Light charged particle emission for p+Fe reactions

The energy spectra and double differential cross sections of nucleon and the light composite particle (d, t, ³He and α) emissions are studied based on the exciton model included the improved Iwamoto-Harada model. All cross sections of proton induced reactions, angular distributions and energy spectra are consistent calculated and analyzed for ^{54,56,57,58,nat}Fe at incident proton energies below 250 MeV by using nuclear theoretical models which integrate the optical model, the intra-nuclear cascade model, direct, pre-equilibrium and equilibrium reaction theories. Theoretical calculated results are compared with existing experimental data.     

Double differential cross sections of light charged particle emission in neutron induced reactions on Fe

The energy spectra and double differential cross sections of the light composite particle (deuteron, triton, helium and alpha-particle) emissions for n + ^54,56,57,58Fe reaction are studied by integrating the optical model, the intra-nuclear cascade model, direct reaction theories, equilibrium reaction theory and the exciton model which included the improved Iwamoto–Harada model. Theoretical calculated results are compared with existing experimental data.     

Double differential cross sections of n + Cu reactions

The energy spectra and double differential cross sections of neutron, proton, deuteron, triton, helium and alpha-particle emissions for n + ^63,65,nat.Cu reactions are calculated and analyzed at incident neutron energies below 200 MeV. The optical model, the intra-nuclear cascade model, direct reaction theories, the unified Hauser–Feshbach and exciton model which includes the improved Iwamoto–Harada model are used. Theoretically calculated results are compared with the existing experimental data.     

Calculation and analysis of n+Zr reactions in the En ⩽ 250 MeV energy range

All of reaction cross sections, angular distributions, energy spectra, γ-ray production cross sections, and the double differential cross section for neutron, proton, deuteron, triton, helium and alpha emission are calculated and analyzed for n+^{90,91,92,94,96,nat}Zr at incident neutron energies from 0.1 to 250 MeV. The optical model, intranuclear cascade model, the unified Hauser–Feshbach theory and the exciton model which included the improved Iwamoto–Harada model are used. Theoretical calculated results are compared with existing experimental data and other evaluated data from ENDF/B-VI.8, ENDF/B-VII.0 and JENDL-3.3. The optical model potential parameters are obtained according to the experimental data of total, nonelastic cross sections and elastic scattering angular distributions.     

Theoretical calculation and analysis of the p+Co reaction

All cross sections, elastic and inelastic scattering angular distributions, energy spectra, and double differential cross sections of neutron, proton, deuteron, triton, helium and alpha particle emission for the p+⁵⁹Co reaction have been calculated and analyzed at incident energies from threshold to 200 MeV. The optical model, the intra-nuclear cascade model, direct, pre-equilibrium and equilibrium reaction theories are used. It is found that the theoretical calculated results are in good agreement with experimental data.     

Calculation and analysis of proton-induced reactions on Ni at incident energies from threshold to 200 MeV

Proton-induced reactions on ⁵⁸Ni have been studied in the energy range from threshold to 200 MeV. Based on experimental data of elastic scattering angular distributions and nonelastic cross section, an optimal set of proton optical potential parameters for ⁵⁸Ni has been obtained. All cross sections, elastic and inelastic scattering angular distributions, energy spectra and especially double differential cross sections for neutrons, protons, deuterons, tritons, helium particles and alpha particles emission have been calculated, using nuclear models theory. Theoretical calculations have been compared with existing experimental data, in most cases, the calculated results are in good agreement with the experimental data.     

Calculation and evaluations for n+Cu reactions

All cross sections of neutron induced reactions, angular distributions, energy spectra and double differential cross sections are consistently calculated and analyzed for n+^63,65,nat.Cu reactions at incident neutron energies below 200 MeV based on the nuclear theoretical models. The optical model, preequilibrium and equilibrium reaction theories, the distorted wave Born approximation theory are used. Theoretical calculated results are compared with existing experimental data and the evaluated results in ENDF/B-VII and JENDL-3 libraries. The optical model potential parameters are obtained according to the experimental data of total, nonelastic scattering cross sections and elastic scattering angular distributions.     

