Dipole strength in La-139 below the neutron-separation energy

Abstract

The gamma-ray strength function is an important input quantity for the determination of the photoreaction rate and the neutron capture rate for astrophysics as well as for nuclear technologies. To test model predictions, the photoabsorption cross section of La-139 up to the neutron-separation energy was measured using bremsstrahlung produced at the electron accelerator ELBE of Forschungszentrum Dresden-Rossendorf with an electron beam of 11.5 MeV kinetic energy. The experimental data were analyzed by applying Monte Carlo simulations of gamma-ray cascades to obtain the intensities of the ground-state transitions and their branching ratios. We found a significant enhancement of electric dipole strength in the energy range from 6 to 10 MeV that may be related with a pygmy dipole resonance. The present data are combined with photoneutron cross sections for La-139 and compared with results of calculations on the basis of a quasiparticle-random-phase approximation using an instantaneous-shape sampling.

Department

Description

Provenance

Citation

Makinaga,A.;Schwengner,R.;Rusev,G.;Doenau,F.;Frauendorf,S.;Bemmerer,D.;Beyer,R.;Crespo,P.;Erhard,M.;Junghans,A. R.;Klug,J.;Kosev,K.;Nair,C.;Schilling,K. D.;Wagner,A.. 2010. Dipole strength in La-139 below the neutron-separation energy. Physical Review C 82(2): 24314-24314.

Published Version (Please cite this version)

10.1103/PhysRevC.82.024314


Unless otherwise indicated, scholarly articles published by Duke faculty members are made available here with a CC-BY-NC (Creative Commons Attribution Non-Commercial) license, as enabled by the Duke Open Access Policy. If you wish to use the materials in ways not already permitted under CC-BY-NC, please consult the copyright owner. Other materials are made available here through the author’s grant of a non-exclusive license to make their work openly accessible.