Interaction Cross Sections Research Articles

Investigation of positron scattering from 2H-pyran, 4H-pyran, and pyrrole molecules

Abstract The scattering cross-sections for positron-biomolecule interaction are an essential input for the Monte-Carlo simulation techniques. In the present work, we have reported the elastic integral, differential, momentum transfer, and total ionization cross-sections for scattering of positron from 2H-pyran, 4H-pyran, and pyrrole molecules. The single-center expansion (SCE) method is employed for the elastic scattering calculations and the binary-encounter-Bethe model for ionization. We have also reported the elastic integral and differential cross-sections for benzene and furan, which are structurally similar to the pyran isomers and pyrrole, respectively, and compared them with the experimental and theoretical data available in the literature to validate the efficacy of the SCE method and the codes used. A comparative analysis of the elastic cross-sections for the isomers: 2H-pyran and 4H-pyran, and the pyrrole molecule that is isoelectronic with furan is also presented.

Nuclear interaction correction based on dual-energy computed tomography in carbon-ion radiotherapy.


Accurate dose predictions are crucial to maximizing the benefits of carbon-ion therapy. Carbon beams incident on the human body cause nuclear interactions with tissues, resulting in changes in the constituent nuclides and leading to dose errors that are conventionally corrected using conventional single-energy computed tomography (SECT). Dual-energy computed tomography (DECT) has frequently been used for stopping power estimation in particle therapy and is well suited for correcting nuclear reactions because of its detailed body-tissue elemental information. This study proposes a correction method for the absolute dose in carbon-ion therapy that considers changes in nuclide composition resulting from nuclear reactions with body tissues, as a novel application of DECT.
Approach:
The change in dose associated with nuclear reactions is determined by correcting each integrated depth dose component of the carbon beam using a nuclear interaction correction factor. This factor is determined based on the stopping power, mass density, and nuclear interaction cross-section in body tissue. The stopping power and mass density were calculated using established methods, whereas the nuclear interaction cross-section was newly defined through a conversion equation derived from the effective atomic number.
Main results:
Nuclear interaction correction factors and corrected doses were determined for 85 body tissues with known compositions, comparing them with existing SECT-based methods. The root-mean-square errors of the SECT- and DECT-based nuclear interaction correction factors relative to theoretical values were 0.66% and 0.39%, respectively.
Significance:
This indicates a notable enhancement in the estimation accuracy with DECT. The dose calculations in uniform body tissues derived from SECT showed slight over-correction in adipose and bone tissues, whereas those based on DECT were almost consistent with theoretical values. Our proposed method demonstrates the potential of DECT for enhancing dose calculation accuracy in carbon-ion therapy, complementing its established role in stopping power estimation.&#xD.

Investigation of positron scattering from 2H-pyran, 4H-pyran, and pyrrole molecules

Abstract The scattering cross-sections for positron-biomolecule interaction are an essential
 input for the Monte-Carlo simulation techniques. In the present work, we have reported
 the elastic integral, differential, momentum transfer, and total ionization cross-sections for
 scattering of positron from 2H-pyran, 4H-pyran, and pyrrole molecules. The single-center
 expansion method is employed for the elastic scattering calculations and the binary-encounter
Bethe model for ionization. We have also reported the elastic integral and differential cross
sections for benzene and furan, which are structurally similar to the pyran isomers and pyrrole,
 respectively, and compared them with the experimental and theoretical data available in the
 literature to validate the efficacy of the single-center expansion method and the codes used.
 Acomparative analysis of the elastic cross-sections for the isomers: 2H-pyran and 4H-pyran,
 and the pyrrole molecule that is isoelectronic with furan is also presented.

