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The paper studies the influence of the spectral composition of accelerated radiation on the radiation intensity of a relativistic charged particle based on its equation of motion in the field of the amplitude-modulated electromagnetic wave. Equations are suggested for the phase and phase-angular distributions of the particle radiation. The dependence between the radiation and modulation coefficient are presented herein. [ABSTRACT FROM AUTHOR]

Electromagnetic scattering is a routine tool for rapid, non-contact characterization of particle media. In previous work, the interaction targets of scattering intensity, scattering efficiency, and extinction efficiency of Bessel pincer light-sheet beams were all aimed at dielectric spheres. However, most particles in nature are charged. Considering the boundary condition on a charged sphere, the beam shape coefficients (BSCs) ( p m n , q m n ) of the charged spherical particle illuminated by a Bessel pincer light-sheet beam are obtained. The extinction, scattering, and absorption efficiencies are derived under the generalized Lorenz–Mie theory (GLMT) framework. This study reveals the significant differences in scattering characteristics of Bessel pincer light-sheet beams on a charged particle compared to traditional beams. The simulations show a few apparent differences in the far-field scattering intensity and efficiencies between charged and natural spheres under the influence of dimensionless size parameters. As dimensionless parameters increase, the difference between the charged and neutral spheres decreases. The effects of refractive index and beam parameters on scattering, extinction, and absorption coefficients are different but tend to converge with increasing dimensionless parameters. When applied to charged spheres with different refractive indices, the scattering, extinction, and absorption efficiencies of Bessel pincer light-sheet beams change with variations in surface charge. However, once the surface charge reaches saturation, these efficiencies become stable. This study is significant for understanding optical manipulation and super-resolution imaging in single-molecule microbiology. [ABSTRACT FROM AUTHOR]

The loss of any symmetry in a system leads to quantum problems that are typically very difficult to solve. Such a situation arises for particles with anisotropic mass, like electrons in various semiconductor host materials, where it is known that they may have an anisotropic effective mass. In this work, we consider the quantum problem of a spinless charged particle with anisotropic mass in two dimensions and study the resulting energy and eigenstate spectrum in a uniform constant perpendicular magnetic field when a Landau gauge is adopted. The exact analytic solution to the problem is obtained for arbitrary values of the anisotropic mass using a mathematical technique that relies on the scaling of the original coordinates. The characteristic features of the energy spectrum and corresponding eigenstate wave functions are analyzed. The results of this study are expected to be of interest to quantum Hall effect theory. [ABSTRACT FROM AUTHOR]

A classical theory of radiation from a relativistic charged particle linearly accelerated by a high-intensity laser pulse with modulated polarization is developed via solving the equation of motion of a charge in the electromagnetic wave field. The formulas for calculating the spectral and angular characteristics of radiation, namely, the radiation intensity of a particle and its phase- and phase-angle distributions are obtained. The graphs of dependence of the radiation characteristics on the modulation coefficient are constructed. [ABSTRACT FROM AUTHOR]

This study investigates the nuclear radiation parameters of selected Ti alloys with potential biomedical applications. The compatibility with nuclear radiation is essential for these alloys in biomedical applications. To understand the nuclear radiation compatibility for this selected alloy, the gamma rays, neutrons, and charged particle interaction parameters were estimated using EpiXS, NGCal, ESTAR, and SRIM. The gamma rays, neutrons, and charged particle interaction parameters of selected Ti alloys relative to the cortical bone were studied. The Zeff of selected alloys relative to the cortical bone reaches unity in the lower photon energy region. Similar values of energy absorption buildup factor for selected alloys and cortical bone when the gamma energy region lies between 200 keV and 3 MeV. For neutron interaction at incident energy of thermal neutron at 25.4 meV and fast neutron 4 MeV, significant differences exist between selected alloys and cortical bone. From the estimated data, it is observed that among selected alloys, Ti-6Al-4V and Ti-6Al-4V-2.5Cu are comparable with cortical bone in terms of gamma rays and charged particle interactions. The results indicate that Ti-6Al-4V and Ti-6Al-4V-2.5Cu are the most suitable alloys for biomedical applications such as knee, hip, and elbow joints. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the influence of the angular momentum of the charged particle around non-extremal and extremal charged Taub–NUT black holes on Lyapunov exponent, and find spatial regions where chaos bound is violated. The exponent is determined by the effective potential. When the particle's charge is fixed, circular orbits gradually move away from the event horizons with the angular momentum's increases. We find that the bound is always violated at a certain distance from the horizons when the angular momentum is greater than a certain value. Especially when the black holes' charges are small enough, the Lyapunov exponent's violation always exists for any value of the particle's angular momentum. [ABSTRACT FROM AUTHOR]

