Delayed neutron yields and spectra from photofission of actinides: data and calculations with Bremsstrahlung photons below 20 MeV

Abstract. Photonuclear reactions, especially photofission delayed neutron emission, play an important role for applications involving nuclear material detection. In order to provide good quality data for evaluations and data libraries, an experimental program of delayed neutron measurements has been undertaken for actinides with Bremsstrahlung energy from 12 up to 20 MeV. In this paper, we report on delayed neutron yields and time spectra characteristics from the photofission of 238U and 235U for several endpoint energies between 12 and 18.5 MeV. The associated modelling efforts will be described including some calculations compared to experimental data.