Optical parameters and shielding attitude of sodium fluoride in calcium-borate glasses

Borate glasses with compositions xCaO-(30-x)NaF-70B2O3 (x = 0–30 mol%, step 5) were synthesized and characterized to investigate the effects of partially substituting NaF with CaO on radiation shielding ability and optical properties. Density, molar volume, packing density, and free volume were measured and calculated. UV–visible spectroscopy was utilized to determine the optical bandgap and other correlated physical parameters. Moreover, different shielding parameters were evaluated using Phy-X simulation software. From data analyses, it was found that increasing CaO content transformed BO3 to BO4 structural units in the borate glass network, keeping the optical bandgap values between 3.76 and 3.55 eV. In addition, the refractive index varied from 2.32 to 2.4, while molar refractivity and Urbach energy were slightly increased with composition. Moreover, the replacement of NaF by CaO enhanced photon interaction cross-sections, reducing the mean free path and half-value layer. The work demonstrated that controlled additions of an intermediate oxide like CaO can tailor the radiation shielding and optical characteristics of borate glasses for potential applications as transparent radiation shielding materials.

DarkSide-20k sensitivity to light dark matter particles

The dual-phase liquid argon time projection chamber is presently one of the leading technologies to search for dark matter particles with masses below 10 GeV c−2. This was demonstrated by the DarkSide-50 experiment with approximately 50 kg of low-radioactivity liquid argon as target material. The next generation experiment DarkSide-20k, currently under construction, will use 1,000 times more argon and is expected to start operation in 2027. Based on the DarkSide-50 experience, here we assess the DarkSide-20k sensitivity to models predicting light dark matter particles, including Weakly Interacting Massive Particles (WIMPs) and sub-GeV c−2 particles interacting with electrons in argon atoms. With one year of data, a sensitivity improvement to dark matter interaction cross-sections by at least one order of magnitude with respect to DarkSide-50 is expected for all these models. A sensitivity to WIMP–nucleon interaction cross-sections below 1 × 10−42 cm2 is achievable for WIMP masses above 800 MeV c−2. With 10 years exposure, the neutrino fog can be reached for WIMP masses around 5 GeV c−2.

Attenuation of cosmic ray electron boosted dark matter

We consider a model of boosted dark matter (DM), where a fraction of DM is upscattered to relativistic energies by cosmic ray electrons. Such interactions responsible for boosting the DM also attenuate its flux at the Earth. Considering a simple model of constant interaction cross section, we make analytical estimates of the variation of the attenuation ceiling with the DM mass and confirm it numerically. We then extend our analysis to a Z′-mediated leptophilic DM model. We show that the attenuation ceiling remains nearly model independent for DM and mediator particles heavier than the electron, challenging some previous discussions on this topic. Using the XENONnT direct detection experiment, we illustrate how constraints based on energy-dependent scattering can significantly differ from those based on an assumed constant cross section. This highlights the importance of reevaluating these constraints in the context of specific models. Published by the American Physical Society 2024

Unveiling radii and neutron skins of unstable atomic nuclei via nuclear collisions

Total reaction, interaction, and charge-changing cross sections, which are kinds of cross sections standing for total nuclear collision probability in medium-to high-energy region from a few to several hundred MeV, have been extensively utilized to probe nuclear sizes especially for unstable nuclei. In this mini review, experimental techniques and recent findings from these cross sections are briefly overviewed. Additionally, two new methods to extract neutron skin thickness solely from the above cross sections are explained: One is utilizing the energy and isospin dependence of the total reaction cross sections, and the other is the combination of the total reaction and charge-changing cross section measurements.

The study of hadronic rescattering on K∗0 resonance yield in baryon-rich QCD matter

Abstract The effect of hadronic rescattering on K ∗0 resonance yield can be studied by measuring K ∗0/K ratio as a function of centrality or multiplicity. This study investigates how the size of the system and the chemical composition (meson–meson versus meson–baryon interaction) of the matter formed in heavy-ion collisions impact the process of hadronic rescattering. It is shown that existing calculation of K ∗0/K ratio, which considers the interaction of K ∗0 and K mesons with only light mesons in the hadronic medium (neglecting interactions with baryons), fails to explain the measured K ∗0/K ratio at RHIC beam energy scan (BES) energies. To understand the multiplicity dependence of the K ∗0/K ratio at RHIC BES and SPS energies ( s NN < 20 GeV), the ultra relativistic quantum molecular dynamics (UrQMD) model is employed. UrQMD calculations suggest that for a given multiplicity, K ∗0/K is more suppressed in Au+Au collision at s NN = 7.7 GeV, compared to that in s NN = 200 GeV. This is possibly because of formation different type of quantum chromodynamics medium at 200 and 7.7 GeV, and change in interaction cross-section between hadrons with change in particle type and energy.

