Electron Energy Spectrum Research Articles (Page 1)

We experimentally demonstrate the possibility of control of electron dynamics during above-threshold ionization (ATI) of argon provided by a moderately strong single-cycle terahertz (THz) field with vector potential amplitude comparable to that of the ionizing near-infrared pulse. The maximum photoelectron energy in ATI spectra, the energy distance between the ATI peaks, as well as the total electron yield, are determined by the THz field vector potential, which varies with the time delay between the ionizing and the THz pulse. Dependence of electron energy spectra on the delay between the pulses is analyzed using the improved strong-field approximation and classical electron trajectories. This information can be used for precise THz pulse characterization.

This study explores the electronic energy spectrum of β-Ga2O3 nanostructures doped with Fe and N atoms using first-principles density functional methods. The findings reveal that the simultaneous doping of Fe and N provides new pathways for tailoring the position of acceptor energy levels in films and clusters, enhancing their suitability for electronic applications. Notably, the energy states vary significantly between confined clusters and thin films, highlighting distinct distribution patterns and doping efficiency depending on impurity substitution sites.

Abstract Whistler‐mode waves play a crucial role in shaping magnetospheric electron dynamics. Using Juno's observations, we investigate these waves in Jupiter's post‐midnight‐to‐dawn magnetosphere, spanning 20–80 Jupiter radii. Our survey reveals that whistler‐mode waves predominantly occur in the lobes, while the magnetodisk remains largely devoid of such waves. Simultaneous electron measurements from JADE‐E, combined with dispersion relation analysis, indicate that these waves are likely driven by a mono‐directional electron population between 0.1 and 10 keV propagating anti‐Jupiter‐ward. Further controlled studies show that a local flux minimum at 0.3 keV in the electron energy spectrum, which is commonly detected during whistler‐mode waves, is critical for wave growth. Based on their direction of motion, we suggest that these mono‐directional electrons and the whistler‐mode waves they generate are related to magnetosphere‐ionosphere coupling. Our findings offer new insights into the interplay between whistler‐mode waves and electrons in Jupiter's magnetosphere.

We investigate the electronic properties of atomic chains placed on group-14 two-dimensional materials, Xenes, by analyzing the local electronic properties. Our results show that the hybridization between the chain and the substrate leads to significant modifications in the local density of states at each chain site, including peak splitting, broadening, and asymmetry. These effects are particularly pronounced for plumbene. Owing to the substrate's V-shaped-like density of states, the chains exhibit strong localization effects and significant intensity variations in the electronic energy spectrum. In addition the present analysis reveals the emergence of charge density waves in atomic chains, for which the appearance and stability conditions are identified and provided. The charge density waves are more pronounced and stabilized by a specific electronic spectrum of Xenes, allowing them to penetrate deeper into the chain interior. Our findings contribute to the broader understanding of the interaction between one-dimensional chains and two-dimensional Xene materials, which have significant implications for developing advanced hybrid nanostructures and next generation electronic devices.

We present a Geant4-based simulation study of the electromagnetic sampling calorimeter (ECAL) foreseen in the LUXE experiment. The ECAL will enable precise measurement of the number and energy spectrum of positrons and electrons. The electromagnetic shower response, energy resolution, and linearity-properties that are essential for physics research-are studied. The Geant4 simulation model provides a good description of the data from the literature, and the stochastic energy resolution is comparable to the state-of-the-art resolution for a Si-W calorimeter. The simulated ECAL model consists of layers of solid-state sensors interspersed between tungsten plates, with the sensors divided into pads. The advantage of these detectors is their high active layer density, which facilitates the construction of more compact devices. A detailed description of the sensor response using MC simulations is fundamental to detector design and predicting energy measurement performance. We collected simulated data using electron beams in the energy range of 2 to 18 GeV, with a step of 2 GeV. The signal size distribution measured in the test beam campaign is well reproduced by the Geant4 simulation, confirming the accuracy of the simulation approach. The analysis described in this paper focuses on electromagnetic shower reconstruction and characterizes the ECAL response to electrons in terms of energy resolution and linearity.

