⁹⁵Zr, ¹⁴⁰Ba, and ¹⁴⁷Nd Yields From 0.57, 1.0, and 1.5 MeV Neutrons Induced Fission of ²³⁵U

The yields of fission products(Y) ⁹⁵Zr, ¹⁴⁰Ba, and ¹⁴⁷Nd were absolutely determined using γ-spectrum method for the ²³⁵U fission induced by 0.57, 1.0, and 1.5 MeV neutrons, respectively. The γ spectra were measured by a P-type coaxial HPGe detector with the volume of 110 cm³ and the resolution of 1.8 keV at 1332.5 keV, and the acquired γ-spectra were analyzed by the SPAN code. The fission rate in the fission process was monitored with a double-fission ionization chamber. The impacts of some factors on the fission yield data were analyzed, specially. The neutron spectrum in the uranium sample was simulated with MCNP IVB code, and the effects from other secondary neutrons were also analyzed. Finally, the determined fission yields are given as following: the Y(⁹⁵Zr)=(6.64±0.21)%, Y(¹⁴⁰Ba)=(6.37±0.22)%, Y(¹⁴⁷Nd)=(2.37±0.08)% for 0.57 MeV neutron; Y(⁹⁵Zr)=(6.49±0.19)%, Y(¹⁴⁰Ba)=(6.35±0.18)%, Y(¹⁴⁷Nd)=(2.25±0.07)% for 1.0 MeV neutron; Y(⁹⁵Zr)=(6.59±0.19)%, Y(¹⁴⁰Ba)=(6.25±0.18)%, Y(¹⁴⁷Nd)=(2.37±0.07)% for 1.5 MeV neutron. The variations of Y (⁹⁵Zr/¹⁴⁰Ba/¹⁴⁷Nd) with neutron energy were analyzed and discussed.