Broad Energy Range Research Articles

Eco-friendly transparent glass prepared from rice straw ash for neutron and charged particle radiation shielding

The current study aimed to fabricate and investigate new glass system incorporating silica from rice straw ash (RSA). The effect of adding different concentrations of bismuth oxide (Bi2O3) on the glass's structure was examined using FTIR. The A.C. conductivity of the prepared glasses over the frequency range (120 Hz − 100 kHz) and the temperature range (300–620 oK) have been measured. Based on its electron density, a substance's electrical conductivity can alter as photon energy increases. For the current investigated glasses, the electron density (Neff) and electrical conductivity relation over the energy range (0.015–10 MeV) were calculated. Glass samples' ability to attenuate radiation such as neutrons, electrons, protons, and alpha particles has been investigated. For neutrons, the effective removal cross-section (∑R, cm−1) and the total macroscopic cross-section (∑T, cm−1) are calculated. For charged particles like protons (H+) and alpha (He2+), SRIM software has been used to determine the glass Mass Stopping Power (MSP) and the Projected Range (PR). For electrons (β−), MSP and the Continuous Stopping Down Approximation (CSPA) were calculated using ESTAR (NIST). On the other hand, Phy X/Zextra software was used to determine glasses effective atomic numbers (Zeff) over a broad energy range. As a result, BSiBi20 glass with the highest Bi2O3 concentrations (20 mol. %) shows superior shielding features for fast neutrons (∑R = 0.128 cm−1) compared to the competitors like ordinary concrete (O.C.). For charged particles, BSiBi20 glass achieves the lowest MSP, CSPA, and the highest Zeff values over the entire energy range. The KERMA (Kinetic Energy Released per unit Mass of the Absorbing material) calculations indicated a significant influence on the elemental composition of the glass system in the intermediate photon energy regime.

New Inogranic Scintillators’ Application in the Electromagnetic Calorimetry in High-Energy Physics

Scintillation crystals Gd3Al2Ga3O12 (GAGG) are an excellent candidate for application in ionizing-radiation detectors because of their high radiation resistance, density and light yield. These crystals can be used in combination with lead tungstate (PbWO4 or PWO) crystals for the development of a new generation of electromagnetic calorimeter with advanced spatial and energy resolutions in a broad energy range. PWO crystals enable the accurate detection of high-energy photons, while GAGG crystals provide the possibility of precisely measuring photon energies, down to a few MeV. Different options for a composite electromagnetic calorimeter based on PWO and GAGG crystals are considered to optimize spatial and energy resolutions in a broad energy range (from 1 MeV to 100 GeV). In particular, different lengths of the GAGG section of the calorimeter are considered, from 0.5 to 10 cm. The separation of signals from photons and hadrons is also taken into consideration through the study of shower shape in the calorimeter. The optimization is based on Geant4 simulations, considering light collection as well as the use of different photodetectors and electronic noise. Simulations are verified with light yield measurements of GAGG samples obtained using radioactive sources and test beam measurements of the prototype of the PWO-based Photon Spectrometer of the ALICE experiment at CERN.

Simulation software of the JUNO experiment

The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose experiment, under construction in southeast China, that is designed to determine the neutrino mass ordering and precisely measure neutrino oscillation parameters. Monte Carlo simulation plays an important role for JUNO detector design, detector commissioning, offline data processing, and physics processing. The JUNO experiment has the world’s largest liquid scintillator detector instrumented with many thousands of PMTs. The broad energy range of interest, long lifetime, and the large scale present data processing challenges across all areas. This paper describes the JUNO simulation software, highlighting the challenges of JUNO simulation and solutions to meet these challenges, including such issues as support for time-correlated analysis, event mixing, event correlation and handling the simulation of many millions of optical photons.

From phonons to the thermal properties of complex thermoelectric crystals: The case of type-I clathrates

Exploiting the structural complexity of crystals at the scale of their unit cell is a well-established strategy in the search for efficient materials for energy conversion, which aims at disentangling and separately engineering heat and charge transport. This route has resulted in the discovery of clathrates with exceptionally low lattice thermal conductivity but essentially unaffected and tunable electronic properties. Although their thermal conductivity behaves similarly to the one of glasses, its origin is fundamentally different. Indeed, phonons with long lifetime were observed over the whole Brillouin zone, thus excluding an interpretation in terms of a reduced mean free path. However, the energy–momentum phase space which contains these heat carrying phonons is capped by a dense spectrum of diffusive modes. The thermal properties of clathrates can therefore be split in two parts: a narrow low energy regime that contains propagative modes which dominate the thermal transport, and a broad high energy range consisting of diffusive modes that dominate the heat capacity. Based on this understanding, a simple phenomenological model, based on a basic description in terms of Debye and Einstein modes, is derived that allows for a meaningful interpretation of experimental data, by providing a connection to the underlying microscopic origin. Finally, the criteria for determining the minimum lattice thermal conductivity are redefined and strategies for decreasing the lattice conductivity are proposed.