Abstract Advanced numerical techniques for solving the relativistic equations of motion for charged particles are provided. A new fourth-order integrator is developed by combining the Taylor series expansion of the numerical angle of relativistic gyration and the fourth-order Runge–Kutta method for integrating the Lorentz factor. The new integrator gives the exact relativistic E-cross-B drift velocity, but has a numerical accuracy much higher than the classic fourth-order Runge–Kutta integrator. Graphical Abstract

Electromagnetic scattering is a routine tool for rapid, non-contact characterization of particle media. In previous work, the interaction targets of scattering intensity, scattering efficiency, and extinction efficiency of Bessel pincer light-sheet beams were all aimed at dielectric spheres. However, most particles in nature are charged. Considering the boundary condition on a charged sphere, the beam shape coefficients (BSCs) (pmn,qmn) of the charged spherical particle illuminated by a Bessel pincer light-sheet beam are obtained. The extinction, scattering, and absorption efficiencies are derived under the generalized Lorenz–Mie theory (GLMT) framework. This study reveals the significant differences in scattering characteristics of Bessel pincer light-sheet beams on a charged particle compared to traditional beams. The simulations show a few apparent differences in the far-field scattering intensity and efficiencies between charged and natural spheres under the influence of dimensionless size parameters. As dimensionless parameters increase, the difference between the charged and neutral spheres decreases. The effects of refractive index and beam parameters on scattering, extinction, and absorption coefficients are different but tend to converge with increasing dimensionless parameters. When applied to charged spheres with different refractive indices, the scattering, extinction, and absorption efficiencies of Bessel pincer light-sheet beams change with variations in surface charge. However, once the surface charge reaches saturation, these efficiencies become stable. This study is significant for understanding optical manipulation and super-resolution imaging in single-molecule microbiology.

Advanced numerical techniques for solving the relativistic equations of motion for charged particles are provided. A new fourth-order integrator is developed by combining the Taylor series expansion of the numerical angle of relativistic gyration and the fourth-order Runge–Kutta method for integrating the Lorentz factor. The new integrator gives the exact relativistic E-cross-B drift velocity, but has a numerical accuracy much higher than the classic fourth-order Runge–Kutta integrator. [ABSTRACT FROM AUTHOR]

Abstract Objective Carbon ion radiotherapy (C-ion RT) for chordomas has been gradually performed in several research centres. This study aimed to systematically review the results of clinical reports from these institutions and to evaluate the safety and efficacy of C-ion RT. Methods In accordance with the PRISMA guidelines and set search strategies, we searched four databases for articles from their inception to February 11, 2023. These articles were screened, and data were extracted independently by two researchers. STATA 14.0 was used for statistical analysis of survival results. Results A total of 942 related articles were retrieved, 11 of which were included. Regarding lesion location, 57% (n = 552) originated in the sacral region, 41% (n = 398) in the skull base, and 2% (n = 19) in the spine (upper cervical). The local control (LC) rates at 1, 2, 3, 5, 9, and 10 years in these studies were 96%, 93%, 83%, 76%, 71%, and 54%, respectively. The overall survival (OS) rates at 1, 2, 3, 5, 9, and 10 years in these studies were 99%, 100%, 93%, 85%, 76%, and 69%, respectively. Acute and late toxicities were acceptable, acute toxicities were mainly grade 1 to grade 2 and late toxicities were mainly grade 1 to grade 3. Conclusion C-ion RT has attractive clinical application prospects and is an important local treatment strategy for chordomas. Encouraging results were observed in terms of LC and OS. Meanwhile, the acute and late toxicities were acceptable. PROSPERO registration number: CRD42023398792.

