TITLE

R-matrix studies of astrophysical capture reactions

AUTHOR(S)
Johnson, A. S.; Hale, G. M.
PUB. DATE
July 2000
SOURCE
AIP Conference Proceedings;2000, Vol. 529 Issue 1, p466
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
We report the recent results of R-matrix analyses of light systems directed at obtaining capture cross sections for reactions of interest in nuclear astrophysics. The two examples discussed are [sup 1]H(n,γ)[sup 2]H and [sup 12]C(α,γ)[sup 16]O. The first reaction is important in Big-Bang nucleosynthesis at energies well up into hundreds of keV. The second reaction is crucial for determining the relative abundances of carbon and oxygen at the end of the helium-burning phase, but at energies below the range of current measurements. In both cases, the direct measurements are rather sparse and sometimes difficult to interpret because of level-structure uncertainties. However, the analyses we will describe make use of auxiliary data to determine the cross sections over wide ranges of energies, including those of astrophysical interest. © 2000 American Institute of Physics.
ACCESSION #
6029978

 

Related Articles

  • The application of the Wigner R-matrix theory to molecular collisions. Bocchetta, C. J.; Gerratt, J. // Journal of Chemical Physics;2/1/1985, Vol. 82 Issue 3, p1351 

    The Wigner–Eisenbud R-matrix theory is applied to molecular collisions. Previous attempts required a Buttle correction to accelerate slow convergence. The present theory makes use of radial basis functions which satisfy arbitrary conditions at the R-matrix boundary. At the same time...

  • Resonance Analysis in the Region of Unresolved Resonances. Lukyanov, A. A.; Koyumdjieva, N. T.; Janeva, N. B.; Volev, K. N.; Schillebeeckx, P. // AIP Conference Proceedings;2005, Vol. 769 Issue 1, p410 

    The independent analysis of new experimental data for 232Th cross sections in the unresolved region performed on the basis of the existing scheme and method of evaluation confirm the previously obtained average resonance parameters. The method of statistical modeling of the resonant...

  • SAMQUA — Quantum Numbers of Compound Nuclear States for R-Matrix Analyses. Bouland, Olivier; Larson, Nancy M.; Babut, Richard // AIP Conference Proceedings;2005, Vol. 769 Issue 1, p414 

    This paper reports the results of a collaborative effort between CEA of France and the DOE of the United States (in particular between le Laboratoire d’Etudes de Physique de Cadarache and the Nuclear Data Group at Oak Ridge National Laboratory): In preparing input for analyses of...

  • Application of the R-matrix method to photoionization of molecules. Tashiro, Motomichi // Journal of Chemical Physics;4/7/2010, Vol. 132 Issue 13, p134306 

    The R-matrix method has been used for theoretical calculation of electron collision with atoms and molecules for long years. The method was also formulated to treat photoionization process, however, its application has been mostly limited to photoionization of atoms. In this work, we implement...

  • The 12C(α, γ)16O E2 cross section at stellar energies. Descouvemont, P.; Dufour, M. // AIP Conference Proceedings;8/12/2010, Vol. 1269 Issue 1, p276 

    The E2 component of the 12C(α, γ)16O cross section is investigated by a microscopic cluster model, and by R-matrix fits. The first approach provides SE2(300 keV)≈50 keV-b for ground-state transitions. In the R-matrix theory, we show that the background term plays a crucial role, and...

  • 8Be Nuclear Data Evaluation. Page, Philip R.; Hale, Gerald M. // AIP Conference Proceedings;2005, Vol. 769 Issue 1, p390 

    An R-matrix analysis of experimental nuclear data on the reactions 4He(α,α), 4He(α,p), 4He(α,d), 7Li(p,α), 7Li(p,p), 7Li(p,n), 7Be(n,p), 6Li(d,α), 6Li(d,p), 6Li(d,n), and 6Li(d,d), leading to the 8Be intermediate state, has been completed in the last two years. About 4700 data...

  • Direct-Semidirect Neutron Capture Calculations Applied to R-Matrix Data Evaluations in the Resolved Resonance Region. Arbanas, G.; Dietrich, F. S.; Kerman, A. K. // AIP Conference Proceedings;2005, Vol. 769 Issue 1, p296 

    We present a method for computing direct-semidirect neutron radiative capture and its applications to R-Matrix evaluations of 19F, 27Al, 28,29,30Si, 35,37Cl, and 39,41K performed by the Nuclear Science and Technology Division’s Nuclear Data group at ORNL. The method includes both direct...

  • Upgrades to the R-Matrix Code SAMMY. Larson, N. M. // AIP Conference Proceedings;2005, Vol. 769 Issue 1, p286 

    The analysis code SAMMY is widely used for parameterization and understanding of neutron- and charged-particle-induced cross-section data. This report describes advances made in the development of the code: An overview of the main features of SAMMY is presented, with emphasis on options recently...

  • R-matrix calculations of differential and integral cross sections for low-energy electron collisions with ethanol. Fujimoto, M.M.; Brigg, W.J.; Tennyson, J. // European Physical Journal D -- Atoms, Molecules, Clusters & Opti;Aug2012, Vol. 66 Issue 8, p1 

    Electron collisions with CHOH are studied up to impact energies of 10 eV using several theoretical models. Calculated differential cross sections suggest that the extrapolation to low angles used to extend experimental data and hence give integral cross sections significantly underestimates the...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics