Calculation Of Reaction Cross Sections Research Articles

Vortex photon induced nuclear reaction: Mechanism, model, and application to the studies of giant resonance and astrophysical reaction rate

The vortex photon beam induced nuclear reaction is studied. The interaction formalism of nuclei with vortex photons is developed and incorporated into the statistical reaction model to calculate reaction cross-sections. For 138 nuclei of high nuclear astrophysics and structure interest, the cross-sections of γ-ray emission and neutron production from the decay of the giant resonances (GR) populated by vortex photons, e.g., (γvo,γemit) and (γvo,nprod.), are computed. It is shown that for the (γvo,γemit) and (γvo,nprod.) cross-sections, the GR contribution of an individual L is either enhanced or suppressed depending on the parameters of vortex γ-rays, and the contribution from the GR of a specific L can be identified and deduced. To this end, a novel method to exclusively determine the γ-strength function (γSF) for the GR of a specific L is proposed considering the (γvo,γemit) and (γvo,nprod.) measurements, and the feasibility studies demonstrate that the γSF for the giant quadrupole resonance can be extracted. Furthermore, the astrophysical reaction rates of the vortex photon induced reactions in p-process are investigated. It is indicated that photo-nuclear reactions induced by vortex photons will bring new insights in nuclear physics and astrophysics research.

Studying optimum values of statistical model ingredients for (,) and (,) reactions

In order to further develop nuclear models/functions, it is important to test various models and functions included in cross-section calculations based on different reaction types, energy ranges, and masses. In this study, the dependence of nuclear ingredients such as level density, -nucleus optical model and γ-ray strength function on the cross-section were illustrated by making systematic calculations in the statistical model window. Reaction cross-section calculations were systematically performed for (α,γ) and (γ,α) reactions, which hold significant importance in astrophysics, on various target nuclei. Theoretical model calculations were compared with experimental data. For each set of experimental and calculated cross sections, the average deviation factor values were determined. The best-fit models and functions for all incoming alpha and gamma energies and for all target nuclei were identified.

Comparative study for the elastic scattering of the isobar nuclei 6Li and 6He on 64Zn using different nuclear potentials

The available experimental data for the elastic scattering of the isobar nuclei 6Li and 6He on [Formula: see text]Zn have been reanalyzed in the available energy range using the optical model, double folding (DF) (Sao Paulo), and crystal model (CM). Double-folding (DF) and crystal model (CM) have been used to investigate the experimental data as a real part of the optical potential, while the imaginary part was taken in Woods–Saxon (WS) shape. One value of the real part of the optical potential has been applied to the two systems under consideration. The distance of the closest approach of the 6Li (6He) + [Formula: see text]Zn systems has been extracted from the available experimental data using different methods. The extracted potential from the 6Li and 6He elastically scattered by [Formula: see text]Zn data could be used as the basis for the creation of a simple global optical potential for 6Li and 6He. The extracted normalization factor ([Formula: see text]) was equal to the unity during the fitting process avoiding its unfortunate value (in the range 0.5–0.7) exists in the literature. It was observed that interaction distances vary slowly with the energy of the projectile and strongly depend on the projectile properties. The halo properties of 6He have a significant effect on the calculated reaction cross-sections. Different methods have been applied to 6He and 6Li elastically scattered by [Formula: see text]Zn, where fair agreement between them has been observed.

Generation of fusion and fusion-evaporation reaction cross-sections by two-step machine learning methods

In order to obtain cross-sections of heavy-ion fusion and fusion-evaporation reactions, artificial neural networks, cubist, random forest, support vector regression, extreme gradient boosting, and multiple linear regression machine learning approaches were used separately in this study. The outcomes from these different methods that are obtained from the training carried out with the existing experimental data in the literature were compared. Furthermore, it has been observed that a two-step process yielded better results for determining the heavy-ion reaction cross-sections, after first estimating which approach would be better for which reaction. In this manner, the method for which the cross-section needs to be calculated is determined by the machine learning classification application, and predictions can be made using the machine learning regression application with the determined method. It has been concluded that the obtained results are in harmony with the experimental data and that the methods can be used safely. The obtained results are published on a web page that allows for online calculation of heavy-ion fusion and fusion-evaporation reaction cross-sections.