Recent Results from the FASER Experiment at the LHC

The ForwArd Search ExpeRiment (FASER), is an LHC experiment that aims to: (1) detect and study TeV-energy neutrinos, the most energetic neutrinos ever detected from a humanmade source and (2) search for new light and very weakly interacting particles. The FASER detector is located 480 m downstream of the ATLAS p-p interaction point, along the beam collision axis. FASER was designed, constructed, installed, and commissioned during 2019–2022 and has been taking physics data since the start of LHC Run 3 in July 2022. Recently, FASER reported the first measurement of ve and vμ interaction cross sections at the LHC with its sub-detector FASERv , FASER’s emulsion detector, first results on Axion-Like Particles at FASER and dark photons limits. These results will be reported in this article.

Investigation of the Nuclear Cross-Sections for Proton Capture Reactionsin the Star Formation Process of the Galaxies

Understanding the CNO cycle and the proton-proton (p-p) chain is essential for comprehending the development of main sequence stars in the initial stages of spiral and elliptical galaxy formation. This study investigates two nuclear reactions that occur in spiral galaxies and elliptical galaxies. Using theoretical computer software (e.g. OriginPro. software program), we summarized the excitation functions to analyze the (p,γ) interaction cross sections of 7Be(p,γ)8B, 12C(p,γ)13N, 14N(p,γ)15O, and 15N(p, γ)12C. In the p-p series and CNO cycle with energy up to 8 MeV. In this work, we compared the theoretical values from the ENDF/B-VII library with the estimated database of nuclear fusion cross sections in hydrogen-burning stellar objects from CSC-GM and TALYS. For these nuclei, cross sections can be calculated at low energies within the pp chain and CNO cycle. Therefore, we were able to calculate only four finite elements in the CNO cycle and the pp series.

MATXCOM—an x-ray/gamma-ray attenuation calculator for arbitrary materials based on EPICS2023 evaluated photon data library

A program called MATXCOM was developed for the calculation of x-ray/gamma-ray interaction cross-sections, the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half and tenth value layers (HVL and TVL), mean free path (MFP), total atomic and electronic cross-sections (ACS and ECS), effective atomic number (Zeff), effective electron density (Neff), effective conductivity (Ceff), and energy absorption and exposure buildup factors (EABF and EBF) for arbitrary materials based on the EPICS2023 evaluated photon data library (EPDL). MATXCOM was implemented as a stand-alone program written in Fortran featuring a streamlined input/output interface. This design allows it to be easily integrated into scripts or wrapper functions, making it adaptable for use in large computational projects.

Nanodosimetric investigation of the track structure of therapeutic carbon ion radiation part2: detailed simulation

Objectivea previous study reported nanodosimetric measurements of therapeutic-energy carbon ions penetrating simulated tissue. The results are incompatible with the predicted mean energy of the carbon ions in the nanodosimeter and previous experiments with lower energy monoenergetic beams. The purpose of this study is to explore the origin of these discrepancies.Approachdetailed simulations using the Geant4 toolkit were performed to investigate the radiation field in the nanodosimeter and provide input data for track structure simulations, which were performed with a developed version of the PTra code.Main resultsthe Geant4 simulations show that with the narrow-beam geometry employed in the experiment, only a small fraction of the carbon ions traverse the nanodosimeter and their mean energy is between 12% and 30% lower than the values estimated using the SRIM software. Only about one-third or less of these carbon ions hit the trigger detector. The track structure simulations indicate that the observed enhanced ionization cluster sizes are mainly due to coincidences with events in which carbon ions miss the trigger detector. In addition, the discrepancies observed for high absorber thicknesses of carbon ions traversing the target volume could be explained by assuming an increase in thickness or interaction cross-sections in the order of 1%.Significancethe results show that even with strong collimation of the radiation field, future nanodosimetric measurements of clinical carbon ion beams will require large trigger detectors to register all events with carbon ions traversing the nanodosimeter. Energy loss calculations of the primary beam in the absorbers are insufficient and should be replaced by detailed simulations when planning such experiments. Uncertainties of the interaction cross-sections in simulation codes may shift the Bragg peak position.

