Search

Two methods used to subtract the effect of the decay of different nuclear reaction products on the cross-section measurement of the studied nuclear reaction were given. Taking the cross-section measurement of the $^{91}\mathrm{Zr}(n,p)^{91\mathrm{m}}\mathrm{Y}$ reaction as an example, the accurate and reliable cross section of the $^{91}\mathrm{Zr}(n,p)^{91\mathrm{m}}\mathrm{Y}$ reaction in the neutron energy range of 13.5--14.8 MeV was measured by using the activation technique and the above two methods. Moreover, the excitation function in the neutron energies from the threshold to 21 MeV was calculated by using the nuclear theoretical model program system talys--1.9 with the adjusted relevant parameters. The measured cross-section values were discussed and compared with previous experiments by other researchers and with the theoretical values based on talys--1.9. The experimental values obtained by the above two methods were highly consistent within experimental error, and at some neutron energies they were consistent, within experimental error, with those of the fitting line of previous experiments at the corresponding energies, and were also consistent with those of theoretical excitation curve at the corresponding energies. The obtained theoretical excitation curve can match most of the experimental data.

The first experimental cross-section data for the 180Hf(n,γ)181Hf reaction have been measured within the neutron energies range of 13.5–14.8 MeV using the activation technique. The fast neutrons were produced by the T(d,n)4He reaction. Induced activities were measured by a high-resolution γ-ray spectrometer with high-purity germanium detector. The neutron fluence was determined by using the monitor reaction 93Nb(n,2n)92mNb. The neutron energies in the measurements were determined beforehand by the method of cross section ratios for the 90Zr(n,2n)89m+gZr and 93Nb(n,2n)92mNb reactions. The experimentally determined cross-section values were compared with the evaluation nuclear data in several major libraries of International Atomic Energy Agency and the theoretically calculated results by using the Talys1.8 code.

The cross sections for the 94Zr(n,d*)93m+gY, 96Zr(n,γ)97Z, 96Zr(n,2n)95Zr, 90Zr(n,α)87mSr, 94Zr(n,α)91Sr,90Zr(n,p)90mY, 92Zr(n,p)92Y, and 94Zr(n,p)94Y reactions have been measured in the neutron energy range of 13.5-14.8 MeV by means of the activation technique. The neutrons were produced via the D-T reaction. A high-purity germanium detector with high energy resolution was used to measure the induced γ activities. In combination with the nuclear reaction theoretical models, the excitation curves of the above-mentioned eight nuclear reactions within the incident neutron energy range from the threshold to 20 MeV were obtained by adopting the nuclear theoretical model program system Talys-1.9. The resulting experimental cross sections were analyzed and compared with the experimental data from published studies. Calculations were performed using Talys-1.9 and are in agreement with our experimental results, previous experimental values, as well as results of the theoretical excitation curves at the corresponding energies. The theoretical excitation curves generally match the experimental data well.

In view of the fact that the fast-neutron experimental cross-section data of hafnium which is an important structural material of fusion reactor are few and there are the great differences in their evaluation values, several activation cross sections of (n, 2n), (n, p), (n, a) and (n, n′) reactions on hafnium isotopes have been investigated by neutrons generated from the T(d, n)4He reaction at the K-400 Neutron Generator at China Academy of Engineering Physics (CAEP). The gamma activities of the product nuclei were measured by a high-resolution gamma-ray spectrometer with a coaxial high-purity germanium detector. The 93Nb(n, 2n)92mNb reaction was used as neutron fluence standard, these experimental cross sections of the 174Hf(n, 2n)173Hf, 176Hf(n, 2n)175Hf, 178Hf(n, α)175m+gYb, 178Hf(n, p)178gLu, 178Hf(n, p)178mLu, 180Hf(n, 2n)179m2Hf, 180Hf(n, α)177m+gYb and 180Hf(n, n′)180mHf reactions were obtained in the neutron energy range of 13.5–14.8 MeV. These measured cross sections were discussed and compared with some previous experimental results from the literature and with the evaluation data from ENDF/B-VIII.0, CENDL-3.1, JEFF-3.3 and the theoretical results by using the computer code system Talys-1.9.