Investigation of the 121Sb(α,γ)125I reaction cross-section calculations at astrophysical energies

Investigation of the 121Sb(α,γ)125I reaction cross-section calculations at astrophysical energies

Excitation function of neutron induced reaction on isotopes of cadmium (106Cd, 108Cd &110Cd) in the energy range of 13–15 MeV

This study focuses on the theoretical calculations of neutron-induced reaction cross-sections on several stable isotopes of cadmium within the energy range of 13–15 MeV. The nuclei produced in this process include 105Cd, 106Ag, 107Cd, 109Cd, and 110Ag. To calculate the reaction cross-sections for specific reactions such as 106Cd (n, 2n) 105Cd, 106Cd (n, p) 106Ag, 108Cd (n, 2n) 107Cd, 110Cd (n, 2n) 109Cd, and 110Cd (n, p) 110Ag, we employed the Alice 91-based computer code. The calculated results were then compared and tabulated alongside experimental data obtained from the International Atomic Energy Agency (IAEA) data source, EXFOR library. Additionally, we plotted the reaction cross-sections against neutron energy (excitation function) for each reaction channel. Our findings demonstrate a strong agreement between the calculated and experimental data within the specified neutron energy range. Furthermore, we introduced several statistical parameters to assess the fitting quality between the theoretically calculated and experimentally measured reaction cross-section values.

Advances on clusters and correlations in nuclear structure and reactions

Recent advances obtained in the last few years by the Theoretical Nuclear Physics group in Padova with various collaborators on alpha-cluster models and on nuclear correlations in stable and unstable light nuclei are reviewed in this contribution. The algebraic cluster model assumes triangular and tetrahedral arrangement of α particles for 12C and 16O respectively. The description of the low-lying states achieved in this model, that is a consequence of the requirement of discrete symmetries, is extremely good. We have made several calculations of α-transfer form factors and reaction cross-sections obtaining a good agreement with available data, thus corroborating the main hypotheses of the model [1]. We have speculated about smoking-gun nuclear fluorescence experiment that might shed light on the exact spatial arrangement of alpha particles in 12C [2]. We will also talk about the successful predictions on the positioning of 29F on the southern shore of the island of inversion [3] and on recent calculations on its halo character and dipole response [4, 5]. Extension of these calculations to 31F [6], pointing out the presence of a halo, are also discussed.

Investigation of charged-particle induced reactions on 27Al up to 100 MeV leading to the formation of 22Na and 24Na

Abstract Studies using theoretical models are of great importance for understanding of reaction process and its nature. In this study, nuclear level density model calculations of the cross sections of 27Al are investigated by using TALYS 1.96 computer code. The cross section calculations of 27Al(α,x)22Na, 27Al(α,x)24Na, 27Al(3He,x)22Na, 27Al(3He,x)24Na, 27Al(p,x)22Na and 27Al(p,x)24Na reactions were carried out for incident particle energy up to 100 MeV. In these calculations, four nuclear level density models, namely constant temperature model (CTM), back-shifted Fermi gas model (BSFGM), generalized superfluid model (GSM) and recently proposed semi-classical Fermi gas model (CSCFGM) are used. This model is developed using the simplest model BSFGM. The most obvious difference between CSCFGM and other models is the inclusion of the collective effects in the base of the formulation. The predicted results are discussed and compared with each other and the available experimental data taken from EXFOR library. In order to better evaluate the model results, chi-squared values are calculated and compared with each other for all analyzed reactions. According to the chi-squared results, CSCFGM gives closer predictions to the experimental data compared with the other models in 4 of the 6 analyzed reactions. Therefore, in this study, it is presented that this model can be reliably used in the reaction cross section calculations.