Inelastic Cross Sections of Interaction of Relativistic Heavy Nuclei

Inelastic Cross Sections of Interaction of Relativistic Heavy Nuclei

Dark matter (h)eats young planets

We study the effect of dark matter annihilation on the formation of Jovian planets. We show that dark matter heat injections can slow or halt Kelvin-Helmholtz contraction, preventing the accretion of hydrogen and helium onto the solid core. The existence of Jupiter in our solar system can therefore be used to infer constraints on dark matter with relatively strong interaction cross sections. We derive novel constraints on the cross section for both spin-dependent and spin-independent dark matter. We highlight the possibility of a positive detection using future observations by JWST, which could reveal strongly varying planet morpholoiges close to our Galactic Center.

Double polarized deuteron–deuteron scattering and test of T-invariance

A component of the total cross section of the deuteron-deuteron interaction connected with the vector polarized ([Formula: see text]) one initial deuteron and tensor polarized ([Formula: see text]) another one constitutes a null-test signal of the T-invariance violation but P-parity conservation. The energy dependence of this signal is calculated here at beam kinetic energies per nucleon of 0.1–1[Formula: see text]GeV within the Glauber spin-dependent theory of multiple scattering in the S-wave approximation for the deuteron wave function.

Solar neutrinos in cryogenic detectors

Coherent elastic neutrino-nucleus scattering (CEνNS) poses an irreducible background in the search for dark matter-nucleus elastic scatterings, which is commonly known as the neutrino floor. As direct dark matter search experiments keep improving their sensitivity into so far unexplored regions, they face the challenge of approaching this neutrino floor. A precise description of the CEνNS signal is therefore crucial for the description of backgrounds for future DM searches. In this work we discuss the scenario of detecting neutrinos in low-threshold, high-exposure cryogenic solid state experiments optimized for the search of low-mass dark matter. The energy range considered is completely dominated by solar neutrinos. In absence of any dark matter events, we treat solar neutrinos as the main signal of interest. We show that sensitivity to the flux of neutrinos from different production mechanisms can be achieved. In particular we investigate the sensitivity to the flux of pp and 7Be neutrinos, as well as CNO neutrinos. Furthermore, we investigate the sensitivity to dark matter signals in the presence of a solar neutrino background for different experimental scenarios, which are defined by three parameters: the target material, the energy threshold and the exposure. We show that experiments with thresholds of O(eV) and exposures of O(tonne-years), using CaWO4 or Al2O3 targets, have discovery potential for dark matter interaction cross sections in the neutrino floor.

Phonon Drag Contribution to Thermopower for a Heated Metal Nanoisland on a Semiconductor Substrate.

The possible contribution of phonon drag effect to the thermoelectrically sustained potential of a heated nanoisland on a semiconductor surface was estimated in a first principal consideration. We regarded electrons and phonons as interacting particles, and the interaction cross-section was derived from the basic theory of semiconductors. The solution of the equation of motion for average electrons under the simultaneous action of phonon drag and electric field gave the distributions of phonon flux, density of charge carriers and electric potential. Dimensional suppression of thermal conductance and electron-phonon interaction were accounted for but found to be less effective than expected. The developed model predicts the formation of a layer with a high density of charge carriers that is practically independent of the concentration of dopant ions. This layer can effectively intercept the phonon flow propagating from the heated nanoisland. The resulting thermoEMF can have sufficient magnitudes to explain the low-voltage electron emission capability of nanoisland films of metals and sp2-bonded carbon, previously studied by our group. The phenomenon predicted by the model can be used in thermoelectric converters with untypical parameters or in systems for local cooling.

