Cross section measurement of the 144Sm(alpha,n)147Gd reaction for studying the alpha-nucleus optical potential at astrophysical energies

Abstract

Nuclear reactions involving alpha particles play an important role in various astrophysical processes such as the gamma-process of heavy element nucleosynthesis. The poorly known low-energy alpha-nucleus optical (AOMP) potential is a key parameter to estimate the rates of these reactions. The AOMP can be tested by measuring the cross section of alpha-scattering as well as alpha-induced reactions. Low energy elastic alpha-scattering on 144Sm has recently been measured with high precision. The aim of the present work was to complement that work by measuring the (a,n) cross sections on 144Sm at low energies. The experimental data shall be used to constrain the AOMP. From this potential the 144Sm(a,g)148Gd reaction rate can be derived with reduced uncertainties. The 144Sm(a,n)147Gd reaction was studied by bombarding Sm targets with alpha-beams provided by the cyclotron accelerator of Atomki. The cross section was determined using the activation method. The gamma-radiation following the decay of the 147Gd reaction product was measured with a HPGe detector. The experimental data are analyzed within the statistical model. The cross section was measured in the alpha-energy range between 13 and 20 MeV in 1 MeV steps, i.e., from close above the (a,n) threshold. The results were compared with statistical model calculations using various approaches and parametrizations for the AOMP, and excellent agreement was obtained for two recent potentials. However, these potentials cannot reproduce literature data for the 144Sm(a,g)148Gd reaction with the same accuracy. Constraints for the AOMP were derived from an analysis of the new 144Sm(a,n)147Gd data and literature data for 144Sm(a,g)148Gd. These constraints enable a determination of the reaction rate of the 144Sm(a,g)148Gd reaction with significantly reduced uncertainties of less than a factor of two.

arXiv commentAccepted for publication in Phys. Rev. C

References in corpus (26)

• Astrophysical Reaction Rates From Statistical Model Calculations
• The s Process: Nuclear Physics, Stellar Models, Observations
• Origin of the Heaviest Elements: the Rapid Neutron-Capture Process
• Constraining the astrophysical origin of the p-nuclei through nuclear physics and meteoritic data
• STARLIB: A Next-Generation Reaction-Rate Library for Nuclear Astrophysics
• A Shorter 146Sm Half-Life Measured and Implications for 146Sm-142Nd Chronology in the Solar System
• Type Ia Supernovae as Sites of p-process: Two-Dimensional Models Coupled to Nucleosynthesis
• Further explorations of the alpha-particle optical model potential at low energies for the mass range A=45-209
• The Path to Improved Reaction Rates for Astrophysics
• Relevant energy ranges for astrophysical reaction rates
• The ^{144}Sm-αoptical potential at astrophysically relevant energies derived from ^{144}Sm(α,α)^{144}Sm elastic scattering
• Uncertainties in the production of $p$ nuclei in massive stars obtained from Monte Carlo variations
• The activation method for cross section measurements in nuclear astrophysics
• Determination of 141Pr(alpha,n)144Pm cross sections at energies of relevance for the astrophysical p-process using the gamma-gamma coincidence method
• Elastic alpha scattering experiments and the alpha-nucleus optical potential at low energies
• Origin of the p-process radionuclides 92Nb and 146Sm in the early Solar System and inferences on the birth of the Sun
• Successful prediction of total $\alpha$-induced reaction cross sections at astrophysically relevant sub-Coulomb energies using a novel approach
• Solution of the alpha-potential mystery in the gamma-process and its impact on the Nd/Sm ratio in meteorites
• Cross sections of $\alpha$-induced reactions for targets with masses $A\approx 20-50$ at low energies
• Constraining nucleosynthesis in neutrino-driven winds: observations, simulations and nuclear physics
• Investigation of $\alpha$-induced reactions on Sb isotopes relevant to the astrophysical $\gamma$-process
• Statistical model analysis of $\alpha$-induced reaction cross sections of ${}^{64}$Zn at low energies
• Cross section of $\alpha$-induced reactions on ${}^{197}$Au at sub-Coulomb energies
• Total reaction cross sections from ${}^{141}$141Pr($\alpha$,$\alpha$)${}^{141}$Pr elastic scattering and $\alpha$-induced reaction cross sections at low energies
• Measurement of the 91Zr(p,gamma)92mNb cross section motivated by type Ia supernova nucleosynthesis
• Cross sections of $\alpha$-induced reactions slightly below doubly-magic ${}^{40}$Ca from the statistical model

Cited by in corpus (2)

• Bayesian Analysis of the ${}^{86}$Sr$(\alpha ,\alpha )$ Reaction to Constrain the ${}^{86}$Sr$(\alpha ,n)$ Cross Section at Astrophysical Energies
• Excitation function measurement of ${}^{144}$Sm($\alpha$,n) reaction at sub-Coulomb energies and detailed covariance analysis