Vibrational, non-adiabatic and isotopic effects in the dynamics of the H2 + H2 + → H3 + + H reaction: application to plasma modelling

The title reaction is studied using a quasi-classical trajectory method for collision energies between 0.1 meV and 10 eV, considering the vibrational excitation of H 2 + reactant. A new potential energy surface is developed based on a Neural Network many body correction of a triatomics-in-molecules potential, which significantly improves the accuracy of the potential up to energies of 17 eV, higher than in other previous fits. The effect of the fit accuracy and the non-adiabatic transitions on the dynamics are analysed in detail. The reaction cross section for collision energies above 1 eV increases significantly with the increasing of the vibrational excitation of H 2 + ( v ′ ), for values up to v ′ =6. The total reaction cross section (including the double fragmentation channel) obtained for v ′ =6 matches the new experimental results obtained by Savic, Schlemmer and Gerlich [Chem. Phys. Chem. 21 (13), 1429.1435 (2020). doi:10.1002/cphc.v21.13]. The differences among several experimental setups, for collision energies above 1 eV, showing cross sections scattered/dispersed over a rather wide interval, can be explained by the differences in the vibrational excitations obtained in the formation of H 2 + reactants. On the contrary, for collision energies below 1 eV, the cross section is determined by the long range behaviour of the potential and do not depend strongly on the vibrational state of H 2 + . In addition in this study, the calculated reaction cross sections are used in a plasma model and compared with previous results. We conclude that the efficiency of the formation of H 3 + in the plasma is affected by the potential energy surface used.

Effect of deformation dependence and mirror nucleus corrections energy on multinucleon transfer reaction cross sections

Multinucleon transfer reactions are currently a powerful way to synthesize neutron-rich nuclei. To explore the effect of nucleus deformation and mirror nucleus shell correction energy in the nucleus mass model on the calculation of multinucleon transfer reaction cross sections in the dinuclear system (DNS) model, three macroscopic microscopic mass models are selected and the transfer reaction cross sections are calculated for 136Xe+208Pb and 64Ni+238U by improved DNS model+GEMINI++, respectively. The mirror nucleus shell correction energy does not improve the accuracy of the cross section of the transfer reaction. The introduction of a different dependence of the Coulomb and surface energy on the deformation can improve the calculation of the transfer reaction cross section when the projectile and target nuclei are deformed nuclei.

(d, 3n) Reaction cross-section calculation of some reactor materials

Nuclear reactions with charged particles have applications in many fields such as radioisotope production, industrial applications, astrophysics, etc. Therefore, examining the excitation functions performed and obtained by the activation technique is also important for understanding the nature of nuclear reactions. Also, it is especially necessary to study these reactions to estimate the effects of radiation damage on the fusion structural materials used in the construction of the first walls and core of the reactor. In this study, cross-section data have been calculated theoretically to 45Sc (d, 3n)44Ti, 63Cu (d, 3n)62Zn, 89Y (d, 3n)88Zr, and 100Mo (d, 3n)99Tc reactions in the range of 1–50 MeV energy via ALICE/ASH, TALYS 1.95 and Empire 3.2.2 nuclear reaction codes. Optical Model Parameters (OMP) calculation for deuteron-induced reaction results has been performed via TALYS 1.95 code and the calculated cross-section values are reproduced well. Also, empirically developed (d, 3n) cross section formula (Kavun, 2020) calculations have been performed at 20 MeV energy. Finally, experimental EXFOR data was compared with all results and were found to be compatible with each other.

Isomeric cross sections of the (n, α) reactions on the 90Zr, 93Nb and 92Mo isotopes measured for 13.73 MeV–14.77 MeV and estimated for 10 MeV–20 MeV neutron energies

