Resonant neutron capture in 139La

The neutron capture cross section of 139La has been measured with high energy resolution between 2.5 and 90 keV using the capture cross section facility at the 40 m station on the Oak Ridge Electron Linear Accelerator. Individual resonances were analysed to 15 KeV and the average s- and p-wave radiative widths deduced were sub(s) = 55+-6 MeV and sub(p) = 40+-7 meV. The p-wave neutron strength function obtained was S1 = (0.30+-0.l0)x104. The s-wave resonances decay strongly to final f-wave states via a postulated doorway state mechanism. The transition strengths for these decays are not correlated with the neutron widths of the initial states. (Author)