Simulation study of the proton-induced reaction cross sections for the production of 18F and 66–68Ga radioisotopes

A new empirical formula for calculation of (n,3n) cross sections of heavy mass nuclei in the energy region 22-27.5 MeV

In this paper we want to study (n,3n) reactions using an empirical formula derived on the basis of the statistical model considering reaction Q-value dependence. This formula was obtained by taking into account the exponential dependence on asymmetry parameter (N-Z)/A for neutron-induced reactions in Levkovskii's empirical formula. In addition, the present formula depends also on incident energy En, reaction Q-value and symmetry term (N-Z)2/A. Herein, a new analysis of experimental data of (n,3n) reactions in the energy region 22-27.5 MeV was carried out for quick estimation of cross sections of the heavy mass isotopes of odd Z-even N nuclides in the region of A = 151 to 209. We observed a good agreement of the experimental cross section data with the calculations performed using the present empirical formula.

Activation cross sections for reactions induced by 14 MeV neutrons on natural titanium

Cross sections for the neutrons around 14 MeV interaction with natural titanium were precisely measured by neutron activation and off-line measurement technique. The fast neutrons were produced by ³H(d,n)⁴He reaction and the neutron energy was obtained by using the cross section ratio method of ⁹⁰Zr(n,2n)⁸⁹Zr to ⁹³Nb(n,2n)^92mNb reactions. Experimental cross sections have been acquired for ^natTi(n,x)⁴⁶Sc, ^natTi(n,x)⁴⁷Sc, ⁵⁰Ti(n,x)⁴⁷Ca and ⁴⁸Ti(n,x)⁴⁸Sc reactions. The measured cross section data are compared with the experimental data available in the previous literature and evaluated nuclear data from the ENDF/B-VIII.0, JEFF-3.3, JENDL-5, BROND-3.1, CENDL-3.2 and FENDL-3.2b libraries. Furthermore, excitation functions for these reactions were calculated by using the theoretical model based on Talys-1.96 code with default and adjusted parameters. Within experimental error, evaluated nuclear data are mostly consistent with experimental data. The excitation function with adjusted parameters can roughly reproduce the experimental data.

Effects of some level density models and γ-ray strength functions on production cross-section calculations of 16,18O and 24,26Mg radioisotopes

Oxygen and magnesium isotopes can be used in nuclear reactor materials as cooling, shielding, coating, electronics etc. They can also occur through nuclear reactions during the reactor operation. The exposure of high energy gamma can change the material and its properties, and hence its objective of selection may not remain satisfied. Thus, it is required to study the cross section of different reactions on nuclear reactor materials to understand their sustainability for the properties, for which they are chosen. In the scope of this study, theoretically, different level density model calculations and γ-ray strength functions have been performed for (γ, p) reaction for 16,18O and 24,26Mg nuclei using TALYS 1.9 and EMPI˙RE 3.2.2 codes. Also, semi empirical (γ, p) formula by Tel et al., have been calculated and compared with all results. The effect of different level density models defined in these codes on gamma strength has been studied. Finally, the consistency of these obtained data with EXFOR data have been investigated.

Evaluation of nuclear reaction cross sections for optimization of production of the non-standard positron emitting radionuclide 90Nb using proton induced reactions on Zr target

Niobium-90 radionuclide is one of the promising candidates for the positron emission tomography (PET) technique. In this study, ⁹⁰Nb excitation functions via ⁹⁰Zr(p,n) and ^natZr(p,xn) reactions were computed using the TALYS-1.95 code based on phenomenological and microscopic level density models. The MCNPX simulation code was used for each case. Moreover, the target thicknesses were obtained using the SRIM-2013 code and the theoretical and simulation-based production yields of the ⁹⁰Nb were evaluated. The experimental production yield amounts of about 72.68 and 126.7 (both in MBq/μAh) for ⁹⁰Zr(p,n) and ^natZr(p,xn) reactions in the corresponding optimal energy windows were attained by our experiments respectively.

