Measurement of the ${}^{70}$Ge($n,\gamma$) cross section up to 300~keV at the CERN n_TOF facility

Abstract

Neutron capture data on intermediate mass nuclei are of key importance to nucleosynthesis in the weak component of the slow neutron capture processes, which occurs in massive stars. The ($n,\gamma$) cross section on ${}^{70}$Ge, which is mainly produced in the $s$~process, was measured at the neutron time-of-flight facility n_TOF at CERN. Resonance capture kernels were determined up to 40~keV neutron energy, and average cross sections up to 300~keV. Stellar cross sections were calculated from $kT=5$~keV to $kT=100$ keV and are in very good agreement with a previous measurement by Walter and Beer (1985), and recent evaluations. Average cross sections are in agreement with Walter and Beer (1985) over most of the neutron energy range covered, while being systematically smaller for neutron energies above 150~keV. We have calculated isotopic abundances produced in $s$-process environments in a 25 solar mass star for two initial metallicities (below solar, and close to solar). While the low metallicity model reproduces best the solar system germanium isotopic abundances the close to solar model shows a good global match to solar system abundances between mass numbers A=60-80.

References in corpus (11)

• Neutron capture in low mass Asymptotic Giant Branch stars: cross sections and abundance signatures
• 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
• Neutron Reactions in Astrophysics
• Sensitivity of astrophysical reaction rates to nuclear uncertainties
• Relationships between HI Gas Mass, Stellar Mass and Star Formation Rate of HICAT+WISE (HI-WISE) Galaxies
• Uncertainties in s-process nucleosynthesis in massive stars determined by Monte Carlo variations
• Uncertainties in s-process nucleosynthesis in low mass stars determined from Monte Carlo variations
• Pulse processing routines for neutron time-of-flight data
• GEANT4 simulation of the neutron background of the C${}_6$D${}_6$ set-up for capture studies at n_TOF
• Measurement of 73Ge(n,g) cross sections and implications for stellar nucleosynthesis

Cited by in corpus (2)

• The Status and Future of Direct Nuclear Reaction Measurements for Stellar Burning
• Stellar ${\beta }^{-}$-decay rate of ${}^{63}$Ni and its impact on the $s$-process nucleosynthesis in massive stars