56Fe Nuclei Research Articles

Cross Sections for Coherent Elastic and Inelastic Neutrino-Nucleus Scattering

The prospects of extracting new physics signals in coherent elastic neutrino–nucleus scattering (CEνNS) processes are limited by the precision with which the underlying nuclear structure physics, embedded in the weak nuclear form factor, is known. We present calculations of charge and weak nuclear form factors and CEνNS cross sections on 12C, 16O, 40Ar, 56Fe and 208Pb nuclei. We obtain the proton and neutron densities, and charge and weak form factors by solving Hartree–Fock (HF) equations with a Skyrme (SkE2) nuclear potential. We validate our approach by comparing 208Pb and 40Ar charge form factor predictions with available elastic electron scattering data. Since CEνNS experiments at stopped-pion sources are also well suited to measure inelastic charged–current and neutral–current neutrino–nucleus cross sections, we also present calculations for these processes, incorporating a continuum Random Phase Approximation (CRPA) description on top of the HF–SkE2 picture of the nucleus. Providing both coherent as well as inelastic cross sections in a consistent framework, we aim at obtaining a reliable and detailed comparison of the strength of these processes in the energy region below 100 MeV. Furthermore, we attempt to gauge the level of theoretical uncertainty pertaining to the description of the 40Ar form factor and CEνNS cross sections by comparing relative differences between recent microscopic nuclear theory and widely-used phenomenological form factor predictions. Future precision measurements of CEνNS will potentially help in constraining these nuclear structure details that will in turn improve prospects of extracting new physics.

The energy calibration system for CANDLES using (n,[formula omitted]) reaction

Calcium fluoride for the study of Neutrinos and Dark matters by Low-energy Spectrometer (CANDLES) searches for neutrino-less double-beta decay of 48Ca using a CaF2 scintillator array. A high Q-value of 48Ca at 4268 keV enabled us to achieve low background, however, at the same time it causes difficulties in calibrating the detector’s Q-value region because of the absence of a standard high-energy γ-ray source. Therefore, we have developed a novel calibration system based on γ-ray emission by neutron capture on 28Si, 56Fe, and 58Ni nuclei. In this paper, we report the development of the new calibration system as well as the results of energy calibration in CANDLES up to 9 MeV.

Theoretical cross-sectional calculation of some structural fusion material on (n, α)-induced reactions

27Al, 51V, 52Cr, 55Mn, 56Fe and 58Ni nuclei are some structural fusion substances. The neutron incident energy around 14–15 MeV is adequate to excite the nucleus for the reactions such as (n, p), (n, d), (n, 2n), (n, t), and (n, α). For fusion reactor technology, the reaction cross-sectional data have a critical importance in fusion reactors and development. Neutron irradiation produces considerable modifications in the mechanical and physical properties of each of the structural fusion material systems raising feasibility questions and design limitations. In this paper, for some structural fusion materials (n, α) reactions such as 52Cr(n, α)49Ti, 51V(n, α)48Si, 27Al(n, α)24Na, 58Ni(n, α)55Fe, 56Fe(n, α)53Cr and 55Mn(n, α)52V were done up to 40 MeV incident neutron energy. In the calculations, the equilibrium and pre-equilibrium impacts have been used. Calculations have been carried out with TALYS 1.9 and EMPIRE 3.2 (Malta) nuclear model codes. Results from performed calculations have been compared with the experimental nuclear reaction data, ENDF/B-VII.b4, JENDL-4.0 and JEFF-3.2 evaluated data.

The Real and Imaginary Volume Integrals in Spherical-Statistical Optical Potential of Neutron scattering from 56Fe nuclei

A spherical-statistical optical model (SOM) has been used to calculate and evaluate the neutron interaction with medium nuclei (40 ). Empirical formulae of the optical potentials parameters are predicted with minimize accuracy compared with experimental bench work data. With these optical formulae an evaluation of the shape and compound elastic scattering cross-section of interaction neutrons with 56 Fe nuclei at different energy range (1-20) MeV has been calculated and compared with experimental results. Also, volume integrals for real and imaginary potential energies have been evaluated and matched with the standard ABAREX code. Good agreements with have been achieved with the available experimental data.

