Charge distribution of light mass fission products in the fast neutron induced fission of Np, Am and Am.

In the fast neutron induced fission of Np, Am and Am, fractional cumulative yields (FCY) of various light mass fission products have been measured for the first time by using an off-line γ-ray spectrometric technique. The most probable charge (Z) and the experimental charge polarization (ΔΖ) as a function of fragment mass were obtained. The ΔΖ values for the light mass chains from the present work and for the heavy mass chains from earlier work show a decreasing trend towards symmetric split with fluctuations for some of the mass chains due to the effect of shell closure proximity. The ΔΖ values based on minimum potential energy surface were theoretically calculated, which also shows a systematic decrease trend with the approach of symmetric split without any fluctuation due to the liquid drop behaviour of the fissioning nucleus.