Stellar neutron capture rates of sup(148,149,150)Sm

We have measured to a precision of proportional 4.5% the neutron capture cross sections of sup(148,149,150)Sm over the neutron energy range 4<Esub(n)<250 keV. These data, in conjunction with calculated cross sections for 147Nd and sup(147,148)Pm, are used to establish a set of Maxwellian-averaged cross section useful for investigation of the element synthesis in the s-process around Aproportional150. The ratio of the values of the s-process current anti sigmasub(γ)Nsub(s) (Maxwellian-averaged neutron cross section times s-process abundance) for the s-only isotopes sup(148,150)Sm is 0.91+-0.03, rather than unity as predicted by the local approximation. We interpret this result as due to an s-process branching which partly bypasses 148Sm. Since the beta decay rates at the branching points are expected to be almost independent of temperature, we are able to obtain an estimate of the s-process neutron density of nsub(n)=(1.0+-0.4)x108 cm-3. The new results have also served to considerably improve the anti sigmasub(γ)Nsub(s)-systematics in the mass region 145<A<150. (orig.)