Double differential cross sections of neutron and proton emission in neutron induced reactions on Fe

The energy spectra and double differential cross sections of neutron and proton emissions for n+^54,56,57,58Fe reactions are studied at incident neutron energies below 200 MeV based on the nuclear theoretical models, which are based on pre-equilibrium and equilibrium reaction theories. Theoretical calculated results are compared with existing experimental data.     

Calculation and analysis of p + Ca reaction cross sections at incident energies from threshold to 250 MeV

All cross sections, angular distributions and energy spectra of neutron, proton, deuteron, triton, helium, alpha particle emission for p + ^{40,42,43,44,46,48,nat}Ca reactions have been calculated and analyzed at incident proton energies from threshold to 250 MeV by nuclear theoretical models. The theoretical calculated results are in good agreement with existing experimental data.     

Low-energy electron elastic scattering cross sections for excited Au and Pt atoms

Electron elastic total cross sections (TCSs) and differential cross sections (DCSs) in both impact energy and scattering angle for the excited Au and Pt atoms are calculated in the electron impact energy range 0 ? E ? 4.0 eV. The cross sections are found to be characterized by very sharp long-lived resonances whose positions are identified with the binding energies of the excited anions formed during the collisions. The recent novel Regge-pole methodology wherein is embedded through the Mulholland formula the electron-electron correlations is used together with a Thomas-Fermi type potential incorporating the crucial core-polarization interaction for the calculations of the TCSs. The DCSs are evaluated using a partial wave expansion. The Ramsauer-Townsend minima, the shape resonances and the binding energies of the excited Au⁻ and Pt⁻ anions are extracted from the cross sections, while the critical minima are determined from the DCSs.     

Some cross sections of Bromine isotopes induced by 14 MeV neutrons

Activation cross sections of Bromine isotopes induced by 14 MeV neutrons were measured. The cross sections for three (n, 2n), two (n, p) and one (n, α) reactions are reported in this work. The cross sections for ⁸¹Br (n, 2n) ^80gBr, ⁸¹Br (n, 2n) ^80mBr and ⁸¹Br (n, p) ^81gSe reactions at neutron energy of 13.5 MeV; and ⁸¹Br (n, p) ^81gSe at 14.1 MeV are given for the first time. The measured results are discussed and compared with the previous works.     

Low-energy electron elastic collision cross sections for ground and excited Tm, Lu and Hf atoms

Low-energy 0 ? E ? 1.0 eV electron elastic scattering from ground and excited Tm, Lu and Hf atoms has been investigated. Both total and differential cross sections have been calculated; the latter at the scattering angles θ = 0°, 90° and 180°. The recent Regge-pole methodology has been used for the calculations. In the method the crucial electron-electron correlation effects are accounted for through the Mulholland formula. We find that the total cross sections are characterized generally by shape resonances, Ramsauer-Townsend minima and dramatically sharp long-lived resonances from which we extract the binding energies of the negative ions. Our extracted binding energy of the Hf⁻ negative ion from the total cross section is compared with that of Pan and Beck [14].     

Alkali ion scattering from Ag(0 0 1) and Ag thin films at low and hyperthermal energies

We have investigated the scattering of K⁺ and Cs⁺ ions from a single crystal Ag(0 0 1) surface and from a Ag-Si(1 0 0) Schottky diode structure. For the K⁺ ions, incident energies of 25 eV to 1 keV were used to obtain energy-resolved spectra of scattered ions at θ_i = θ_f = 45°. These results are compared to the classical trajectory simulation safari and show features indicative of light atom-surface scattering where sequential binary collisions can describe the observed energy loss spectra. Energy-resolved spectra obtained for Cs⁺ ions at incident energies of 75 eV and 200 eV also show features consistent with binary collisions. However, for this heavy atom-surface scattering system, the dominant trajectory type involves at least two surface atoms, as large angular deflections are not classically allowed for any single scattering event. In addition, a significant deviation from the classical double-collision prediction is observed for incident energies around 100 eV, and molecular dynamics studies are proposed to investigate the role of collective lattice effects. Data are also presented for the scattering of K⁺ ions from a Schottky diode structure, which is a prototype device for the development of active targets to probe energy loss at a surface.     