Isomeric cross sections for the 90Zr(n, α)87Srm, 93Nb(n, α)90Ym and 92Mo(n, α)89Zrm reactions were measured at five neutron energies over the range 13.73 MeV–14.77 MeV using the activation technique in combination with high resolution γ-ray spectrometry. In the present work, the cross sections are measured for the 90Zr(n, α)87Srm and 93Nb(n, α)90Ym reactions are referenced to the 27Al(n, α)24Na standard reaction cross section whereas those measured for 92Mo(n, α)89Zrm reaction are referenced to the 56Fe(n, p)56Mn standard reaction cross section. The cross sections for these reactions were also theoretically estimated using the EMPIRE-3.2 and TALYS 1.8 codes over the neutrons energy range of 10 MeV–20 MeV and matched with the experimental cross sections by making a proper choice of the model parameters. A minimum eight different sets of these statistical model calculations were performed by using the consistent sets of model parameters along with the pre-equilibrium mechanism in addition to the direct-reaction and the statistical Hauser–Feshbach (HF) compound nucleus ones. The measured cross sections for these three reactions increase with the increase in neutron energy from 13.73 MeV to 14.77 MeV. As the proton number increased by one when we go from zirconium to niobium or from niobium to molybdenum, the probability of alpha particle emission also increases at each corresponding neutron energy. The present results indicate that the measured cross section at each neutron energy for the 92Mo(n, α)89Zrm reaction is found to be the highest as compared to the other two reactions whereas, for the 90Zr(n, α)87Srm reaction, the measured cross section is found to be the lowest as compared to the other two reactions studied. The results obtained from the present measurement are found to be in good agreement with the calculated reaction cross section based on theoretical models and also with the work reported by earlier authors.

Investigation of neutron-induced reaction cross section calculations for the fusion reactor structural materials using artificial neural networks

Using artificial neural networks for an estimation of the nuclear reaction cross section data is discussed. Approximately rate of the fitting criteria is determined by the calculated experimental data obtained from using Variable Learning Rate Backpropagation (traingdx) algorithm in artificial neural networks. This method has been applied to obtain the cross section for 14–15 MeV neutron-induced (n,α) and (n,p) reactions in the fusion reactor structural materials. In comparison to the reaction cross section calculation by experimental cross sections reported in EXFOR, TALYS 1.9 and EMPIRE 3.2, the proposed method has better prediction ability when the target output has a large variation between the experimental and the calculated data. This study is substantial for the new method validation development of the nuclear model approaches with the increased prediction power of the neutron-induced reactions for fusion reactor systems.

INVESTIGATION OF NEUTRON-INDUCED REACTION CROSS SECTIONS FOR SEVERAL NUCLEAR REACTOR STRUCTURAL MATERIALS

Selection of the appropriate materials as a structural components of nuclear reactor are of key importance to implement the highest efficiency and security. Zr, Fe, Cr, Sn and Nb are commonly used materials involved in structural alloy inside the reactor. The presented result of neutron-induced reaction cross section calculations for Cr50-52-53-54, Fe54-56-57, Nb93, Sn117-119-124, Zr90-91-92 have been computed using Constant Temperature Model, Back Shifted Fermi Gas Model, Generalised Super Fluid Model and Microscopic level densities presented in TALYS 1.9 nuclear code. The calculations have been repeated by changing the level density parameter a for each isotope and model to observe changes in the model assumption. The obtained results are compared with the experimental data taken from the literature.

Cross sections for the $$\left( {n, p} \right)$$ reaction of selenium isotopes within 10.5 to 19.81 MeV neutron energies

The cross sections of the selenium isotopes 76Se, 77Se, 78Se and 80Se within 10.5–19.81 MeV neutron energy range have been measured through neutron activation method along with off-line γ-ray spectrometry. The quasi-monoenergetic neutrons were produced from the 7Li $$\left( {p, n} \right)$$ reaction at 14UD BARC-TIFR Pelletron Accelerator Facility, Mumbai, India. The statistical codes TALYS-1.9 and EMPIRE-3.2.2 were applied for the theoretical calculation of reaction cross sections with different level density models from 2 to 22 MeV neutron energies. Besides this, the Se $$\left( {n, p} \right)$$ As reaction cross sections were also calculated from different systematic formulae within 14–15 MeV neutron energies. The measured data were compared with existing literature data available in the EXFOR database, evaluated data of ENDF/B-VIII.0, JENDL-4.0 and TENDL-2019 libraries and with theoretical outcomes through TALYS-1.9 and EMPIRE-3.2.2 codes. The uncertainties in existing cross sections were calculated through the method of covariance analysis by including partial uncertainties and correlation among the different attributes. The $$\left( {n, p} \right)$$ reaction cross sections of selenium isotopes at higher neutron energies first time measured in the present work can be added as new data in the nuclear data library.

Cross section calculations for neutrino-nucleus reactions at low and intermediate energies.