Study of Inelastic A(p, p′)X Reaction with Nuclei at 1 GeV

The secondary-proton polarization and differential cross sections for the (p, p') inelastic reaction on 28Si and 56Fe nuclei at the initial proton energy of 1 GeV were measured over a wide range of the scattered-proton momenta at a laboratory angle of Θ = 21◦. Scattered protons were detected by means of a magnetic spectrometer equipped with a polarimeter based on multiwire proportional chambers and a carbon analyzer. A structure in the polarization and cross section data, which is probably related to quasielastic scattering off nucleon correlations in the 28Si and 56Fe nuclei, was observed as earlier in the analogous data for 12C and 40Ca nuclei. Momentum intervals within which cross-section ratios for nuclei did not depend on the scattered-proton momentum were found.

MANIFESTATION OF NUCLEAR CLUSTERIZATION IN COULOMB SUMS

The new experimental Coulomb sums values of 6Li and 7Li nuclei have been obtained at momentum transfers range q = 0.750¸ 1.000 fm-1 and q = 0.750¸ 1.125 fm-1, respectively, extending significantly the earlier reported momentum transfers range of Coulomb sums for these nuclei. The dependence of the 6Li and 7Li Coulomb sums on the momentum transferred is shown to differ substantially from same dependences for all the other investigated nuclei. It is suggested that the observed feature of the 6Li and 7Li Coulomb sums is related to a strong clusterization of these nuclei. The parameter qp corresponding to the value of the momentum transferred, at which the Coulomb sum ceases to grow and remains constant for larger momentum transfers, is introduced. The values of the parameter qp for the lithium isotopes nuclei were obtained (qp(7Li) = 1.20 ± 0.10fm-1 and qp(7Li) = 1.35 ± 0.10 fm-1), which are much lower than qp of 4He, 12C, 40Ca, 48Ca and 56Fe nuclei (qp » 2 fm-1). The graph represented the qp values of the nuclei as a function of the isolation parameter x, which characterizing the degree of nuclear clusterization, is constructed. The obtained graph shows the explicit proportionality of the qp dependence from the parameter x and predicts the qp value for the Coulomb sum of the 9Be nucleus not yet measured.

A new treatment of nonlocality in scattering process

Nonlocality in the scattering potential leads to an integro-differential equation. In this equation nonlocality enters through an integral over the nonlocal potential kernel. The resulting Schrödinger equation is usually handled by approximating r,-dependence of the nonlocal kernel. The present work proposes a novel method to solve the integro-differential equation. The method, using the mean value theorem of integral calculus, converts the nonhomogeneous term to a homogeneous term. The effective local potential in this equation turns out to be energy independent, but has relative angular momentum dependence. This method is accurate and valid for any form of nonlocality. As illustrative examples, the total and differential cross sections for neutron scattering off 12C, 56Fe and 100Mo nuclei are calculated with this method in the low energy region (up to 10 MeV) and are found to be in reasonable accord with the experiments.

A comprehensive analysis of elastic scattering of 14N projectile on 7Li, 9Be, 11B, 12C, 16O, 26Mg, 28Si, 40Ca, 56Fe, 59Co, 60,62Ni, 70,74Ge, 90Zr, 112Cd, 118Sn, 159Tb and 197Au at various incident energies

Elastic scattering data of 14N projectile on 7Li, 9Be, 11B, 12C, 16O, 26Mg, 28Si, 40Ca, 56Fe, 59Co, 60,62Ni, 70,74Ge, 90Zr, 112Cd, 118Sn, 159Tb and 197Au target nuclei are investigated at various incident energies. To obtain nuclear potential, two different approaches are applied. In first approach, the imaginary potential is assumed as the Woods-Saxon potential while the real potential is determined using the double folding model. In a second approach, both real and imaginary potentials are evaluated within the double folding model. The real and imaginary volume integrals and cross-sections of the systems investigated under different approaches are provided. Then, new equations which give the imaginary potential are obtained from the elastic scattering results. Finally, the effect of 10B + α and 13C + p cluster cases of 14N nucleus on the elastic scattering analysis is investigated by a simple approach.

