Measurement of the ${}^{72}$Ge(n,γ) cross section over a wide neutron energy range at the CERN n_TOF facility

The ${}^{71}$ Ge(n,γ) cross section was measured for neutron energies up to 300keV at the neutron time-of-flight facility n_TOF (CERN), Geneva, for the first time covering energies relevant to heavy-element synthesis in stars. The measurement was performed at the high-resolution beamline EAR-1, using an isotopically enriched ${}^{72}$GeO${}_2$ sample. The prompt capture γ rays were detected with four liquid scintillation detectors, optimized for low neutron sensitivity. We determined resonance capture kernelsup to a neutron energy of 43keV, and averaged cross sections from 43 to 300keV. Maxwellian-averaged cross section values were calculated from kT=5 to 100keV, with uncertainties between 3.2% and 7.1 %. The new results significantly reduce uncertainties of abundances produced in the slow neutron capture process in massive stars.