The loss of any symmetry in a system leads to quantum problems that are typically very difficult to solve. Such a situation arises for particles with anisotropic mass, like electrons in various semiconductor host materials, where it is known that they may have an anisotropic effective mass. In this work, we consider the quantum problem of a spinless charged particle with anisotropic mass in two dimensions and study the resulting energy and eigenstate spectrum in a uniform constant perpendicular magnetic field when a Landau gauge is adopted. The exact analytic solution to the problem is obtained for arbitrary values of the anisotropic mass using a mathematical technique that relies on the scaling of the original coordinates. The characteristic features of the energy spectrum and corresponding eigenstate wave functions are analyzed. The results of this study are expected to be of interest to quantum Hall effect theory.

Objective: Carbon ion radiotherapy (C-ion RT) for chordomas has been gradually performed in several research centres. This study aimed to systematically review the results of clinical reports from these institutions and to evaluate the safety and efficacy of C-ion RT. Methods: In accordance with the PRISMA guidelines and set search strategies, we searched four databases for articles from their inception to February 11, 2023. These articles were screened, and data were extracted independently by two researchers. STATA 14.0 was used for statistical analysis of survival results. Results: A total of 942 related articles were retrieved, 11 of which were included. Regarding lesion location, 57% (n = 552) originated in the sacral region, 41% (n = 398) in the skull base, and 2% (n = 19) in the spine (upper cervical). The local control (LC) rates at 1, 2, 3, 5, 9, and 10 years in these studies were 96%, 93%, 83%, 76%, 71%, and 54%, respectively. The overall survival (OS) rates at 1, 2, 3, 5, 9, and 10 years in these studies were 99%, 100%, 93%, 85%, 76%, and 69%, respectively. Acute and late toxicities were acceptable, acute toxicities were mainly grade 1 to grade 2 and late toxicities were mainly grade 1 to grade 3. Conclusion: C-ion RT has attractive clinical application prospects and is an important local treatment strategy for chordomas. Encouraging results were observed in terms of LC and OS. Meanwhile, the acute and late toxicities were acceptable. PROSPERO registration number: CRD42023398792. [ABSTRACT FROM AUTHOR]

The technological aspects of the light inorganic crystalline compounds suitable to create scintillation materials to detect charged particles and neutrons in a wide energy range have been examined. Among them, Li2CaSiO4:Eu was found to be a prospective candidate to control the valent state of the Rare Earth (RE) and to provide a high intensity of luminescence. It was demonstrated that the material has room for future improvement; however, this requires precise engineering of its composition—an experimental search of compositions or additives that will provide the maximum Eu2+/Eu3+ ratio to achieve a high scintillation light yield. The benefits of light inorganic materials are disclosed through the modeling of the linear density of nonequilibrium carriers along secondary particle tracks created in scintillators utilized for neutron detection. It is shown that oxide matrices have a larger linear density in comparison with halide crystalline compounds under alpha-particles and tritons, whereas light oxides can provide smaller numbers under protons. [ABSTRACT FROM AUTHOR]

Purpose: The existence of cancer stem cells (CSCs) is closely related to tumor recurrence, metastasis, and resistance to chemoradiotherapy. In addition, given the unique physical and biological advantages of charged particle, we hypothesized that charged particle irradiation would produce strong killing effects on CSCs. The purpose of our systematic review is to evaluate the biological effects of CSCs irradiated by charged particle, including proliferation, invasion, migration, and changes in the molecular level. Methods: We searched PubMed, EMBASE, and Web of Science until 17 march 2022 according to the key words. Included studies have to be vitro studies of CSCs irradiated by charged particle. Outcomes included one or more of radiation sensitivity, proliferation, metastasis, invasion, and molecular level changes, like DNA damage after been irradiated. Results: Eighteen studies were included in the final analysis. The 18 articles include 12-carbon ion irradiation, 4-proton irradiation, 1 α-particle irradiation, 1-carbon ion combine proton irradiation. Conclusion: Through the extraction and analysis of data, we came to this conclusion: CSCs have obvious radio-resistance compared with non-CSCs, and charged particle irradiation or in combination with drugs could overcome this resistance, specifically manifested in inhibiting CSCs' proliferation, invasion, migration, and causing more and harder to repair DNA double-stranded breaks (DSB) of CSCs. [ABSTRACT FROM AUTHOR]

