Charge distribution in thermal neutron induced fission of 241Pu : determination of fractional cumulative yields of 135I and 140Ba

The fractional cumulative yields of 135I and 140Ba in the thermal neutron induced fission of 241Pu have been determined gamma-spectrometrically following growth and decay of the respective daughter products. The determined yield values are 0.9668 +-0.0061 and 0.9939 +- 0.00O6 for 135I and 140Ba respectively. The fractional cumulative yield of 135I indicates a narrow width of charge distribution in the mass chain 135 while the yield of 140Ba indicates a broad width of the distribution in the mass chain 140. The variation in the widths of charge distribution in these two mass-chains has been discussed in terms of 82 neutron shell effect and nucleon-pairing effect. (author)