Measurement of the 187Re(α,n)190Ir reaction cross section at sub-Coulomb energies using the Cologne Clover Counting Setup

Abstract

Uncertainties in adopted models of particle+nucleus optical-model potentials directly influence the accuracy in the theoretical predictions of reaction rates as they are needed for reaction-network calculations in, for instance, γ-process nucleosynthesis. The improvement of the α+nucleus optical-model potential is hampered by the lack of experimental data at astrophysically relevant energies especially for heavier nuclei. Measuring the Re187(α,n)Ir190 reaction cross section at sub-Coulomb energies extends the scarce experimental data available in this mass region and helps understanding the energy dependence of the imaginary part of the α+nucleus optical-model potential at low energies. Applying the activation method, after the irradiation of natural rhenium targets with α-particle energies of 12.4 to 14.1 MeV, the reaction yield and thus the reaction cross section were determined via γ-ray spectroscopy by using the Cologne Clover Counting Setup and the method of γγ coincidences. Cross-section values at five energies close to the astrophysically relevant energy region were measured. Statistical model calculations revealed discrepancies between the experimental values and predictions based on widely used α+nucleus optical-model potentials. However, an excellent reproduction of the measured cross-section values could be achieved from calculations based on the so-called Sauerwein-Rauscher α+nucleus optical-model potential. The results obtained indicate that the energy dependence of the imaginary part of the α+nucleus optical-model potential can be described by an exponential decrease. Successful reproductions of measured cross sections at low energies for α-induced reactions in the mass range 141{\leq}A{\leq}187 confirm the global character of the Sauerwein-Rauscher potential.

References in corpus (17)

• Nucleosynthesis in Massive Stars With Improved Nuclear and Stellar Physics
• Astrophysical Reaction Rates From Statistical Model Calculations
• Neutron capture in low mass Asymptotic Giant Branch stars: cross sections and abundance signatures
• Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity
• Constraining the astrophysical origin of the p-nuclei through nuclear physics and meteoritic data
• Type Ia Supernovae as Sites of p-process: Two-Dimensional Models Coupled to Nucleosynthesis
• The Path to Improved Reaction Rates for Astrophysics
• Sensitivity of astrophysical reaction rates to nuclear uncertainties
• Alpha-induced cross sections of 106Cd for the astrophysical p-process
• Odd p isotope 113In: Measurement of alpha-induced reactions
• Determination of 141Pr(alpha,n)144Pm cross sections at energies of relevance for the astrophysical p-process using the gamma-gamma coincidence method
• Alpha-induced reaction cross section measurements on 151Eu for the astrophysical gamma-process
• Determining reaction cross sections via characteristic X-ray detection: α-induced reactions on 169Tm for the astrophysical γ -process
• Cross section measurements of $\alpha$-induced reactions on ${}^{92,94}$Mo and ${}^{112}$Sn for $p$-process studies
• Investigation of alpha-induced reactions on the p nucleus 168Yb
• Solution of the alpha-potential mystery in the gamma-process and its impact on the Nd/Sm ratio in meteorites
• Astrophysical analysis of the measurement of (alpha,gamma) and (alpha,n) cross sections of 169Tm

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