Experimental and theoretical study of the ${}^{65}\mathrm{Cu}\left(n,p\right){}^{65}\mathrm{Ni}$ reaction cross section from reaction threshold up to 25 MeV

The cross section of the ${}^{65}\mathrm{Cu}\left(n,p\right){}^{65}\mathrm{Ni}$ reaction was studied experimentally at three different neutron energies using an activation technique. The quasimonoenergetic neutrons were produced via the ${}^7\mathrm{Li}\left(p,n\right)$ reaction at the 14UD BARC-TIFR Pelletron facility in Mumbai, India. Al monitor foils along with Cu samples were activated to determine the incident neutron flux. The activities of the reaction products were measured using a high resolution high purity germanium spectrometry system. Statistical model calculations were performed using the reaction codes talys (ver. 1.9) and empire (ver. 3.2.3) from the reaction threshold to the neutron energy of 25 MeV. Additionally, the effects of various combinations of the theoretical nuclear level densities (NLDs), optical model potentials (OMPs), preequilibrium models (PEs), and γ-ray strength functions (γ SFs) were considered for the reproduction of experimental data. The input parameters needed in theoretical calculations to reproduce the present and previous measurements were taken from the RIPL-3 database. The present results are compared with the previous measurements, with the latest evaluations of the ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0/HE, CENDL-3.2, TENDL-2019, and FENDL-3.2 libraries, and with the theoretically calculated values based on talys and empire codes. Furthermore, the cross section of the ${}^{65}\mathrm{Cu}\left(n,p\right){}^{65}\mathrm{Ni}$ reaction was estimated within the neutron energies of 14–15 MeV using different systematic formulas. These estimated cross sections by various systematic formulas were compared with the available experimental data. The present data will help to understand the nuclear reaction theory (models) in higher energy regions and improve the evaluated nuclear data evaluation that is needed for fundamental nuclear applications.

Figure 1

The previous experimental cross section from EXFOR and evaluated from the ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0/HE, CENDL-3.2, TENDL-2019, and FENDL-3.2 libraries for the ${}^{65}\mathrm{Cu}\left(n,p\right){}^{65}\mathrm{Ni}$ reaction cross section from the reaction threshold to 20 MeV.

Figure 2

The schematic diagram of the experimental setup for neutron irradiation of the samples.

Figure 3

The efficiency calibration curve of the HPGe detector with and without coincidence summing effect correction factor Kc.

Figure 4

Neutron spectra at 16, 19, and 22 MeV proton energies are obtained from the Refs. [34, 35, 36, 37, 38].

Figure 5

Comparison of the present data with the previous measurements taken from the EXFOR compilation, data of Grimes et al., and the evaluated data from the ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0/HE, CENDL-3.2, TENDL-2019, and FENDL-3.2 libraries.

Figure 6

The present ${}^{65}\mathrm{Cu}\left(n,p\right){}^{65}\mathrm{Ni}$ reaction cross section along with the experimental data and theoretical values based on the (a), (b) talys and (c), (d) empire codes with the default option.

Figure 7

The present ${}^{65}\mathrm{Cu}\left(n,p\right){}^{65}\mathrm{Ni}$ reaction cross section along with the experimental data and adjusted theoretical values obtained from the (a), (b) talys and (c), (d) empire codes with adjusted parameters.

Figure 8

Comparison of the activation cross section [7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21] and total proton emission cross sections [78] with the theoretical calculations performed by the talys code.

Figure 9

The contribution of the cross section in the ${}^{65}\mathrm{Cu}\left(n,p\right){}^{65}\mathrm{Ni}$ reaction from different reaction processes (direct, preequilibrium, and compound) to the total reaction cross section was calculated using the talys code.