Abstract:
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 cm
3 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.