Measurement of neutron capture on Ca48 at thermal and thermonuclear energies

H. Beer, C. Coceva, P. V. Sedyshev, Yu. P. Popov, H. Herndl, R. Hofinger, P. Mohr, and H. Oberhummer
Phys. Rev. C 54, 2014 – Published 1 October 1996
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Abstract

At the Karlsruhe pulsed 3.75 MV Van de Graaff accelerator the thermonuclear Ca48(n)49Ca(8.72 min) cross section was measured by the fast cyclic activation technique via the 3084.4 keV γ-ray line of the Ca49 decay. Samples of CaCO3 enriched in Ca48 by 77.87% were irradiated between two gold foils which served as capture standards. The capture cross section was measured at the neutron energies 25, 151, 176, and 218 keV, respectively. Additionally, the thermal capture cross section was measured at the reactor BR1 in Mol, Belgium, via the prompt and decay γ-ray lines using the same target material. The Ca48(n)49Ca cross section in the thermonuclear and thermal energy range has been calculated using the direct-capture model combined with folding potentials. The potential strengths are adjusted to the scattering length and the binding energies of the final states in Ca49. The small coherent elastic cross section of Ca48+n is explained through the nuclear Ramsauer effect. Spectroscopic factors of Ca49 have been extracted from the thermal capture cross section with better accuracy than from a recent (d,p) experiment. Within the uncertainties both results are in agreement. The nonresonant thermal and thermonuclear experimental data for this reaction can be reproduced using the direct-capture model. A possible interference with a resonant contribution is discussed. The neutron spectroscopic factors of Ca49 determined from shell-model calculations are compared with the values extracted from the experimental cross sections for Ca48(d,p)49Ca and Ca48(n)49Ca. © 1996 The American Physical Society.

  • Received 29 April 1996

DOI:https://doi.org/10.1103/PhysRevC.54.2014

©1996 American Physical Society

Authors & Affiliations

H. Beer

  • Forschungszentrum Karlsruhe, Institut für Kernphysik, P.O. Box 3640, D-76021 Karlsruhe, Germany

C. Coceva

  • Ente per le Nuove Tecnologie, l'Energia e l'Ambiente, Via Don Fiammelli 2, I-40128 Bologna, Italy

P. V. Sedyshev and Yu. P. Popov

  • Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia

H. Herndl, R. Hofinger, P. Mohr, and H. Oberhummer

  • Institut für Kernphysik, Wiedner Hauptstrasse, 8-10, TU Wien, A-1040 Vienna, Austria

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Vol. 54, Iss. 4 — October 1996

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