We demonstrated a stable and efficient field electron emission from vertically aligned graphene edges at the apex of the graphitized pencil lead (PL). We found that the electron emission pattern from PL observed with Field Emission Microscope (FEM) was dominated by the “dragonfly patterns” that are characteristic of the graphene edge, clearly suggesting the presence of the graphene edges with nearly vertical alignment at the apex of PL. A large enough emission current was found at the relatively small macroscopic electric field of several V/µm, showing the efficient field enhancement at each graphene flake. The energy spectrum of the emitted electron from PL was slightly broader than that of metals, reflecting the characteristic DOS shape of the π-bands of graphene, and this result is also supported by the recursion-transfer-matrix (RTM) simulations of field emission. A large amount of chemically stable emission sites due to graphene at the apex of PL leads to a large and stable emission current, which was also stable even at high-pressure environments up to 10− 4 Pa of N2. Therefore, the graphitized PL can be utilized as a low-cost electron emitter with high performance. At the same time, it can also be used for specimens for fundamental investigations of graphene edges.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-11895-x.

High energy muons, due to their unique ability to penetrate deeply into matter, can enable radiography of structures that cannot be probed by other forms of radiation. Current terrestrial sources of muons require conventional GeV-TeV particle accelerators which are hundreds to thousands of meters in size. Laser wakefield acceleration (LWFA) can achieve acceleration gradients of two-to-three orders of magnitude greater than conventional accelerators, thus shrinking the accelerator to a number of meters. We propose a concept for a compact muon source based on the first self-consistent PIC simulations of an all optical LWFA that uses a guiding channel to achieve electron energies of 100 GeV in a distance of 6m with a driving laser energy of 300 J in a single stage. From the resulting electron energy spectrum we estimate muon production for this source. We show that this accelerator, coupled with high average power laser driver technology, provides the basis for a high energy and high flux muon source.

Abstract If neutrinoless double beta decay is discovered, the next natural step would be understanding the lepton number violating physics responsible for it. Several alternatives exist beyond the exchange of light neutrinos. Some of these mechanisms can be distinguished by measuring phase-space observables, namely the opening angle cos θ among the two decay electrons, and the electron energy spectra, T 1 and T 2. In this work, we study the statistical accuracy and precision in measuring these kinematic observables in a future xenon gas detector with the added capability to precisely locate the decay vertex. For realistic detector conditions (a gas pressure of 10 bar and spatial resolution of 4 mm), we find that the average $$ \overline{\cos\ \theta } $$ cos θ ¯ and $$ \overline{T_1} $$ T 1 ¯ values can be reconstructed with a precision of 0.19 and 110 keV, respectively, assuming that only 10 neutrinoless double beta decay events are detected.

Seeking for a high-gain fusion scheme is a hot issue in inertial confinement fusion community, especially after the successful fusion ignition at National Ignition Facility. Fast ignition provides an alternative due to its potential to reduce the energy of driven lasers and achieve higher target gain, whose key step is efficiently generating fast electron beam using picosecond lasers. The properties of the electron beam, such as energy spectra, determine heating efficiency and neutron yield. In this paper, with two-dimensional particle-in-cell simulations, we studied how the dual-color lasers affect the fast electron generation. We find that the energy transfer ratio from laser to fast electrons would significantly increase, and the fast electron energy spectra would be adjusted in the dual-color injecting scheme, where an extra weak low-frequency laser is injected with the main pulse. These phenomena are attributed to the longitudinal electric field modulation in the relatively low-density region and relativistic electromagnetically induced transparency (EIT) process in microchannels formed in the over-dense region. Our results can be applied to fast ignition schemes and applications based on relativistic electron generation with different pulses.

In this study, the thermodynamic properties of a two-dimensional Gaussian quantum dot with a repulsive impurity are investigated theoretically. In the framework of the effective mass approximation, wave functions and corresponding energy levels are obtained by using the two-dimensional diagonalization method for solving the Schrödinger equation, and these are used to calculate the canonical partition function. Numerical results show that the electronic energy spectrum and consequently the thermodynamic properties are significantly affected by the parameters defining the effective confinement potential and the impurity position. Furthermore, it was observed that the Schottky-like anomaly observed in the specific heat at the low-temperature limit disappeared with a decrease in the strength of the repulsive impurity potential for the impurity positioned at the center.

Soybean β-conglycinin-debranched starch flexible nano-conjugates: Focus on formation mechanism and physicochemical characteristics.