The paper presents the results of test measurements to determine the capabilities of studying the cluster structure of highly excited states of the Li nucleus using the reaction Li(n, He n) H on the RADEX neutron channel at the Institute for Nuclear Research, Russian Academy of Sciences. In the experiment, scattered neutrons were detected in coincidence with the decay products of highly excited states (helium-3). The first experimental data on the excitation energy of the Li nucleus have been obtained. [ABSTRACT FROM AUTHOR]

The article is devoted to the theoretical problems of studying cathode lenses with two planes of symmetry. It is noted that the classical methods of studying conventional electron lenses are unsuitable for a detailed study of the focusing properties of cathode lenses because these methods do not take into account the specificity of the initial conditions of cathode lenses. For a cathode lens, it is inaccurate to assume that the trajectories of charged particles throughout have a small inclination to the main optical axis. In addition, in single and immersion lenses, the condition of the smallness of the spread of charged particle energies with respect to the values of the axial potential is satisfied throughout, while in the cathode lens, this condition is not satisfied in the cathode region. The method proposed in the article is based on the study of the parameters of the trajectory of an arbitrary particle in a beam of charged particles relative to the parameters of the trajectory of an axial particle with zero initial energy, the trajectory of which is chosen as a scalar motion. The results obtained in the article will expand the scope of the application of cathode lenses with two planes of symmetry. [ABSTRACT FROM AUTHOR]

We study the motion states of charged particles in a homogeneous electromagnetic field based on the Maxwell equations. The authors propose the charged particle properties analysis based on the Maxwell equation and electromagnetic field, first explain the Maxwell equation and electromagnetic field properties analysis, and then analyze the charged particles in the composite field (electric and magnetic field coexistence). List the important knowledge points about the motion of charged particles in an electric field, and determine the center of the circle where the charged particles move in a circular motion, simulate the motion of charged particles in a uniform orthogonal electromagnetic field, if at, the trajectory of the charged particle is a short-amplitude cycloid, if, the trajectory of the charged particle is a long cycloid, if. The realization of simulation is mainly based on theory to obtain phenomena, although it has extensive practical significance for confirmatory experiments, when inspiring and guiding students to carry out inquiry learning, physics teachers should still organically combine simulation experiments with traditional experimental teaching, teacher explanations, and student experiments in teaching design and teaching implementation, in order to cultivate students' independent inquiry ability and experimental innovation ability.

The mass attenuation coefficient (MAC), effective atomic number (Zeff), equivalent atomic number (Zeq), fast neutron removal cross-section (FNRCS), energy absorption buildup factor (EABF), mass-energy absorption coefficient (MenAC), relative kerma, and computed tomography (CT) numbers were calculated for the alginates, bisphenol A-glycidyl methacrylate (Bis-GMA), chitin, hyaluronic acid, polycaprolactone (PCL), polyether ether ketone (PEEK), polyethylene glycol (PEG), polyglycolide (PGA), polylactic acid (PLA), poly lacto-co-glycolic acid (PLGA), poly methyl methacrylate (PMMA), poly vinyl alcohol (PVA), polyvinylpyrrolidone (PVP), triethylene glycol dimethacrylate (TEGDMA), and urethane dimethacrylate (UDMA) polymers using the Phy-X/PSD and Py-MLBUF software. The total stopping power (TSP) of electrons, protons, and alpha particles was calculated for the selected polymers using the ESTAR, PSTAR, and ASTAR programs. The effective atomic number for absorption and charged particle (electron, proton, alpha, and carbon ion) interactions were estimated for the selected polymers using Phy-X/ZeXTRa software. The FNRCS values of Bis-GMA, PCL, PEG, PMMA, and PVP were similar to those of the human tissues. For the selected polymers, the Zeff values for electron, proton, alpha, and carbon ion interactions of PCL, PEG, PLGA, and PVA were similar to those of human tissues, except for the cortical bone, across the entire energy range. These results are expected to assist in selecting suitable polymers as tissue-equivalent materials in the desired energy range for photon, neutron, and charged-particle interactions. This study is expected to be useful for radiation therapy and dosimetry. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Xiao and Qin (Comput Phys Commun 265:107981, 2021) recently proposed a remarkably simple modification of the Boris algorithm to compute the guiding centre of the highly oscillatory motion of a charged particle with step sizes that are much larger than the period of gyrorotations. They gave strong numerical evidence but no error analysis. This paper provides an analysis of the large-stepsize modified Boris method in a setting that has a strong non-uniform magnetic field and moderately bounded velocities, considered over a fixed finite time interval. The error analysis is based on comparing the modulated Fourier expansions of the exact and numerical solutions, for which the differential equations of the dominant terms are derived explicitly. Numerical experiments illustrate and complement the theoretical results. [ABSTRACT FROM AUTHOR]

