Inelastic Scattering Cross Sections Research Articles

Comparative study of alpha scattering from various nuclei at 130 MeV: Microscopic potentials and coupled channel calculations

The angular distributions of the elastic and inelastic scattering cross sections of alpha projectiles on different heavy ion target nuclei including 12C, 16O, 24Mg, 28Si and 40Ca at energy of 130 MeV have been studied using two different microscopic real potentials generated by the energy density functional (EDF) theory, and single folding cluster model as well as phenomenological Woods-Saxon potentials. A new parameterization was considered for the first time by EDF and to make the normalization coefficient tend to unity, it is necessary to consider correction to the calculated real potential. Coupled channel calculations for various low-lying states were performed, and the best fit values for the deformation length with the above models were extracted by fitting the inelastic scattering cross section and compared to previous work values. The total reaction cross section, as well as the real and imaginary volume integrals, have been studied.

High-Energy Collision of Quarks and Mesons in the Schwinger Model: From Tensor Networks to Circuit QED.

With the aim of studying nonperturbative out-of-equilibrium dynamics of high-energy particle collisions on quantum simulators, we investigate the scattering dynamics of lattice quantum electrodynamics in 1+1 dimensions. Working in the bosonized formulation of the model and in the thermodynamic limit, we use uniform-matrix-product-state tensor networks to construct multiparticle wave-packet states, evolve them in time, and detect outgoing particles post collision. This facilitates the numerical simulation of scattering experiments in both confined and deconfined regimes of the model at different energies, giving rise to rich phenomenology, including inelastic production of quark and meson states, meson disintegration, and dynamical string formation and breaking. We obtain elastic and inelastic scattering cross sections, together with time-resolved momentum and position distributions of the outgoing particles. Furthermore, we propose an analog circuit-QED implementation of the scattering process that is native to the platform, requires minimal ingredients and approximations, and enables practical schemes for particle wave-packet preparation and evolution. This study highlights the role of classical and quantum simulation in enhancing our understanding of scattering processes in quantum field theories in real time.

Calculation And Uncertainty Analysis of Core Parameters of ALMANAR Reactor Using New Nuclear Data Libraries

Abstract A small modular lead-cooled fast spectrum core concept called ALMANAR designed to produce 45 MWth power for 22 years operating without refuelling was proposed in a previous study. The neutronics investigation showed its excellent inherent safety features. It could be considered as a candidate for future electricity source for the near future. It is noteworthy that the target accuracy for eigenvalue calculation for keff regardless of spectrum is set to 300 pcm. However, findings in this analysis revealed that the keff uncertainty was larger for the recently released nuclear data libraries (about 800 pcm), mostly from 235U capture cross section (624 pcm) in the case of ENDF/B-VIII.0 and 238U inelastic scattering cross section (437 pcm) in the case of JENDL-5. Selected kinetic parameters of the ALMANAR core and their uncertainty were also evaluated and analysed. No major impact on the total ßeff, leffeff and λeff simulation results was found. In order to improve the reliability of criticality calculations of the lead-cooled small fast reactor, the accuracy of capture and fission cross section of 235,238U, the capture cross section of 10B and the elastic scattering cross section of 208Pb at the fast energy range of ENDF/B-VIII.0 should be improved. Furthermore, the inelastic scattering and capture cross section of 238U, fission and capture cross section of 235U and the capture cross section of 10B of JENDL-5 should also be improved.

Modelling dynamical 3D electron diffraction intensities. II. The role of inelastic scattering.

The strong interaction of high-energy electrons with a crystal results in both dynamical elastic scattering and inelastic events, particularly phonon and plasmon excitation, which have relatively large cross sections. For accurate crystal structure refinement it is therefore important to uncover the impact of inelastic scattering on the Bragg beam intensities. Here a combined Bloch wave-Monte Carlo method is used to simulate phonon and plasmon scattering in crystals. The simulated thermal and plasmon diffuse scattering are consistent with experimental results. The simulations also confirm the empirical observation of a weaker unscattered beam intensity with increasing energy loss in the low-loss regime, while the Bragg-diffracted beam intensities do not change significantly. The beam intensities include the diffuse scattered background and have been normalized to adjust for the inelastic scattering cross section. It is speculated that the random azimuthal scattering angle during inelastic events transfers part of the unscattered beam intensity to the inner Bragg reflections. Inelastic scattering should not significantly influence crystal structure refinement, provided there are no artefacts from any background subtraction, since the relative intensity of the diffracted beams (which includes the diffuse scattering) remains approximately constant in the low energy loss regime.

