satoshi

Physical Review C, 75(3), p.034616_1 - 034616_10, 2007/03

https://doi.org/10.1103/PhysRevC.75.034616

Elastic and inelastic scattering of unpolarized and polarized protons by Ar nuclei for incident energies between 20 and 50 MeV has been studied by reanalyzing experimental scattering spectra for the 2 (1.46 MeV) and 3 (3.68 MeV) levels in the angular range 30 - 160 for incident protons of energies of 25.1, 32.5, and 40.7 MeV. An isospin dependent soft-rotator coupled channels optical model with the potential containing a dispersive term with a nonlocal contribution is used to analyze the data.

Dispersive coupled-channel analysis of nucleon scattering from Th up to 200 MeV

Soukhovitskij, E. Sh.*; Capote, R.*; Quesada, J. M.*; Chiba, Satoshi

Physical Review C, 72(2), p.024604_1 - 024604_12, 2005/08

https://doi.org/10.1103/PhysRevC.72.024604

Lane consistent coupled channels optical model potential (OMP) containing a dispersive term including nonlocal contribution is used to simultaneously fit the available experimental database (including strength functions and scattering radius) for neutron and proton scattering on strongly deformed Th nucleus. The energy range 0.001-200 MeV is covered. A dispersive coupled-channel optical model (DCCOM) potential with parameters that show a smooth energy dependence and energy independent geometry are determined from fits to the entire data set. Dispersive contribution is shown to be the dominant Coulomb correction to the proton real potential below the Coulomb barrier. Inclusion of nonlocality effects in the absorptive volume potential and its corresponding dispersive contribution to the real potential is needed to achieve an excellent agreement above 100 MeV.

Physics and numerical methods of OPTMAN; A Coupled-channels method based on soft-rotator model for a description of collective nuclear structure and excitations

Soukhovitskij, E. Sh.*; Morogovskij, G. B.*; Chiba, Satoshi; Iwamoto, Osamu; Fukahori, Tokio

JAERI-Data/Code 2004-002, 32 Pages, 2004/03

JAERI-Data-Code-2004-002.pdf:1.43MB

This report gives a detailed description of the theory and computational algorithms of modernized coupled-channels optical model code OPTMAN based on the soft-rotator model for the collective nuclear structure and excitations. This work was performed under the Project Agreement B-521 with the International Science and Technology Center (Moscow), financing party of which is Japan. As a result of this work, the computational method of OPTMAN was totally updated, and an user-friendly interface was attached.

Evaluation of FP nuclear data for JENDL-4, 2; Optical model analysis

Kunieda, Satoshi; Chiba, Satoshi; Shibata, Keiichi; Ichihara, Akira; Soukhovitskij, E. Sh.*

no journal, , 

no abstracts in English

Collective level structure and neutron cross sections of actinides by SRM-CC

Chiba, Satoshi; Koura, Hiroyuki; Kunieda, Satoshi; Soukhovitskij, E. Sh.*

no journal, , 

no abstracts in English