Post-Neutron Mass Yield Distribution in the Epi-Cadmium Neutron-Induced Fission of 235U

초록

Cumulative and independent yields of various fission products within the mass ranges of 78 to 117 and 123 to 155 have been measured in the epi-cadmium reactor neutron-induced fission of U-235 by using an off-line gamma-ray spectrometric technique. The average neutron energy <E-n> of the epi-cadmium reactor spectrum is 1.9 MeV. From the cumulative yields, post-neutron mass chain yields were obtained by applying the charge distribution correction. In the mass yield distribution, values of the full-width at tenth-maximum of light and heavy mass wings, average light mass <A(L)> and heavy mass <A(H)>, and average number of neutrons <nu> were obtained. The peak-to-valley ratio in the epi-cadmium neutron-induced fission of U-235 was obtained for the first time. The present data in the U-235(n,f) reaction were compared with the literature data in the U-235(n(th),f) reaction to examine the role of excitation energy on the mass yield distribution parameters and nuclear structure effect. The role of the standard I and standard II asymmetric modes of fission was also discussed.

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