Purpose Preserving the integrity of the genome is critical to healthy cellular growth and development. Under normal circumstances, the eukaryotic mismatch repair (MMR) machinery is effective at detecting DNA polymerase errors and maintaining the fidelity of the genome. However, cells with inactivated MMR machinery are prone to the accumulation of mutations and tumorigenesis. This study explores the theoretical potential of rhodium-99- and iodine-123-labeled DNA metalloinsertors as Auger electron-emitting radiotherapeutics for cancers characterized by MMR deficiency. Materials and methods A Monte Carlo code was developed in MATLAB® to obtain Auger electron energy spectra for 99Rh and 123I. Using Geant4 track structure simulations, we determined the difference in effectiveness of these two Auger electron-emitting radionuclides in direct damage to DNA and the ability to produce double strand break damage (dsb) to the DNA comparing two different constructors ‘G4EmDNAPhysics_option2’ and ‘G4EmDNAPhysics_option4’. Results Differences in the Auger electron emission spectra of 99Rh and 123I arise from their electronic structure: 123I favors more complex cascades and ultra-low-energy electrons, while 99Rh produces electrons with energies more suited to DNA damage. Despite similar total electron yields, the emissions of 99Rh are more effective at causing dsb (0.71 vs. 0.60 dsb/decay for 99Rh and 123I, respectively, using constructor ‘G4EmDNAPhysics_option2’ and 0.81 dsb/decay for 99Rh vs. 0.71 dsb/decay for 123I when using ‘G4EmDNAPhysics_option4’. Conclusion This theoretical study leverages both simulation and comparative analyses to identify 99Rh as a promising Auger electron-emitting nuclide for radiotheranostics, as it offers superior DNA damage efficacy compared to 123I.

The spin-polarized electronic energy spectra of the ZnSeS solid solution were obtained based on calculations for the supercell containing 64 atoms. The electronic properties of the materials based on the two supercells, namely Zn31Cr1Se8S24 and Zn31Cr1Se24S8, were calculated, where Cr replaces the Zn atom. The calculation results reveal that the both materials are semiconductors for the spin down electronic states. For the opposite spin momentum of electrons both materials show the matallic states. For both materials, a significant effect of the substitutional Cr impurity on their electronic and magnetic properties has been established. Both materials investigated here are semimetals, so they are promising materials for spin electronics.

Aims. We present ten solar energetic electron (SEE) events measured by Wind/3DP at ∼1 to 200 keV with a bump break in the electron peak flux versus energy spectrum. We examined their acceleration sources and/or processes at the Sun. Methods. We assumed that these bump SEE events consist of two electron populations: a primary population (described by the pan-spectrum (PS) function), and a bump population (described by the Gaussian function), which dominate at low and high energies, respectively. We constructed two formulae to fit the SEE energy spectrum by multiplying a PS function with a natural exponential form of the Gaussian function (i.e., the MUL formula) and by adding a PS function with a Gaussian function (i.e., the ADD formula). Results. The fitting results suggest that the MUL fitting can reflect the physical nature in the formation of these bump events. For the primary electron population, the MUL fitting obtains an upward-bending double power-law spectrum for event 10 with a spectral index of 3.58 (1.74) at energies below (above) ∼4.6 keV, and a single power-law spectrum for the other nine events with a median spectral index of 2.52+0.29−0.25. For the bump electron population, the fitted center energy has a median value of 59.1−3.2+18.1 keV. For the events associated with soft X-ray flares (west limb coronal mass ejections), the flare class (angular width of the coronal mass ejection) is positively correlated with the estimated electron number of the power-law population Npl and of the bump population Nbp (the number ratio Nbp/Npl at 10–400 keV). Conclusions. These results indicate that for these bump SEE events, the power-law electron population can be produced by some flare-related processes that occur high in the corona, while the bump population can be accelerated by some processes related to coronal mass ejections that act on the power-law population. The bump-like spectrum might also be the intermediate spectrum during the evolution from single power-law to downward-bending double power-law.

We present a simulation configuration for the electron beam profile consistent with experiments on the linear accelerator UERL-10-15S2, focusing on determining electron energy and beam size. Two essential aspects of the electron beam described in the simulation configuration are the initial energy distribution and the initial beam size with the flux distribution. Notably, we introduce a new mathematical function by modifying the approximated Landau distribution. This new function offers a better fit than our previous mathematical function and, more importantly, accurately reflects the physical nature of the energy spectrum of electrons passing through a thin layer of matter. Using this configuration, we have simulated the irradiation of zeolite ETS-10 by the electron beam. This irradiated simulation was set up with various electron energy distributions, yielding results on the dose rate distribution (2D dose map) and the mean absolute percentage deviation of the absorbed dose rate within the irradiated titanosilicate. With the improvements in this paper, we have provided a solution to enhance the linear accelerator’s application in scientific research besides conventional industrial irradiation applications. Published by the American Physical Society 2025