Inelastic scattering of neutrinos on nuclei

The cross section of inelastic neutrino interaction with 56Fe and 208Pb nuclei is calculated. Investigation of these processes caused by neutral currents is essential for considering phenomena that occur during Supernova explosions and designing astrophysical neutrino detectors. The inelastic neutrino scattering cross section is calculated using the model independent approach, which is based on experimental data on nuclear structure. The values of the matrix elements of the considered reaction are determined from the characteristics of electromagnetic dipole М1 transitions in nuclei, obtained by means of nuclear resonance fluorescence.

Nuclear medium effects in structure functions of nucleon at moderate [formula omitted

Recent experiments performed on inclusive electron scattering from nuclear targets have measured the nucleon electromagnetic structure functions F1(x,Q2), F2(x,Q2) and FL(x,Q2) in 12C, 27Al, 56Fe and 64Cu nuclei. The measurements have been done in the energy region of 1 GeV2<W2<4 GeV2 and Q2 region of 0.5 GeV2<Q2<4.5 GeV2. We have calculated nuclear medium effects in these structure functions arising due to the Fermi motion, binding energy, nucleon correlations, mesonic contributions from pion and rho mesons and shadowing effects. The calculations are performed in a local density approximation using a relativistic nucleon spectral function which includes nucleon correlations. The numerical results are compared with the recent experimental data from JLab and also with some earlier experiments.

Study of Some Structural Fusion Materials for (n,2n) Reactions

Studies of (n,2n) reaction are especially important for neutron multiplication. The (n,2n) cross section is neutron multiplier reaction in fusion reactor design. 27Al, 51V, 52Cr, 55Mn, 56Fe and 58Ni nuclei are the some structural fusion materials. Therefore, (n,2n) reactions of the selected blanket materials can play a key role for multiplying neutrons in reactor environment. In this study, for some structural fusion materials (n,2n) reactions such as 27Al(n,2n)26Al, 51V(n,2n)50V, 52Cr(n,2n)51Cr, 55Mn(n,2n)54Mn, 56Fe(n,2n)55Fe and 58Ni(n,2n)57Ni have been carried out up to 30 MeV incident neutron energy. In the calculations, the pre-equilibrium and equilibrium effects have been used. The calculated results have been compared with the experimental data as well as with evaluated data files.

Corrected analytical solution of the generalized Woods–Saxon potential for arbitrary states

The bound state solution of the radial Schrödinger equation with the generalized Woods–Saxon potential is carefully examined using the Pekeris approximation for arbitrary states. The energy eigenvalues and the corresponding eigenfunctions are analytically obtained for different n and quantum numbers. The closed forms obtained are applied to calculate the single particle energy levels of a neutron orbiting around 56Fe nucleus in order to check the consistency between the analytical and the Gamow code results. The analytical results are in good agreement with the results obtained using Gamow code for .

Absolute stability window and upper bound on the magnetic field strength in a strongly magnetized strange quark star

Magnetized strange quark stars, composed of strange quark matter (SQM) and self-bound by strong interactions, can be formed if the energy per baryon of magnetized SQM is less than that of the most stable 56Fe nucleus under the zero external pressure and temperature. Utilizing the MIT bag model description of magnetized SQM under charge neutrality and beta equilibrium conditions, the corresponding absolute stability window in the parameter space of the theory is determined. It is shown that there exists the maximum magnetic field strength allowed by the condition of absolute stability of magnetized SQM. The value of this field, H ~ 3 × 1018 G , represents the upper bound on the magnetic field strength which can be reached in a strongly magnetized strange quark star.

Structure of dipole resonances in iron isotopes 54Fe and 56Fe

The probability distributions of photoexcitations in 54Fe and 56Fe nuclei were obtained within the particle-core coupling version of the multiparticle shell model by using the spectroscopy of direct pickup reactions.

Nuclear diffraction dissociation of 16O, 22Ne, 28Si, 32S, 56Fe at 1–3.7 A GeV in nuclear emulsion

In this paper, we discuss various aspects of the nuclear diffraction dissociation interactions of 16O, 22Ne, 28Si, 32S, 56Fe nuclei accelerated at the Dubna–JINR Synchrophasotron and Nuclotron in the energy range 1–3.7 A GeV. We use criteria which separate electromagnetic dissociation events among the nuclear collisions. We describe their topology and study their characteristic parameters, relative rates of nuclear fragmentation, average multiplicities and the angular distributions of fragments as a function of the energy and of the nature of the primary nuclei. Nuclear emulsions were used for this purpose, which allowed the detection of all projectile and target fragments.