Estimations of giant dipole resonance parameters using artificial neural network

In this study; Giant Dipole Resonance (GDR) parameters of the spherical nucleus have been estimated by using artificial neural network (ANN) algorithms. The ANN training has been carried out with the Levenberg-Marquardt feed-forward algorithm in order to provide fast convergence and stability in ANN training and experimental data, taken from Reference Input Parameter Library (RIPL). R values of the system have been found as 0.99636, 0.94649, and 0.98318 for resonance energy, full width half maximum, and resonance cross-section, respectively. Obtained results have been compared with the GDR parameters which are taken from the literature. To validate our findings, newly acquired GDR parameters were then replaced with the existing GDR parameters in the TALYS 1.95 code and ^142-146Nd(γ,n)^141-145Nd reaction cross-sections have been calculated and compared with the experimental data taken from the literature. As a result of the study, it has been shown that ANN algorithms can be used to calculate the GDR parameters in the absence of the experimental data.

Excitation functions of the Zn(p,xn)Ga reactions

The excitation functions for ^{64,66,67,68,70}Zn(p,n)^{64,66,67,68,70}Ga and ^{64,66,67,68,70}Zn(p,2n)^{63,65,66,67,69}Ga have been calculated for incident proton energies from threshold values to 30 MeV using the statistical model code TALYS-1.6. The (p,n) and (p,2n) cross sections have been calculated using both phenomenological Koning and Delaroche (KD) and semimicroscopic Jeukenne-Lejeune-Mahaux-Bruyeres (JLMB) optical model potentials. The phenomenological back-shifted Fermi gas model (BFM) and microscopic Hartree-Fock (HF) approaches for calculation of level densities have been compared in the present work. The pre-equilibrium process has been treated using exciton model. The sensitivity of cross section data to different models of optical model potential and level density have been investigated. It is found that the (p,n) and (p,2n) cross section calculations with semimicroscopic JLMB optical model potential and microscopic HF level density show agreement with the data. The (p,n) and (p,2n) cross section calculations have been compared with corresponding cross sections from nuclear data library, TENDL-2019. The (p,xn) cross sections obtained will be useful in several applications, particularly, for optimization of production routes for Ga isotopes.

Calculation of 89Y(p,x)86,88,89gZr, 86g,87g,88gY, 85gSr, and 84Rb reaction cross sections based on level density

Excitation functions based on level density were calculated for proton-induced on yttrium-89 using the TALYS-1.8 code. Hence, production cross-section of the ⁸⁹Y(p,x)^86,88,89gZr, ^86g,87g,88gY, ^85gSr, and ^84gRb were computed up to 50 MeV. In this study, the constant temperature model alongside the Fermi Gas model (CGCM) was employed as a default model. For this reason, the a-parameter as an essential parameter in the Fermi Gas formula was modified to obtain the best result. Besides, the Back-shifted Fermi Gas Model (BSFGM) and the Generalized Superfluid Model (GSM) are presented to the deliberation. The outcomes of cross-sections were compared with the experimental data approaching regarding desired consequences.

A new study on pre-equilibrium and equilibrium effects of excitation functions of alpha-induced reactions on 51V, 55Mn and 59Co nuclei

In this article, the cross section simulations of ⁵¹V(α,n)⁵⁴Mn, ⁵⁵Mn(α,n)⁵⁸Co, ⁵⁵Mn(α,2n)⁵⁷Co, ⁵⁹Co(α,2n)⁶¹Cu and ⁵⁹Co(α,α2n)⁵⁷Co nuclear reactions were carried out using the pre-equilibrium and equilibrium models. TALYS 1.9 and ALICE/ASH codes for the above nuclear reactions were used to describe the formation of the reaction process. Besides, the contribution on the cross section calculations of initial exciton number for alpha-induced reactions at the pre-equilibrium emissions is discussed. The results of this paper are compared with the measured nuclear data found in the literature. It was found that the initial exciton number n₀  = 5 appears to give a good harmony to the measured values.