Fission product yields in nuclear reactions induced by intermediate energy particles

The calculation of fission product yields for reactions induced by intermediate energy particles have been performed with the help of the Fong statistical model and different approaches for nuclear level density calculations. The Fermi-gas model, the generalized superfluid model and an approximate approach were applied to obtain the nuclear level densities of fission fragments. It is shown that the approaches disregarding the attenuation of the shell effects in nuclei with increasing excitation energy do not describe the experimental fission product yields in an appropriate way. A new phenomenological approach has therefore been proposed for fission product yield calculations in the intermediate energy region of primary particles. The predictions of the approach are in a good agreement with available experimental data. (orig.)