A STRONG ISOTOPIC EFFECT IN PRESCISSION CHARGED-PARTICLE MULTIPLICITIES

In the framework of the Combined Dynamical Statistical (Langevin - Mon te-Carlo) Model we investigate two properties of the multiplicities of light particles (neutrons, protons and alpha) accompanying the fissio n process: their dependence on the spin of the compound nucleus (CN) a nd on the neutron number of CN at a fixed proton number. Calculations are performed for fission of Cf-246-258 induced by alpha-particles and by heavy ions. No noticeable dependence on the spin distribution has been found, whereas the isotopic dependence turned out to be very stro ng. These conclusions can be considered as theoretical predictions for experiments planned to be performed in the near future using protons and alpha-particle beams.