Assessment of unmixing approaches for the quantitation of SERS nanoparticles in highly multiplexed spectral images

AbstractSurface‐enhanced Raman scattering nanoparticles (SERS NPs) offer powerful optical contrast features for imaging assays. Their gold core enhances the inelastic scattering cross section, allowing highly sensitive and rapid detection, and their characteristic sets of narrow spectral bands give them unsurpassed multiplexing capabilities. Multiplexed hyperspectral images are commonly unmixed using a compensation matrix of reference spectra to produce quantitative image channels illustrating the distribution of each material. It is these unmixed channels that are fit for interpretation from assays utilizing SERS NP contrast agents. Some factors that may impact SERS NP quantitative and dynamic range capabilities may include endogenous background heterogeneity, the ability of unmixing algorithms to account for signal variances, and linear system conditioning imposed by contrast agent signals. We report on hyperspectral Raman imaging of mixtures of SERS NPs from an expanded library of contrast agents. We study increasing plexity and varying degrees of system conditioning as inputs to a diverse set of classical, non‐negatively constrained, and regularized regression algorithms to investigate which signal features and unmixing methods deliver the most promising quantitation performance with the least error. Raman imaging of SERS NP mixtures is performed on controlled substrates and representative biological specimens, and experimental results are compared against ground truth data. We evaluate spectral fitting fidelity, quantitation, and specificity correlations with system conditioning. Spectral unmixing with a regularized hybrid of least squares regression with principal component analysis (HLP) algorithm approximated spectra with 3.5× better fitting fidelity and 3× better quantitation robustness with tissue background compared with simpler unmixing routines.

GENESIS: Gamma Energy Neutron Energy Spectrometer for Inelastic Scattering

Improved neutron inelastic scattering cross section data are needed to inform integral benchmark studies and advance applications in a wide variety of areas including nuclear energy, stockpile stewardship, nonproliferation, and space exploration. Neutron inelastic scattering also serves as a non-selective probe of low-lying nuclear structure. To help meet these needs, the Gamma Energy Neutron Energy Spectrometer for Inelastic Scattering (GENESIS) was constructed at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. This array couples high-resolution γ-ray detectors and fast neutron detectors to achieve single and coincident n/γ detection over a broad energy range. The current configuration of the array includes 26 organic liquid scintillators and four high-purity germanium detectors (two single-crystal and two four-crystal CLOVER detectors with two-fold segmentation). The array was constructed with minimal supporting material and designed to cover a wide range of secondary particle angles and energies with limited inter-element scattering. Data acquisition is accomplished using Mesytec MDPP-16 multi-channel high-resolution digital pulse processing modules. The array characteristics, including γ-ray and neutron energy resolution, timing resolution, and detection efficiency were measured and used to validate a Geant4 model of the array. The primary sources of neutron background and the uncertainties in the determination of incident and secondary neutron energy were assessed. GENESIS provides a new capability to address nuclear data needs and facilitates the advancement of a wide range of nuclear applications.

Impact of Uncertainty Reduction on Lead-Bismuth Coolant in Accelerator-Driven System Using Sample Reactivity Experiments

In this study, we have demonstrated that data assimilation (DA) using lead and bismuth sample reactivities measured in the Kyoto University Critical Assembly A-core can successfully reduce the uncertainty of the coolant void reactivity in accelerator-driven systems (ADSs) derived from inelastic scattering cross sections of lead and bismuth. We reevaluated and highlighted the experimental uncertainties and correlations of the sample reactivities for the DA formula. We used the MCNP6.2 code to evaluate the sample reactivities and their uncertainties and performed DA using the reactor analysis code system MARBLE. The high-sensitivity coefficients of the sample reactivities to lead and bismuth allowed us to reduce the cross-section–induced uncertainty of the void reactivity of the ADS from 6.3% to 4.8%, achieving a provisional target accuracy of 5% in this study. Furthermore, we demonstrated that the uncertainties arising from other dominant factors, such as minor actinides and steel, can be effectively reduced by using integral experimental data sets for the unified cross-section dataset ADJ2017.

A multimodal neutron-based technique for the elemental analysis of materials in bulk

Neutrons and gamma rays are effective probes for the elemental characterisation of bulk samples. Neutrons interactions with matter are characteristic of the nature of the target nucleus, and the incident neutron energy. Most nuclides exhibit distinctive structure in their total and differential cross sections, thus elements can be differentiated via their total, elastic and inelastic scattering cross sections, and the energies of prompt gamma rays produced in inelastic collisions. In this work we report on the use of the fast neutron transmission analysis technique for the analysis of 12C in graphite. We also present results of prompt gamma ray neutron activation analysis of graphite using 14 MeV neutrons, which was explored for the purpose of developing a multimodal neutron-based technique for elemental analysis of materials in bulk.