A novel multi-radionuclide imaging method based on mechanical collimated Compton camera

Simultaneous imaging of multiple radionuclides can improve the accuracy of clinical diagnosis and therapy, and has great significance for clinical and molecular applications. However, the photon energies produced by radionuclides cover a broad energy range from a few keV to several MeV, and simultaneously imaging multiple radionuclides in such a broad energy range is a challenge. This study proposes a novel and easy-to-implement multi-radionuclide imaging method based on the mechanical collimated Compton camera (MCCC) to achieve multi-radionuclide imaging in a broad energy range. 18F and 99mTc point source imaging experiments were conducted using MCCC, at a distance of 10 cm from the radioactive source, the radial full width at half maximum of 18F and 99mTc point source imaging results were evaluated to be 7.3 mm and 4.5 mm. In addition, we demonstrated the feasibility of using MCCC to simultaneously imaged 18F and 99mTc in mouse phantom experiments at the heart and bladder sites and the bladder and kidneys sites, the reconstructed high radioactivity area in the 3D imaging results was basically consistent with the set radioactivity distribution. Then, Monte Carlo simulations of other types of radionuclides were performed with reference to phantom experiment at the bladder and kidneys sites. Simulation results shown the promising potential of the proposed method for imaging multiple radionuclides in a broad energy range.

First-principles calculations to investigate optical properties of topological semimetal MX compounds (M = Ti, Zr, Hf and X = S, Se, Te)

In this study, the first-principles calculation was used to explore the optical properties of MX (M = Ti, Zr, Hf, and X = S, Se, Te) compounds in light of their newly discovered unique electronic properties over a broad energy range. The influence of each orbital (s, p, and d) was studied by comparing the imaginary and real spectra of dielectric functions with the electronic properties of these compounds. The d-orbital of transition metals has a major impact on the absorption performance of all these compounds. In negative regions of the real spectra, a very high intensity of reflectivity was observed. The high peaks of energy loss along x, y, and z components are linked to plasmons and in good agreement with real (Reii (ω) =0) and imaginary (Imgii (ω)≈0) spectra values. For transition metal M (i.e., Ti, Zr, and Hf), when the X element is changed from S to Te, a significant shift from higher to lower energy has been observed in the imaginary, real, reflectivity, and energy loss spectra of the x, y, and z components, respectively.

Printable Perovskite Diodes for Broad-Spectrum Multienergy X-Ray Detection.

Multienergy X-ray detection is critical to effectively differentiate materials in a variety of diagnostic radiology and nondestructive testing applications. Silicon and selenium X-ray detectors are the most common for multienergy detection; however, these present poor energy discrimination across the broad X-ray spectrum and exhibit limited spatial resolution due to the high thicknesses required for radiation attenuation. Here, an X-ray detector based on solution-processed thin-film metal halide perovskite that overcomes these challenges is introduced. By harnessing an optimized n-i-p diode configuration, operation is achieved across a broad range of soft and hard X-ray energies stemming from 0.1 to 10's of keV. Through detailed experimental and simulation work, it is shown that optimized Cs0.1 FA0.9 PbI3 perovskites effectively attenuate soft and hard X-rays, while also possessing excellent electrical properties to result in X-ray detectors with high sensitivity factors that exceed 5 × 103 and 6 × 104 µC Gy-1 cm-2 within soft and hard X-ray regimes, respectively. Harnessing the solution-processable nature of the perovskites, roll-to-roll printable X-ray detectors on flexible substrates are also demonstrated.

Bioluminescent eddies of the World Ocean.

