Neutron capture cross sections of the cerium isotopes for {ital s}- and {ital p}-process studies

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.53.1397· OSTI ID:279140

Kaeppeler, F; Toukan, K A; Schumann, M ^[1]; Mengoni, A ^[2]

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1. Forschungszentrum Karlsruhe, Institut fuer Kernphysik, Postfach 3640, D-76021 Karlsruhe (Germany)
2. Comitato Nazionale per la Ricerca e per lo Sviluppo dellEnergia Nucleare e delle Energie Alternative (ENEA), Settore Fisica Applicata, V. Ercolani 8, I-40138 Bologna (Italy)

The neutron capture cross sections of the stable cerium isotopes 136, 138, 140, and 142 have been measured relative to that of gold by means of the activation method. The samples were irradiated in a quasistellar neutron spectrum for {ital kT}=25 keV using the {sup 7}Li({ital p},{ital n}){sup 7}Be reaction near threshold. Variation of the experimental conditions in different activations and the use of different samples allowed for the reliable determination of corrections and the evaluation of systematic uncertainties. The resulting stellar cross sections can be given with uncertainties between 3{percent} and 7{percent}. The present data for {sup 136}Ce and {sup 138}Ce are the first experimental information in this mass region of relevance for {ital p}-process studies to our knowledge, whereas the new {sup 142}Ce cross section allowed to resolve a previous discrepancy. The experimental results are complemented by a set of calculated cross sections for all cerium isotopes from {sup 132}Ce to {sup 142}Ce as well as for {sup 141}Pr, {sup 142}Pr, and {sup 143}Pr. The improved cross sections were used in an updated {ital s}-process analysis of the Ce-Pr-Nd region that included the small branchings at {sup 141}Ce and {sup 142}Pr. The consequences of the resulting {ital s} abundances are discussed with respect to isotopic anomalies in meteoritic neodymium as well as for the {ital r}- and {ital p}-process residuals. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 279140
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 3 Vol. 53; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BERYLLIUM 7
CAPTURE
CERIUM ISOTOPES
CROSS SECTIONS
LITHIUM 7 TARGET
NEUTRON SPECTRA
NEUTRONS
PRASEODYMIUM ISOTOPES
PROTON REACTIONS
S PROCESS