The stellar (n,gamma) cross section of 62Ni

The 62Ni(n,gamma)63Ni(t_1/2=100+-2 yrs) reaction plays an important role in the control of the flow path of the slow neutron-capture (s-) nucleosynthesis process. We have measured for the first time the total cross section of this reaction for a quasi-Maxwellian (kT = 25 keV) neutron flux. The measurement was performed by fast-neutron activation, combined with accelerator mass spectrometry to detect directly the 63Ni product nuclei. The experimental value of 28.4+-2.8 mb, fairly consistent with a recent theoretical estimate, affects the calculated net yield of 62Ni itself and the whole distribution of nuclei with 62<A <90 produced by the weak s-process in massive stars.