Fission product yields in nuclear reactions induced by intermediate energyparticles

The calculation of fission product yields for reactions induced by intermed iate energy particles have been performed with the help of the Fong statist ical model and different approaches for nuclear level density calculations. The Fermi-gas model, the generalized superfluid model and an approximate a pproach were applied to obtain the nuclear level densities of fission fragm ents. it is shown that the approaches disregarding the attenuation of the s hell effects in nuclei with increasing excitation energy do not describe th e experimental fission product yields in an appropriate way. A new phenomen ological approach has therefore been proposed for fission product yield cal culations in the intermediate energy region of primary particles The predic tions of the approach are in a goon agreement with available experimental d ata.