Mesoscale eddies of the ocean (with a characteristic diameter of about one hundred km and a life time span of about several weeks) are habitats of plankton organisms, many of which are bioluminescent. The spatial heterogeneity of bioluminescence of the upper mixed layer associated with the impact of mesoscale eddies is poorly studied. The 45-year historical data set was retrieved, in order to select the bathy-photometric surveys carried out in the form of station grids and transects across eddies. Data from 71 expeditions deployed in 1966-2022 to the Atlantic Ocean, Indian Ocean and Mediterranean Sea basin were analyzed, in order for the spatial heterogeneity of bioluminescent fields to be elucidated across eddy fields. The stimulated bioluminescence intensity was characterized by the bioluminescent potential, which represented the maximal amount of radiant energy emitted in a given volume of water by bioluminescent organisms. The normalized bioluminescent potential over oceanographic station grids exhibited correlation with the eddy kinetic energy and zooplankton biomass (r =0.8, at p=0.001 and r =0.7, at p=0.05, respectively), in a broad range of energy and bioluminescence units (0.02-0.2 m2 s-2 ; 0.4-92.0*10-8 W cm-2 L-1 , respectively). Overall, estimates of bioluminescent potential variability on the mesoscale contribute to the assessment of the multiple-scale variation of the bioluminescent field of the World Ocean.

Investigation of structural, opto-electronic, mechanical and thermoelectric properties of Rb-based fluoro-perovskites RbXF3 (X = Rh, Os, Ir) via first-principles calculations

A theoretical study on Rb-based fluorperovskites RbXF3(X = Rh, Os, Ir) is performed for the first time to explore their structural, electronic, optical and thermoelectric properties. The compounds are stable in cubic perovskite type structures with lattice spacing in the range of 4.30 4.35 Å. RbRhF3 and RbIrF3 exhibit half-metallic character with indirect band gaps of 4.2 eV and 2.1 eV, respectively, at R-Γ, whereas RbOsF3 possesses entirely semiconducting nature. The calculation of elastic properties revealed that under study compounds are mechanically stable, having ionic bonding. Furthermore, all compounds show ductile nature. Optical properties were also calculated in the broad energy range 0–40 eV.

A ReaxFF molecular dynamics and RRKM ab initio based study on degradation of indene

The degradation of indene is investigated using molecular dynamics (MD) with the ReaxFF force field and RRKM theory. Microcanonical rate constants are obtained over a broad energy range (8–25 eV). There is agreement between the results of the molecular dynamics and RRKM calculations at the lower energies, while the molecular dynamics rate constants are larger at the higher energies. At the lower energies there is also agreement with values obtained by using expressions for photodegradation of polyaromatic hydrocarbons from the literature. Values from those expressions however increase even faster with energy than our molecular dynamics rate constants do. At the same time those values are lower than an experimental result at 6.4 eV. This suggests that astrochemical models employing those values may result in unreliable polycyclic aromatic hydrocarbons abundances.

Exciton Ground State Fine Structure and Excited States Landscape in Layered Halide Perovskites from Combined BSE Simulations and Symmetry Analysis

AbstractLayered halide perovskites are solution‐processed natural heterostructures where quantum and dielectric confinement down to the nanoscale strongly influence the optical properties, leading to stabilization of bound excitons. Detailed understanding of the exciton properties is crucial to boost the exploitation of these materials in energy conversion and light emission applications, with on‐going debate related to the energy order of the four components of the most stable exciton. To provide theoretical feedback and solve among contrasting literature reports, this work performs ab initio solution of the Bethe–Salpeter equation (BSE) for symmetrized reference Cs2PbX4 (X = I and Br) models, with detailed interpretation of the spectroscopic observables based on group‐theory analysis. Simulations predict the following Edark < Ein‐plane < Eout‐of‐plane fine‐structure assignment, consistent with recent magneto‐absorption experiments and obtain similar increase in dark/bright splitting when going from lead‐iodide to a lead‐bromide composition as found experimentally. The authors further suggest that polar distortions may lead to stabilization of the in‐plane component and end‐up in a bright lowest exciton component, discuss exciton landscape over a broad energy range and clarify the exciton spin‐character, when large spin‐orbit coupling is in play, to rationalize the potential of halide perovskites as triplet sensitizers in combination with organic dyes.

B10 + α reactions at low energies

Nucleosynthesis in primordial stellar environments may lead to a substantial production of $^{10}\mathrm{B}$ isotopes, which either are converted by the $^{10}\mathrm{B}(p,\ensuremath{\alpha})^{7}\mathrm{Be}$ reaction to $^{7}\mathrm{Be}$ or processed further by $^{10}\mathrm{B}+\ensuremath{\alpha}$ reactions towards the carbon, nitrogen, and oxygen range. This paper focuses on low energy studies of the $^{10}\mathrm{B}(\ensuremath{\alpha},p)^{13}\mathrm{C}$ and $^{10}\mathrm{B}(\ensuremath{\alpha},d)^{12}\mathrm{C}$ reactions to determine the low energy cross section and the reaction rates in stellar environments using $R$-matrix analysis techniques. The experimental results cover a broad energy range, from 0.21 MeV up to 1.4 MeV in the center of mass frame, extending down to the Gamow energy range. A substantial increase in the reaction rate compared to previous predictions is found, due to the identification of near threshold $\ensuremath{\alpha}$-cluster resonance structures.