The rapid development of electromagnetic technology has been widely used in many fields. For example, the transmission of electromagnetic waves in extreme environments (such as sandstorms and haze) and the monitoring of particle composition in the atmosphere by using electromagnetic wave technology. The properties of particles, such as particle electrification, will affect electromagnetic wave scattering and directly affect the signal transmission quality and monitoring results. Based on the scattering characteristics of electromagnetic waves of charged particles, the effects of different particle composition, different electric quantity, different humidity and different particle numbers on electromagnetic wave propagation are studied in this paper. The multiple scattering of electromagnetic waves by the random distribution of multiple particles is studied, and the Maxwell equation is converted into the Foldy–Lax multiple scattering equation, and the numerical solution is carried out. The influence of charged particle clusters on the electromagnetic scattering is analyzed. The simulation and experiment show that the charge of particles has a great influence on the electromagnetic scattering near some frequencies. [ABSTRACT FROM AUTHOR]

In order to ensure the operation of wireless communication and radar equipment during haze events, it is necessary to study the quantitative prediction of the attenuation coefficient of Electromagnetic wave (α) during haze events. The results of the dimensional analysis show that particle humidity (H p) and particle charge-to-mass ratio (Q m) are two important parameters that affect the propagation of electromagnetic waves. At the micro level, the influence of two parameters is introduced into the electromagnetic wave attenuation model through the core-shell structure. The results show that the H p and Q m will increasing α. Due to it being difficult to obtain the physical parameters in the micro-scale model by experimental methods. Therefore, this article analyzes the experimental data of Zhang et al. (2020b) and finds out that the change of α can be scaled by H p , and Q m mainly affects the slope term of the linear change of α with H p. Based on these findings, an empirical model of α considering H p and Q m was proposed. The results show that the influence of H p and Q m during haze events with high humidity cannot be ignored. And, the relative humidity has the largest contribution to α , the particle charging has the second place, and the primary release of particulate matter has the smallest contribution. The advantage of this model is that it is not only simple in form and easy to apply, but also that the input required and model parameters can be measured with experimental methods. • An empirical model of α considering H p and particle charge was proposed. • The predicted results can be in good agreement with the experimental results. • A greater attenuation by charged aerosols than uncharged aerosols under high particle humidity. [ABSTRACT FROM AUTHOR]

The technological aspects of the light inorganic crystalline compounds suitable to create scintillation materials to detect charged particles and neutrons in a wide energy range have been examined. Among them, Li2CaSiO4:Eu was found to be a prospective candidate to control the valent state of the Rare Earth (RE) and to provide a high intensity of luminescence. It was demonstrated that the material has room for future improvement; however, this requires precise engineering of its composition—an experimental search of compositions or additives that will provide the maximum Eu2+/Eu3+ ratio to achieve a high scintillation light yield. The benefits of light inorganic materials are disclosed through the modeling of the linear density of nonequilibrium carriers along secondary particle tracks created in scintillators utilized for neutron detection. It is shown that oxide matrices have a larger linear density in comparison with halide crystalline compounds under alpha-particles and tritons, whereas light oxides can provide smaller numbers under protons.