Inelastic neutrino-nucleus reaction cross sections are studied focusing on the neutral current processes. Particularly, we investigate the angular and initial neutrino-energy dependence of the differential and integrated cross sections for low and intermediate energies of the incoming neutrino (or antineutrino). Contributions coming from both, the vector and axial-vector components of the corresponding hadronic currents have been included. The initial and final state nuclear wave-functions have been calculated in the context of the Quasi-particle Random Phase Approximation (QRPA) tested on the reproducibility of the low-lying energy spectrum (up to about 5 MeV) of the studied nuclei. The results presented here refer to the nuclear isotopes 16O and 98Mo. As it is well known, O plays a significant role in supernova evolution phenomena and Mo is used as a target in the MOON neutrino experiment at Japan.

Investigation of nuclear reaction mechanisms of Nickel isotopes at various energies induced by alpha particles

The excitation functions of 58Ni (α, n + 2p + α) 55Fe, 58Ni (α, n + 3p) 58Co, 58 Ni (α, n + p) 60Cu, 58Ni (α, n + p+α) 56Co, 58Ni (α, p) 61Cu, 58Ni (α, p+α) 57Co and58Ni (α, 2n+p + α )55Co reactions were studied for particle energies up to 70 MeV. The aim of this study is to investigate the reaction mechanisms of 58Ni isotopes induced by alpha particle using computer code COMPLET and EXFOR database. Calculated results of the excitation functions are discussed and compared with the experimental data taken from database. Comparisons of theoretical nuclear reaction cross-section calculations give remarkable agreements with the experimental data taken from EXFOR database.

(p, g), (n, g) ve (a,g) Reaction Cross Section Calculations and Optimization for the Isotopes of 58,60,61,62,63,64Ni using Artificial Neural Networks

Bu çalışmada; nükleer reaksiyon tesir kesiti verilerinin hesaplanması için yapay sinir ağlarının kullanımı incelenmiştir. Uygulama kriterleri yaklaştırma oranı, deneysel veriler, değerlendirilmiş veriler ve teorik nükleer reaksiyon modelleri ile gerçekleştirilen hesaplama değerleri kullanılarak belirlenmiştir. 58,60,61,62,63,64Ni izotopları için (n, g), (p, g) ve (a, g) reaksiyon tesir kesitleri yapay sinir ağları kullanılarak hesaplanmıştır. Sonuçlar, bu yeni tekniğin bazı nükleer reaksiyonların hesaplanmasındaki etkinliğini ve uygulanabilirliğini göstermektedir.Gelişen teknolojiye ve sanayileşmeye bağlı olarak enerjiye duyulan ihtiyacın giderilmesi yönünde nükleer enerjiye ve nükleer enerji reaktörlerine yönelim olmuştur. Nükleer enerjiye olan bu yönelim ve ilgi, nükleer teknolojisinde ve fisyon reaksiyonu temelinde yeni reaktör sistemlerinin tasarlanmasına yol açmıştır

Theoretical photoneutron cross-section calculations on Osmium isotopes by Talys and Empire codes

In this study, the level density parameter and the gamma ray strength function effects on photoneutron reaction cross-section calculations for Osmium isotopes were investigated by employing available level density models and gamma ray strength functions within Talys v1.8 and Empire v3.1 nuclear codes. A relative variance analysis was done to determine the best gamma ray strength function. Then, the effect of level density models for the photoneutron reactions was investigated by using the best gamma ray strength function. The results were compared with each other and also with the experimental data taken from the literature.

Study on cross section calculations for (n,p) nuclear reactions of cadmium isotopes

A theoretical study of the cross sections of (n,p)reactions on Cadmium isotopes has been performed using the Hauser-Feshbach model, Weisskopf-Ewing model, Exciton model, Two-component exciton model and Geometry dependent hybrid model for the incident energies from the reaction threshold to 20MeV. Furthermore, the empirical formulae based on the different systematics at the energies near 14.5MeV were used for calculating the (n,p)nuclear cross sections. Finally, the results of the present paper are discussed and compared with the experimental cross sections and TENDL-2017 data found in the literature.