Abstract:
The neutron capture cross sections of unstable nuclei are important to the study of the stellar nucleosynthesis and the neutron densities in massive stars. Due to the difficulties of the target fabrication, it is very hard to measure the neutron capture cross section of unstable nuclei directly. Therefore, the surrogate ratio method had been employed in (n, γ) determination and proved valid previously. In this work, the difference of the spin-parity distribution in compound nuclei that formed by surrogate reaction or neutron capture was discussed in (n, γ) determination with surrogate ratio method. The γ-decay probabilities ratio of
92Zr* and
94Zr* were calculated in various spin-parities, and the calculation showed the ratio is insensitive to their spin-parity distribution in high incident neutron energies. The measured γ-decay probabilities ratios of
92Zr* and
94Zr* were compared to the theoretical calculations, it imply that the spin-parity distributions of compound nuclei formed by (
18O,
16O) reactions are similar to the one formed by neutron captures, and the validity of the surrogate ratio method was further proved in this work.