Beam Energy Dependence of the Linear and Mode-Coupled Flow Harmonics Using the a Multi-Phase Transport Model

In the framework of the A Multi-Phase Transport (AMPT) model, the multi-particle azimuthal cumulant method is used to calculate the linear and mode-coupled contributions to the quadrangular flow harmonic (v4) and the mode-coupled response coefficient as functions of centrality in Au+Au collisions at sNN = 200, 39, 27 and 19.6 GeV. This study indicates that the linear and mode-coupled contributions to v4 are sensitive to beam energy change. Nevertheless, the correlations between different-order flow symmetry planes and the mode-coupled response coefficients show weak beam energy dependence. In addition, the presented results suggest that the experimental measurements that span a broad range of beam energies can be an additional constraint for the theoretical model calculations.

Structure and gamma-ray attenuation capabilities for eco-friendly transparent glass system prepared from rice straw ash

The current study investigates the physical structural and radiation shielding capabilities of a newly developed glass system incorporating silica extracted from rice straw ash (RSA). The purity and chemical composition of the silica are determined using XRF. XRD confirms the amorphous character of the synthesized glass. Moreover, molar volume, optical parameters, and density will be investigated. Gamma (γ)-rays shielding parameters like half-value layer, mass attenuation coefficient, the effective atomic number, and the mean free path are experimentally measured across a broad range of gamma-ray energies (81 keV–1408 keV) emitted from 152Eu, 133Ba, 137Cs, and 60Co radioactive isotopes. The exposure buildup factor will be evaluated with the geometric progression fitting approximation. In addition, Phy-X/PSD software is used to calculate theoretically the former shielding parameters. A good agreement between theoretical and experimental values has been revealed. Finally, a comparison was made to investigate the potential use of our glass to replace the common shielding material like concrete (ordinary and hematite-serpenite), commercial glass (RS 253), and the newly developed Ag2O doped boro-tellurite glass. The newly prepared glass has higher MAC, Zeff values and lowered HVL and MFP values. These properties make our prepared glass system superior in terms of shielding from γ-rays.

Characterizing initial- and final-state effects of relativistic nuclear collisions

The Multi-Phase Transport model (AMPT) is used to study the final state effects on the Symmetric Correlations (SC), Asymmetric Correlations (ASC), Normalized Symmetric Correlations (NSC), and Normalized Asymmetric Correlations (NASC) in Au+Au collisions at 200~GeV. The correlators' sensitivity to non-flow effects associated with long- and short-range non-flow correlations are also discussed using the HIJING model. The results indicate that SC, ASC, NSC, and NASC can give accompanying constraints for initial and final state effects. In addition, conducting further detailed experimental measurements spanning a broad range of collision systems and beam energies will serve as an additional constraint for the theoretical models' calculations.

Stable attosecond beamline equipped with high resolution electron and XUV spectrometer based on high-harmonics generation

We present a high-resolution and delay-stabilized setup for attosecond spectroscopy based on high-order harmonic generation from the intense laser passing through a differential gas cell. It shows the ability to generate the tunable photons from VUV to Soft X-ray (20–180 eV) at low backing pressure of target gas. This atto-beamline consists of an HHG source, electron and XUV spectrometers, and an active stabilization system. The measurements show it can be stabilized to sub-20 as in hours, together with a home-built XUV spectrometer with an energy resolution better than E/ΔE≥1200 in the wavelength range of 5–25 nm. We demonstrated its applications for producing the narrowband XUV source, extending the cutoff energy of HHG, and performing RABBITT measurements, particularly for investigating the excitation and ionization dynamics of atoms and molecules in a broad energy range by measuring the electrons and photons with attosecond temporal resolution.

