Measurement of neutron capture on {sup 48}Ca at thermal and thermonuclear energies
- Forschungszentrum Karlsruhe, Institut fuer Kernphysik, P.O. Box 3640, D-76021 Karlsruhe (Germany)
- Ente per le Nuove Tecnologie, l`Energia e l`Ambiente, Via Don Fiammelli 2, I-40128 Bologna (Italy)
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region (Russia)
- Institut fuer Kernphysik, Wiedner Hauptstrasse, 8-10, TU Wien, A-1040 Vienna (Austria)
At the Karlsruhe pulsed 3.75MV Van de Graaff accelerator the thermonuclear {sup 48}Ca({ital n},{gamma}){sup 49}Ca(8.72min) cross section was measured by the fast cyclic activation technique via the 3084.4keV {gamma}-ray line of the {sup 49}Ca decay. Samples of CaCO{sub 3} enriched in {sup 48}Ca by 77.87{percent} 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 218keV, respectively. Additionally, the thermal capture cross section was measured at the reactor BR1 in Mol, Belgium, via the prompt and decay {gamma}-ray lines using the same target material. The {sup 48}Ca({ital n},{gamma}){sup 49}Ca 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 {sup 49}Ca. The small coherent elastic cross section of {sup 48}Ca+{ital n} is explained through the nuclear Ramsauer effect. Spectroscopic factors of {sup 49}Ca have been extracted from the thermal capture cross section with better accuracy than from a recent ({ital d},{ital 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 {sup 49}Ca determined from shell-model calculations are compared with the values extracted from the experimental cross sections for {sup 48}Ca({ital d},{ital p}){sup 49}Ca and {sup 48}Ca({ital n},{gamma}){sup 49}Ca. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 385842
- Journal Information:
- Physical Review, C, Journal Name: Physical Review, C Journal Issue: 4 Vol. 54; ISSN PRVCAN; ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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