How is the Signal Attenuation in Surface Electron Spectroscopy Described? V. Description of Electron Inelastic Scattering Cross Sections for Solid Using Dielectric Function

How is the Signal Attenuation in Surface Electron Spectroscopy Described? V. Description of Electron Inelastic Scattering Cross Sections for Solid Using Dielectric Function

Electron impact excitation of Sn^{2+}

The relativistic convergent close-coupling method is applied to calculate integrated cross sections for the electron-impact excitation of Sn^{2+}. Cross sections have been calculated for excitations to all states in the 5s5p, 5p^2, 5s6s and 5s5d manifolds from the ground state for projectile electron energies ranging from 24 eV to 500 eV. The total discrete inelastic scattering cross section is also presented.Graphical abstract

Theoretical Investigation of Electron Impact Scattering on Imidazole.

This study presents the results of electron scattering calculations on a biologically important molecule, imidazole, using the UK molecular R-matrix method. The R-matrix calculations are performed using SE, SEP, and CC models, and the resonance detected in the present SEP model is found to be in better agreement with available experimental data than previous theoretical data. The study also reports an inelastic scattering cross section, which comprises dissociative electron attachment (DEA), excitation, and ionization cross section, for the first time. The total scattering cross sections are also reported for the first time. We confirm the presence of the two well-known π* shape resonances predicted earlier experimentally. Due to the scarcity of total scattering cross section (TCS) data for imidazole, we have compared the TCS of imidazole with its isoelectronic target isoxazole and drawn important conclusions. A comparison among the resonances of imidazole with those of isoxazole helps us to conclude that electron attachment to π* molecular orbitals is a general feature displayed by these five-membered heterocyclic compounds. The comprehensive electron scattering studies presented in this work are expected to provide a deeper understanding of electron-induced biochemical processes and fill gaps in the available data. Furthermore, this study is anticipated to inspire further investigations on imidazole and other five-membered heterocyclic ring molecules, which have significant applications in medicine.

Study of HPGe detector shielding for use in inelastic neutron scattering experiments at the n_TOF/CERN facility

The study of inelastic scattering reactions is important both in basic research as it can provide an insight on nuclear structure and aid in the validation of theoretical models, as well as in the field of applications. The most frequently used method to determine the neutron induced inelastic scattering cross section is by recording the emitted gamma rays from the de-excitation of the target nucleus. In this direction, the high energy resolution of the HPGe detectors is instrumental. The experimental setup can be further improved by shielding the HPGe against the scattered neutrons. The purpose of this work is to investigate the contribution of such shieldings used in inelastic neutron scattering experiments at the n_TOF facility at CERN and to optimise the experimental set-up. In this study, GEANT4, a package for simulating the transport of radiation through matter, was used to study the effect of the various shielding materials and geometries for CANBERRA’s EGPC 25S/N 540 p-type coaxial prototype HPGe.

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.

Basics of factorization in a scalar Yukawa field theory

The factorization theorems of QCD apply equally well to most simple quantum field theories that require renormalization but where direct calculations are much more straightforward. Working with these simpler theories is convenient for stress testing the limits of the factorization program and for examining general properties of the parton density functions or other correlation functions that might be necessary for a factorized description of a process. With this view in mind, we review the steps of factorization in a real scalar Yukawa field theory for both deep inelastic scattering and semi-inclusive deep inelastic scattering cross sections. In the case of semi-inclusive deep inelastic scattering, we illustrate how to separate the small transverse momentum region, where transverse momentum dependent parton density functions are needed, from a purely collinear large transverse momentum region, and we examine the influence of subleading power corrections. We also review the steps for formulating transverse momentum dependent factorization in transverse coordinate space, and we study the effect of transforming to the well-known ${b}_{*}$ scheme. Within the Yukawa theory, we investigate the consequences of switching to a generalized parton model approach and compare it with a fully factorized approach. Our results highlight the need to address similar or analogous issues in QCD.

Selecting resonances in molecular scattering by anti-Zeno effect.

Utilizing the anti-Zeno effect, we demonstrate that the resonances of ultracold molecular interactions can be selectively controlled by modulating the energy levels of molecules with a dynamic magnetic field. We show numerically that the inelastic scattering cross section of the selected isotopic molecules in the mixed isotopic molecular gas can be boosted for 2-3 orders of magnitude by modulation of Zeeman splittings. The mechanism of the resonant anti-Zeno effect in the ultracold scattering is based on matching the spectral modulation function of the magnetic field with the Floquet-engineered resonance of the molecular collision. The resulting insight provides a recipe to implement resonant anti-Zeno effect in control of molecular interactions, such as the selection of reaction channels between molecules involving shape and Feshbach resonances, and external field-assisted separation of isotopes.