Investigation of the Appropriate Partial Level Density Formula for Pre-Equilibrium Nuclear Exciton Model

Ericson formula represents the first formula, which was suggested to describe the partial level density (PLD) formula in pre-equilibrium region of the nuclear reactions. Then a number of corrections were added to this formula in order to make it more suitable to physical meaning. In this paper, there are two aims to be done: the first aim is to study the correspondence between one and two-components formulae in Ericson, Pauli, and pairing corrections; the second aim is to compare and study the results of Comprehensive formula, which contents with all corrections, with Ericson, Pauli, and pairing formulae. The Comprehensive formula was suggested to simulate the reality. To achieve these aims the 56Fe and 90Zr nuclei were chosen and the results showed that the difference between one and two-components formulae was too small which can be neglected. Furthermore, the results strongly recommended that for cross section calculations of the nuclear reaction, one must use Comprehensive formula rather than Pauli formula.

Study of the EMC Effect for &amp;lt;sup&amp;gt;27&amp;lt;/sup&amp;gt;Al, &amp;lt;sup&amp;gt;56&amp;lt;/sup&amp;gt;Fe, &amp;lt;sup&amp;gt;63&amp;lt;/sup&amp;gt;Cu, and &amp;lt;sup&amp;gt;107&amp;lt;/sup&amp;gt;Ag Nuclei

In this paper the EMC effect for 27Al, 56Fe, 63Cu, and 107Ag nuclei are investigated with oscillator model. In this model has been assumed that nucleons in each level are affected by different mean field, so we use parameter having relation with radius of each level. Therefore; this assumption causes that extracted data for average binding energy =-22.48MeV, =-23.79MeV, =-29.56MeV, and =-31.25MeVare considered for 27Al, 56Fe, 63Cu, and 107Ag nuclei, respectively. Achieving results have agreement with experimental data.

Gamow-Teller resonance in hot nuclei and astrophysical applications

A formalism based on thermo field dynamics is described. It allows the effect of the temperature on the strength distribution of charge-exchange transitions in hot nuclei to be taken into account. Numerical calculations with the pair correlations in the BCS approximation and the schematic στ interaction are carried out for Gamow-Teller transitions in the 56Fe nucleus. The electron capture and β− decay rates are calculated for this nucleus at temperatures and densities corresponding to the advanced stage of the evolution of massive stars.

Measurement of a direct alpha-particle flow in collisions of 56Fe nuclei with photoemulsion nuclei at a momentum of 2.5 GeV/c per nucleon

Measurement of a direct alpha-particle flow in collisions of 56Fe nuclei with photoemulsion nuclei at a momentum of 2.5 GeV/c per nucleon

Measurement of the elliptic flux of Z ⩾ 2 charged particles in collisions of relativistic nuclei with photoemulsion nuclei

The azimuthal asymmetry is measured for the emission of Z ≥ 2 particles from the interaction of 22Ne, 24Mg, 32S, 56Fe, 197Au, and 207Pb nuclei with photoemulsion nuclei that is induced by semicentral collisions characterized by projectile energies in the range Epr = 1.88–200 GeV per nucleon and by impact-parameter (b) values in the range 0.12 ≤ b/bmax ≤ 0.70. The results of these measurements are compared with the results of similar measurements for protons. It is found that, at a low energy of Epr ≈ 2 GeV per nucleon, the ratio of the azimuthal-anisotropy coefficients v2 for Z ≥ 2 particles and protons is 6 ± 2, but that, for energies in the region Epr ≥ 4 GeV per nucleon, the coefficients in question agree with each other. This may suggest that, at low energies, Z ≥ 2 particles are predominantly formed at an early stage of the development of a collective flow. For Epr ≥ 4 GeV per nucleon, these particles are presumably formed at the stage of nuclear-matter expansion. Other possible explanations for the results of the observation of an elliptic flux of Z ≥ 2 particles are discussed.