9 research outputs found

    Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Sections for 6Li + 208Pb System at Near-Coulomb-Barrier Energies by using Folding Potential

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    Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous Ōá2\chi^{2} analyses are performed for elastic scattering and fusion cross section data for the 6^{6}Li+208^{208}Pb system at near-Coulomb-barrier energies. A folding potential is used as the bare potential. It is found that the real part of the resultant DR part of the polarization potential is repulsive, which is consistent with the results from the Continuum Discretized Coupled Channel (CDCC) calculations and the normalization factors needed for the folding potentials. Further, it is found that both DR and fusion parts of the polarization potential satisfy separately the dispersion relation.Comment: 6 figure

    Extended Optical Model Analyses of Elastic Scattering, Direct Reaction, and Fusion Cross Sections for the 9Be + 208Pb System at Near-Coulomb-Barrier Energies

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    Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous Ōá2\chi^{2} analyses are performed for elastic scattering, DR, and fusion cross section data for the 9^{9}Be+208^{208}Pb system at near-Coulomb-barrier energies. Similar Ōá2\chi^{2} analyses are also performed by only taking into account the elastic scattering and fusion data as was previously done by the present authors, and the results are compared with those of the full analysis including the DR cross section data as well. We find that the analyses using only elastic scattering and fusion data can produce very consistent and reliable predictions of cross sections particularly when the DR cross section data are not complete. Discussions are also given on the results obtained from similar analyses made earlier for the 9^{9}Be+209^{209}Bi system.Comment: 5 figure

    Sensitivity of nucleon-nucleus scattering to the off-shell behavior of on-shell equivalent NN potentials

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    The sensitivity of nucleon-nucleus elastic scattering to the off-shell behavior of realistic nucleon-nucleon interactions is investigated when on-shell equivalent nucleon-nucleon potentials are used. The study is based on applications of the full-folding optical model potential for an explicit treatment of the off-shell behavior of the nucleon-nucleon effective interaction. Applications were made at beam energies between 40 and 500 MeV for proton scattering from 40Ca and 208Pb. We use the momentum-dependent Paris potential and its local on-shell equivalent as obtained with the Gelfand-Levitan and Marchenko inversion formalism for the two nucleon Schroedinger equation. Full-folding calculations for nucleon-nucleus scattering show small fluctuations in the corresponding observables. This implies that off-shell features of the NN interaction cannot be unambiguously identified with these processes. Inversion potentials were also constructed directly from NN phase-shift data (SM94) in the 0-1.3 GeV energy range. Their use in proton-nucleus scattering above 200 MeV provide a superior description of the observables relative to those obtained from current realistic NN potentials. Limitations and scope of our findings are presented and discussed.Comment: 17 pages tightened REVTeX, 8 .ps figures, submitted to Phys. Rev.

    An isospin dependent global nucleon-nucleus optical model at intermediate energies

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    A global nucleon-nucleus optical potential for elastic scattering has been produced which replicates experimental data to high accuracy and compares well with other recently formulated potentials. The calculation that has been developed describes proton and neutron scattering from target nuclei ranging from carbon to nickel and is applicable for projectile energies from 30 to 160 MeV. With these ranges it is suitable for calculations associated with experiments performed by exotic beam accelerators. The potential is also isospin dependent and has both real and imaginary isovector asymmetry terms to better describe the dynamics of chains of isotopes and mirror nuclei. An analysis of the validity and strength of the asymmetry term is included with connections established to other optical potentials and charge-exchange reaction data. An on-line observable calculator is available for this optical potential.Comment: 31 pages, 21 figures, 4 tables; Accepted to Phys. Rev. C. This version includes corrections to Eq. 1 and Table 1. Erratum sent to Phys. Rev.

    Technical progress report : advanced marine technology 1 February 1973 - 31 July 1973

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    This report covers a period which finds several of the projects nearing completion. It is expected that the next semi-annual report should contain final technical reports on Submerged navigation, Hydraulic Impact Hammer, Deep Sea Rock Drill and the Shelf Contained Ancillary Modular Package (SCAMP). It is possible that extensive testing and use of SCAMP will not take place until next year. The responsibility for these worthwhile equipments then shifts to the users, who in most cases has been intimately involved in the development. The Submerged Navigation system continues to attract much attention both within and without the Institution. Delays in the fitting and testing of ALVIN in the Titanium hull configuration has slowed the field work with ARPA developed equipment bu the next six months should contain considerable work.Prepared for the Office of naval Research under Contract N00014-71-C-0284; NR 293-00
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