Superhydrophobic and Conductive Foams with Antifouling and Oil–Water Separation Properties

Hybrid organic-inorganic materials are attracting enormous interest in materials science due to the combination of multiple advantageous properties of both organic and inorganic components. Taking advantage of a simple, scalable, solvent-free hard-sacrificial method, we report the successful fabrication of three-dimensional hybrid porous foams by integrating two types of fillers into a poly(dimethylsiloxane) (PDMS) framework. These fillers consist of hydrophobic electrically conductive graphene (GR) nanoplatelets and hydrophobic bactericidal copper (Cu) microparticles. The fillers were utilized to create the hierarchical rough structure with low-surface-energy properties on the PDMS foam surfaces, leading to remarkable superhydrophobicity/superoleophilicity with contact angles of 158 and 0° for water and oil, respectively. The three-dimensional interconnected porous foam structures facilitated high oil adsorption capacity and excellent reusability as well as highly efficient oil/organic solvent-water separation in turbulent, corrosive, and saline environments. Moreover, the introduction of the fillers led to a significant improvement in the electrical conductivity and biofouling resistance (vs whole blood, fibrinogen, platelet cells, and Escherichia coli) of the foams. We envision that the developed composite strategy will pave a facile, scalable, and effective way for fabricating novel multifunctional hybrid materials with ideal properties that may find potential use in a broad range of biomedical, energy, and environmental applications.

Cosmogenic activation of sodium iodide

The production of radioactive isotopes by interactions of cosmic-ray particles with sodium iodide (NaI) crystals can produce radioactive backgrounds in detectors used to search for rare events. Through controlled irradiation of NaI crystals with a neutron beam that matches the cosmic-ray neutron spectrum, followed by direct counting and fitting the resulting spectrum across a broad range of energies, we determined the integrated production rate of several long-lived radioisotopes. The measurements were then extrapolated to determine the sea-level cosmogenic neutron activation rate, including the first experimental determination of the tritium production rate: $(80\ifmmode\pm\else\textpm\fi{}21)\text{ }\text{ }\mathrm{atoms}/\mathrm{kg}/\mathrm{day}$. These results will help constrain background estimates and determine the maximum time that NaI-based detectors can remain unshielded above ground before cosmogenic backgrounds impact the sensitivity of next-generation experiments.

Systematic study of global optical model potentials in (d, p) transfer reactions* *Supported by the National Natural Science Foundation of China (12035011, 11975167, 11535004, 11947211, 11905103, 11761161001, 11375086, 11565010, 11881240623, 11961141003), the National Key R&D Program of China (2018YFA0404403, 2016YFE0129300), the Science and Technology Development Fund of Macau (008/2017/AFJ) and the Fundamental Research Funds for the Central Universities (22120200101)

In the T-matrix form of the transfer reaction, the optical model potentials (OMPs) are used to compute the scattering wave function and transition operator. For most cases, the elastic scattering cross sections, normally used to generate the OMPs, are not directly given in the same experiment. Then, the global OMPs, which fit the experimental data over a broad mass and energy range, are widely used in the theoretical calculations. Different sets of global OMPs with different parameter sets can reproduce the scattering cross section equally well within the uncertainty. Here, we apply different global OMPs to calculate the (differential) cross sections of transfer reactions on the target nuclei , , , and at different energies. The results demonstrate that the effects of deuteron and nucleon global OMPs on transfer (differential) cross sections vary with energy and target mass. Furthermore, the influences of the spin-orbit coupling term of deuteron and nucleon global OMPs on the transfer cross sections are not negligible.

Ultrafast hot electron dynamics in plasmonic nanostructures: experiments, modelling, design

Abstract Metallic nanostructures exhibit localized surface plasmons (LSPs), which offer unprecedented opportunities for advanced photonic materials and devices. Following resonant photoexcitation, LSPs quickly dephase, giving rise to a distribution of energetic ‘hot’ electrons in the metal. These out-of-equilibrium carriers undergo ultrafast internal relaxation processes, nowadays pivotal in a variety of applications, from photodetection and sensing to the driving of photochemical reactions and ultrafast all-optical modulation of light. Despite the intense research activity, exploitation of hot carriers for real-world nanophotonic devices remains extremely challenging. This is due to the complexity inherent to hot carrier relaxation phenomena at the nanoscale, involving short-lived out-of-equilibrium electronic states over a very broad range of energies, in interaction with thermal electronic and phononic baths. These issues call for a comprehensive understanding of ultrafast hot electron dynamics in plasmonic nanostructures. This paper aims to review our contribution to the field: starting from the fundamental physics of plasmonic nanostructures, we first describe the experimental techniques used to probe hot electrons; we then introduce a numerical model of ultrafast nanoscale relaxation processes, and present examples in which experiments and modelling are combined, with the aim of designing novel optical functionalities enabled by ultrafast hot-electron dynamics.