The (He, tf) as a surrogate reaction to determine (n, f) cross sections in the 10-20 MeV energy range

The surrogate reaction ²³⁸U(³He, tf) is used to determine the ²³⁷Np(n, f) cross section indirectly over an equivalent neutron energy range from 10 to 20 MeV. A self-supporting ∼761 μg/cm² metallic ²³⁸U foil was bombarded with a 42 MeV ³He²⁺ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS) consisted of two 140 μm and one 1000 μm Micron S2 type silicon detectors. The ²³⁷Np(n, f) cross sections, determined indirectly, were compared with the ²³⁷Np(n, f) cross section data from direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets. Use of the (³He, tf) reaction as a surrogate to extract (n, f) cross sections in the 10-20 MeV equivalent neutron energy range is found to be suitable.     

Non-dipole second order parameters of the photoelectron angular distribution for elements Z = 1-100 in the photoelectron energy range 1-10 keV

Presented here are the photoelectron angular distribution non-dipole parameters associated with the terms of the second order O [(kr)²] (k is the photon energy and r is the radius of the ionized atomic shell) for both unpolarized and linearly polarized radiation. The parameters are given for atomic shells with binding energies lower than 2 keV of all elements 1 ? Z ? 100 for four values of photoelectron energy in the range 1−10 keV. In this range, the second-order terms are shown to make a significant contribution (up to ∼30%) to the angular differential cross section. The inclusion of these terms becomes all the more important in calculations of the differential cross section ratio for the fixed geometry of angles which is measured experimentally in the case of linearly polarized radiation. The Dirac-Fock-Slater potential is used in the calculations. The hole left by the emitted electron is taken into account in the frozen orbital approximation.     

Validation of nuclear reaction models of 180 MeV proton-induced fragmentation of Al

Kinetic energy, angular distribution, and isobaric cross section data for A = 7-25 fragments formed in p + ²⁷Al reaction at bombarding energy of 180 MeV are compared with the calculations of the Binary Cascade Model (BIC), the Cascade Exciton Model (CEM), JQMD/PHITS, as well as the Statistical Model with Final State Interaction (SMFSI). For completeness, the kinetic energy spectra of light particles (n, p, α) formed in p + ²⁷Al reaction at bombarding energy of 156 MeV are also presented. A general agreement between the data and predictions of these models is found. However, disagreement with the data for the yields of light-mass fragments as well as near-target fragments is also found and discussed. The importance of this comparative study to simulation and analysis of radiation effects on microscopic electrical components operating in space is also discussed.     

Cross sections for transfer ionization in ion-helium collisions

A simple model has been developed within the independent-particle model (IPM) based on the Bohr-Lindhard model and classical statistical model. Cross sections for transfer ionization of helium by ions A^q+ (q = 1-3) are calculated for impact energies between 10 and 6000 keV/u. The calculated cross sections are in good agreement with the experimental data of helium by He^(1-2)+ and Li^(1-3)+.     

Molybdenum L-shell X-ray production by 350-600 keV Xe (q = 25-30) ions

Molybdenum L-shell X-rays were produced by Xe^q+ (q = 25-30) bombardment at low energies from 2.65 to 4.55 keV/amu (350-600 keV). We observed a kinetic energy threshold of Mo L-shell ionization down to 2.65-3.03 keV/amu (350-400 keV). The charge state effect of the incident ions was not observed which shows that the ions were neutralized, reaching an equilibrium charge state and losing their initial charge state memory before production of L-shell vacancies resulted in X-ray production. The experimental ionization cross sections were compared with those from Binary Encounter Approximation theory. Taking into account projectile deflection in the target nuclear Coulomb field, the ionization cross section of Mo L-shell near the kinetic energy threshold was well described.     

Calculation and evaluation of cross-sections for p+Fe reactions up to 250 MeV

All cross-sections of proton-induced reactions, angular distributions and the energy spectra of neutron, proton, deuteron, triton, helium and alpha-particle emission are consistent calculated and analyzed for p+^{54,56,57,58,nat}Fe at incident proton energies below 250 MeV by using nuclear theoretical models which integrate the optical model, the intra-nuclear cascade model, direct, preequilibrium and equilibrium reaction theories. Especially, the cross-sections of the light composite particle (d, t, ³He and α) emissions are improved based on the exciton model including the pick-up mechanism. Theoretical calculated results are compared with existing experimental data.