Estimation of the 237Np(n,2n)/[237Np(,n)+237Np(n,2n)] reaction rate ratio in the mixed n- fields associated with the thermal neutron induced fission of 235U and the spontaneous fission of 252Cf

The 237Np(y,n) cross-section has been folded with the fissiongamma- spectra from the mU(nth,f) and 2525Cf (sf) systems in order to estimate the 237Np(n,2n)/[237Np(y,n) + 237Np(n,2n)] reaction rate ratio expected in integral cross-section determinations. The (y,n) contribution was shown to be small at about 1%.