Post-Neutron Mass Yield Distribution in the Thermal Neutron Induced Fission of 232U

초록

In the thermal neutron-induced fission of U-232, cumulative and independent yields of various fission products within the mass ranges of 72 to 107 and 123 to 158 have been measured using an off-line gamma-ray spectrometric technique. The fission yields were determined relative to the yield of a monitor product Sr-92. Charge distribution correction was applied on the cumulative yields to obtain the post-neutron mass yield distribution. Mass yield distribution parameters such as full-width at tenth-maximum of light and heavy mass wings, average light mass number and heavy mass number , and average number of emitted neutrons were obtained. Data from the present and earlier work on the U-232(n(th),f) reaction were compared with similar data of the U-235(n(th),f) reaction. It was found that the mass chain yield distribution in the U-232(n(th),f) reaction is asymmetric with two major humps as in the case of the U-235(n(th),f) reaction. Besides this, in the U-232(n(th),f) reaction, the mass yield distribution shows a small third hump for the symmetric fission products. It was also found that the standard II asymmetric mode of fission is favorable in the U-232(n(th),f) reaction whereas the standard I asymmetric mode of fission is favorable in the U-235(n(th),f) reaction.

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