Abstract The present study examined the structural, electronic, mechanical, thermal and optical properties of the CoVGe half—Heusler compound with GGA-PBE and TB-mBJ exchange correlational potential. These properties were investigated using the full-potential linearized augmented plane wave (FP-LAPW) method, which is associated with the density functional theory (DFT) framework. The density of states (DOS) and band structure were analyzed. The indirect band gaps (Band Transition L→X) of 0.69 eV for GGA-PBE and 0.95 eV for TB-mBJ approaches are obtained, indicating the semiconducting nature of the material. The elastic and thermodynamic properties confirm its mechanical and thermal stability. The Debye temperature ( θ D ) of 589 K is obtained, indicating stronger atomic bonding and higher vibrational frequencies within a material. The various optical properties such as dielectric function, refractive index, extinction coefficient, optical conductivity, absorption coefficient, electron-energy loss spectrum, and reflectivity were investigated. The research findings revealed that CoVGe half—Heusler compound is more appropriate candidate for optoelectronic energy applications.

Abstract We study the Hofstadter butterfly spectrum in (1 + 3 + 1) chirally twisted multilayer graphene (CTMLG) subject to perpendicular magnetic field and light with different polarizations. We focus on the interplay between twist angles and light-induced effects. In equilibrium, we examine symmetric ( θ 1 = θ 2 ) and asymmetric ( θ 1 ≠ θ 2 ) configurations. Our results show that asymmetric configurations cause distinct effects in the electronic energy spectrum. However, the unique symmetry of the system ensures that the spectra remain identical when the twist angles are interchanged. This highlights the role of interlayer coupling in shaping the electronic structure of CTMLG. We then explored the effects of external periodic perturbations, such as circularly polarized light (CPL) and waveguide-generated linearly polarized light (WGL). CPL breaks chiral symmetry, creating a gap that distorts the Hofstadter spectrum. These distortions are more pronounced for asymmetric twist configurations. In contrast, WGL preserves chiral symmetry and has a tunable, non-monotonic effect on the bandwidth. This makes WGL a reliable tool for engineering electronic properties. These results demonstrate how (1 + 3 + 1)-CTMLG combines the effects of light-matter interactions with moiré physics. This allows accurate control of the electronic properties and fractal spectra by adjusting external fields and twist angles.

Abstract Using high‐quality electron measurements from Van Allen Probes during October 2013 and March 2019, this study investigates the spatial distribution and geomagnetic dependence of the electron reversed energy spectrum in the Earth's radiation belts. The reversed energy spectrum is primarily observed within the L‐shell range of ∼2.6–5.2, with peak occurrence rates reaching ∼50% at L = ∼4. Occurrence rates are higher in the post‐noon to midnight sectors and lower on the pre‐dawn side. In terms of magnetic latitude (MLAT), the spectrum spans ∼−20°–20°, exhibiting south‐north asymmetry, particularly in the noon and night regions. The characteristic energies defining the spectrum correspond to the flux minimum (Ev) and maximum (Ep), which typically range from ∼100 keV to ∼1 MeV and hundreds of keV–∼2 MeV, respectively, with both Ev and Ep decreasing as L increases. The spectrum is more frequently observed during geomagnetically quiet periods, with maximum occurrence rates exceeding 50%. However, as geomagnetic activity intensifies, the occurrence rates decrease significantly, and the favorable region contracts toward lower L‐shells. Analysis of geomagnetic indices shows that the reversed energy spectrum is more strongly affected by the Dst index than the auroral electrojet (AE) index. This could suggest a more substantial influence of geomagnetic storms than the substorm activity on suppressing the electron reversed energy spectrum. These results improve our understanding of how radiation belt electron dynamics respond to geomagnetic disturbances, emphasizing the interplay between storms, substorms, and wave‐particle interactions in shaping the evolution of the reversed electron energy spectrum.

Leakage accident occurred during the operation of a buried valve blowdown pipe in a natural gas station. After the macroscopic morphology, mechanical properties, chemical composition, metallography, scanning electron microscopy and energy spectrum analysis of the leaking blowdown pipe, it was found that the corrosion perforation was located in the outer wall of the pipe, and the damage of the corrosion layer caused the corrosion components in the saline soil to contact the steel pipe to produce oxygen corrosion. In addition, Cl– ions in the soil played a role in accelerating corrosion, which eventually led to the occurrence of perforation accidents.

Within the framework of the adiabatic approximation, the electron's energy spectrum in a strongly oblate asymmetric ellipsoidal quantum dot, in the presence of an axial magnetic field, has been investigated. It has been shown that in the QD's section plane, for relatively low energy levels, the confining potential of the system can be described within the framework of a two-dimensional asymmetric oscillator. The electron's axial and planar energies have been defined, and the electron's energy dependencies on the geometrical parameters as well as the magnitude of the magnetic field have been studied.