Comparative Investigation of XPS Spectra of Oxidated Carbon Nanotubes and Graphene

X-ray photoelectron emission spectra of thermally reduced graphene oxide samples and carbon nanotubes (CNTs) with various oxidation degrees are presented in this paper. A method for the reconstruction of differential electron inelastic scattering cross sections from the energy loss spectra of photoelectrons is described and discussed. The analysis of the part of the characteristic photoelectron energy loss spectrum adjacent to the C1 peak indicated a considerable influence of the thermal reduction of graphene oxide on the electron properties of the samples obtained. On the contrary, the oxidation of CNTs by refluxing in a concentrated HNO3 solution does not change the free electron excitation spectrum.

Electron transmission and mean free path in molybdenum disulfide at electron-volt energies

In van der Waals (vdW) materials, the electron mean free path (MFP) is largely influenced by the discrete states in the unoccupied band structure. So far, the influence of these states has only been measured in graphene, while all measurements on other vdW materials lack energy resolution. Here, we present reflection and transmission spectra of freestanding, few-layered molybdenum disulfide $(\mathrm{Mo}{\mathrm{S}}_{2})$ samples in the $0--55$ eV electron range. Our measurements reveal states of enhanced electron transmissivity above the vacuum level, that correspond to the (unoccupied) density of states. We also show a full quantum-mechanical calculation that confirms a good understanding of the elastic scattering in $\mathrm{Mo}{\mathrm{S}}_{2}$. A model is developed to extract the inelastic MFP spectrum, which is a measure of the inelastic scattering cross section. As $\mathrm{Mo}{\mathrm{S}}_{2}$ is a complicated system of different atomic planes, we expect that our methods generalize well to other van der Waals materials and heterostacks thereof.

The CH-3Σ+ Anion: Inelastic Rate Coefficients from Collisions with He at Interstellar Conditions.

We present accurate ab initio calculations on several properties of a gas-phase system of interest in the interstellar medium (ISM), where the title molecular anion has been often surmised but not yet confirmed by observations. The CH-3Σ+ constitutes the smallest term in the series of longer anionic polyynes which have been observed in the ISM (e.g., C4H- and several others). Hence, its dynamical behavior in collision with He atoms, one of the most abundant atoms in that environment, can provide quantitative indicators on the changes which can occur in the rotational state population of the title anion when driven by this collision dynamics. We therefore report an accurate evaluation of the full potential energy surface (PES) which acts between the molecular anion in its ground vibrational state and the He atom. The relevant inelastic scattering cross sections and the corresponding inelastic rate coefficients are then computed within a quantum treatment of the collisions. We find that the fairly small values of the final inelastic rate coefficients indicate state-changing processes by collisions to be inefficient paths for modifying the rotational state populations of this anion and therefore to aid its possible observation from direct radiative emission in the microwave region.

Templates of expected measurement uncertainties for (n, xn) cross sections

A template is provided for evaluating experimental uncertainties for neutron elastic and inelastic scattering cross sections andγ-ray production cross sections from (n, xn) measurements at laboratories with monoenergetic or white neutron sources. A typical range of uncertainties is presented for experiments detecting the scattered neutrons or the resulting de-excitationγrays based on a survey of available data and input from many experimentalists and theorists with extensive knowledge in the field. Models commonly used to evaluate the resulting cross-sections are also discussed. Suggestions are made regarding what experimental and uncertainty information is needed for data evaluations and should be included when reporting experimental (n, xn) cross sections. Uncertainty values and correlations are recommended if these values cannot be estimated for past data from the literature.

From 232Th(n, n’γ) cross sections to level production and total neutron inelastic scattering cross sections

To probe the neutron inelastic scattering off 232Th, an experiment took place at the EC-JRC Geel conducted with the experimental setup GRAPhEME to detect emitted γ-rays. The prompt γ-ray spectroscopy method was used and 70 experimental 232Th(n, n’γ) cross sections were obtained from the experimental data. Combining these cross sections, nuclear-structure data available in databases and hypotheses to complete the latter, neutron inelastic level production cross sections in 232Th and the total inelastic cross section were calculated. For the first time, the total inelastic cross section of an actinide nucleus was derived on the total neutron energy range from experimental data only. Comparisons of (n, n’) cross section data with evaluated data reveal a good agreement between them all above 300 keV of neutron energy. TALYS calculations are compatible but lower than the evaluated data.