Study of the 187W states excited in the (n,γ) reaction

A singles γ-ray spectrum and a spectrum of summed amplitudes of coinciding pulses (SACP) were measured in the 186W (n, y) 187W reaction experiment on the thermal neutron beam. It was for the first time that the data on 187W γ-transitions were obtained in the excitation energy region from 1500-2500 keV. The neutron binding energy was determined to be Bn=5467.25 (4) keV (statistical error only). In result the level scheme of 187W was developed in the excitation energy interval 1<Ef<3.4 MeV, which contained 106 levels with about 70 of them being identified for the first time. The experimental values for summed intensities of two-step cascades were established to exceed those predicted by the modern statistical theory (by 36±6%). This is explained by a considerable contribution of few-quasiparticle components to wave functions of compound and intermediate states. (orig.)