Charge distribution of heavy mass fission products in the thermal neutron induced fission of 233 U, 235 U and 239 Pu

Isobaric charge distribution has been carried out in the thermal neutron induced fission of U, U and Pu by measuring the fractional cumulative yields (FCY) of various heavy mass fission products within the range of 127-149. An off-line γ-ray spectrometric technique was used for the measurement of fission product activities. The width of the isobaric charge distribution (σ ), most probable charge (Z ) and thus the experimental charge polarization (ΔΖ ) as a function of fragment mass were obtained. It was found that the σ values around the mass number 127-129 and 132-136 are lower due to the presence of spherical 50p and 82n shells. The ΔΖ values show an oscillating nature in the interval of five mass units due to even-odd effect. The ΔΖ values also show a decreasing trend with the approach of symmetric split besides an oscillating nature. The most probable charge (Z ) and thus the ΔΖ values based on the minimum potential energy surface were theoretically calculated, which show a systematic decreasing trend with the approach of symmetric split due to the liquid drop behaviour of the fissioning nucleus.