Absolute Measurement of ⁹⁹Mo Fission Yields of ²³⁵U Induced by 0.57, 1.0 and 1.5 MeV Neutrons

The chain yields of fission product ⁹⁹Mo were determined for the fission of ²³⁵U induced by 0.57, 1.0 and 1.5 MeV neutrons. Absolute fission rate was monitored with a double-fission chamber. Fission product activities were measured by HPGe γ-ray spectrometry. MCNP ⅣB was applied to simulate neutron spectrum in uranium samples, and the effects of all kinds of secondary neutrons on fission yield data were discussed. The fission yields of ⁹⁹Mo for 0.57, 1.0 and 1.5 MeV neutrons are 6.61%, 6.62% and 6.28%, respectively. The yield data were compared with those of ANL. Our results are in agreement with those of ANL within the scope of experimental uncertainties after necessary corrections.