Observation of molecular resonant double-core excitation driven by intense X-ray pulses

The ultrashort and intense pulses of X-rays produced at X-ray free electron lasers (XFELs) have enabled unique experiments on the atomic level structure and dynamics of matter, with time-resolved studies permitted in the femto- and attosecond regimes. To fully exploit them, it is paramount to obtain a comprehensive understanding of the complex nonlinear interactions that can occur at such extreme X-ray intensities. Herein, we report on the experimental observation of a resonant double-core excitation scheme in N2, where two 1σ core-level electrons are resonantly promoted to unoccupied 1πg*\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1{\\pi }_{g}^{* }$$\\end{document} molecular orbitals by a single few-femtosecond broad-bandwidth XFEL pulse. The production of these neutral two-site double core hole states is evidenced through their characteristic decay channels, which are observed in good agreement with high-level theoretical calculations. Such multi-core excitation schemes, benefiting from the high interaction cross sections and state- and site-selective nature of resonant X-ray interactions, should be generally accessible in XFEL irradiated molecules, and provide interesting opportunities for chemical analysis and for monitoring ultrafast dynamic processes.

Gamma absorption and radiation shielding properties of apatite-wollastonite containing SiO2, Fe2O3, and TiO2

This research presents the gamma interaction parameters of glass-ceramics with the apatite-wollastonite (AW) crystal structure within the SiO2–CaO–Al2O3–MgO–P2O5–CaF2 glass (AW) doped with 10% SiO2 (AW-10Si), Fe2O3 (AW-10Fe), and TiO2 (AW-10Ti) by weight. The density of the glass ceramics was determined based on the Archimedes method while the mass attenuation coefficients (MACs) of the glasses were estimated using the PHITS simulation code for gamma photons within the 15 keV-15MeV energies. The obtained densities of AW, AW-10Si, AW-10Ti, and AW-10Fe are 2.90, 2.92, 2.91, and 3.05 g/cm3, respectively. The linear attenuation coefficients of the glasses followed the order LACAW<LACAW−10Si<LACAW−10Ti<LACAW−10Fe. The addition of the metal oxides improves the attenuation coefficients of AW. A gradual increase in the HVLs was observed as the glass density decreased. AW-10Fe has the best photon absorption and scattering interaction cross-sections among the investigated glasses. This study showed that AW-x glasses are nontoxic, cheaper, environmentally friendly, and effective shields compared to some commercial and recently researched shielding glasses.

Synthesis and characterization of metakaolin-based geopolymers doped with CRT waste glass for radiation shielding applications

This study presents the influence of CRT glass on the gamma-ray interaction processes in metakaolin-based geopolymers. Four batches of G-CRT composites (namely, G, G-10CRT, G-20CRT, and G-30CRT, which represent geopolymer (G) samples doped with 0, 10, 20, and 30 wt% of CRT glass) were prepared using the cold hydrostatic press method. The mass attenuation coefficients of the prepared C-xCRT samples were computed using XCOM and FLUKA simulations for photons within the energy range of 15 keV–15 MeV. The density of the pristine geopolymer increased from about 1.86 g/cm3 to 2.09, 2.26, and 2.34 g/cm3 for G-10CRT, G-20CRT, and G-30CRT, respectively. The photon mass and linear attenuation coefficients of the geopolymers increased with CRT glass concentration. The half-value layer and mean free path were within the ranges 0.070–18.079 cm and 0.101–26.083 cm for G; 0.036–15.110 cm and 0.052–21.799 cm for G-10CRT; 0.024–13.197 cm and 0.014–19.039 cm for G-20CRT; and 0.018–12.074 and 0.026–17.419 cm for G-30CRT. The G-30CRT had the best gamma attenuating prowess in contrast to other G-xCRT. CRT-rich G-xCRT had a higher effective atomic number. For 10 mm thick geopolymer, the absorbed dose rates were 0.211 μR/h, 0.66 μR/h, 1.11 μR/h, and 1.55 μR/h for G, G-10CRT, G-20CRT, and G-30CRT, respectively, for 100 keV photons. The introduction of CRT glass into the geopolymer matrix improved their photon interaction cross-section. The geopolymers showed outstanding photon interaction ability compared to ordinary concrete and some shielding glasses at low photon energies. The CRT glass-doped geopolymer samples are useful for preparing radiation shielding concrete.