Systematic analysis of the neutron-induced reaction cross sections for ${}^{\mathrm{nat}}\mathrm{Mo}$ isotopes within 10–20 MeV

The production cross sections for the medical isotope ${}^{99}\mathrm{Mo}$ were measured using the ${}^{100}\mathrm{Mo}(n,2n)$ reaction at average neutron energies of $10.95\pm 0.45, 13.97\pm 0.68, 16.99\pm 0.53$, and $20.00\pm 0.58$ MeV using offline $\gamma$-ray spectroscopy. The neutron beam was generated using the ${}^{\mathrm{nat}}\mathrm{Li}(p,n)$ reaction at the 14UD BARC-TIFR Pelletron facility, Mumbai, India. The uncertainties in the measured data were calculated using covariance analysis. The experimental results were compared with the existing data libraries ENDF/B-VII.1, JENDL-4.0, JEFF-3.2, and CENDL-3.1. The present results were also reproduced and compared with the theoretical nuclear model codes talys-1.9 and alice-2017 using different input descriptions. A modified set of parameters were also used in talys-1.9 to fit the existing data more accurately. The present findings show a good agreement with the theoretical predictions and with the existing experimental results from the different data libraries. In addition to this, a comparative study have also been performed between the literature data of $(n,p), (n,2n)$, and $(n,\alpha )$ reaction cross sections at 14.5 MeV using various systematic formulas. The outcomes of the present work are important for the advancement of medical accelerators, dosimetry, and fast reactor systems.

Figure 1

Schematic diagram of the experimental setup used for the irradiations.

Figure 2

Neutron spectra generated from the ${}^{\mathrm{nat}}\mathrm{Li}(p,n)$ reaction using the four proton energies used for the irradiations

Figure 3

The typically recorded spectra for the monitor and sample reactions.

Figure 4

(a) Measured detector efficiency and (b) the comparison of measured uncertainty in efficiencies ($\mathrm{\Delta }{\varepsilon }_i/{\varepsilon }_i$) with the uncertainty in the detector efficiencies relative to the monitor efficiency ($\mathrm{\Delta }{\eta }_{i,m}/{\eta }_{i,m}$)

Figure 5

A comparison of the present experimental ${}^{100}\mathrm{Mo}(n,2n){}^{99}\mathrm{Mo}$ reaction cross sections with the literature data [13, 14, 15, 16, 17, 18, 19, 20, 21, 22], and with the theoretical values from different ldmodels in talys-1.9 [28].

Figure 6

A comparison of the present experimental ${}^{100}\mathrm{Mo}(n,2n){}^{99}\mathrm{Mo}$ reaction cross sections with the literature data [13, 14, 15, 16, 17, 18, 19, 20, 21, 22], the evaluated data [24, 25, 26, 27], alice-2017 [29], and the theoretical values using optimized parameters in talys-1.9 [28].

Figure 7

A comparison of the experimental ${}^{100}\mathrm{Mo}(n,2n){}^{99}\mathrm{Mo}$ reaction cross sections with the theoretical values using CN and CN+PE modes in talys-1.9 [28].