The electromagnetic interaction of a charged particle beam with multilayer vacuum chambers is of particular interest in accelerator physics. This paper presents a deep learning-based approach for calculating electromagnetic fields generated by the beam in infinitely long multilayer vacuum chambers with arbitrary cross section. The presented approach is based on physics-informed neural networks and the surface impedance boundary condition of a multilayer structure derived from the transmission line theory. Deep neural networks (DNNs) are utilized to approximate the solution of partial differential equations (PDEs) describing the physics of electromagnetic fields self-generated by a charged particle beam traveling in a particle accelerator. A residual network is constructed from the output of DNNs, the PDEs and boundary conditions are embedded into the loss function and differential operators are calculated using the automatic differentiation. As a result, the presented approach is regarded to be mesh-free. The approach is applied to circular and elliptical vacuum chambers with a three-layer structure. It is verified in comparison with the recently proposed boundary element method. The effects of chamber geometries and multilayer structure on the beam coupling impedance are demonstrated.

Neutrons constitute a significant component of the secondary cosmic rays and are one of the most important contributors to natural cosmic ray radiation background dose. The study of the cosmic ray neutrons' contribution to the dose equivalent received by humans is an interesting and challenging task for the scientific community. In addition, international regulations demand assessing the biological risk due to radiation exposure for both workers and the general population. Because the dose rate due to cosmic radiation increases significantly with altitude, the objective of this work was to characterize the thermoluminescent dosimeter (TLDs) from the perspective of exposing them at high altitudes for longtime neutron dose monitoring. The pair of TLD-700 and TLD-600 is amply used to obtain the information on gamma and neutron dose in mixed neutron-gamma fields due to the present difference in 6Li isotope concentration. A thermoluminescence dosimeter system based on pair of TLD-600/700 was characterized to enable it for neutron dosimetry in the thermal energy range. The system was calibrated in terms of neutron ambient dose equivalent in an experimental setup using a 241Am-B radionuclide neutron source coated by a moderator material, polyethylene, creating a thermalized neutron field. Afterward, the pair of TLD-600/700 was exposed at the CERN-EU High-Energy Reference Field (CERF) facility in Geneva, which delivers a neutron field with a spectrum similar to that of secondary cosmic rays. The dosimetric system provided a dose value comparable with the calculated one demonstrating a good performance for neutron dosimetry. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, 75TeO 2 –5Na 2 O–20BaO‒xTiO 2 (TNB-Tix with x = 0, 05, 10, and 15) glasses were synthesized by the conventional melt-quench technique using analytic grade tellurium oxide (TeO 2), barium carbonate (BaCO 3), sodium carbonate (Na 2 CO 3) and titanium oxide (TiO 2) as starting chemicals. The prepared glasses were studied for their physical features, Raman and UV spectra, and shielding performance against neutrons and charged particles. The optical property was investigated by UV–Vis spectrometry while the structural evolution of the glasses was studied through the Rahman spectra. Charged particles, slow and fast neutrons interaction parameters of the glasses were calculated theoretically and analyzed as well. The prepared glasses were yellowish without any flaws. The mass density of the glasses increased from 5.1 to 5.4 g/cm3 as TiO 2 content declined from 15 to 0 mol%. Also, an improvement in the optical bandgap from 2.89 to 3.2 eV was recorded as BaO content increased concerning TiO 2 while the refractive index declined from 2.43 to 2.35. Generally, the improvement in the TiO 2 content of the glasses produced a rise in the total and scattering cross section of thermal and slow neutrons respectively. In addition, the fast neutron cross section was enhanced from 0.1005 to 0.1015 cm−1 for TNB-Ti00 – TNB-Ti15 glasses. The charged particle shielding parameters showed a strong dependence on the chemical structure of the glass system. The present glass system displayed good properties that could make them useful in optical and shielding applications. [ABSTRACT FROM AUTHOR]

The Boris algorithm, a closely related variational integrator and a newly proposed filtered variational integrator are studied when they are used to numerically integrate the equations of motion of a charged particle in a mildly non-uniform strong magnetic field, taking step sizes that are much larger than the period of the Larmor rotations. For the Boris algorithm and the standard (unfiltered) variational integrator, satisfactory behaviour is only obtained when the component of the initial velocity orthogonal to the magnetic field is filtered out. The particle motion shows varying behaviour over multiple time scales: fast gyrorotation, guiding centre motion, slow perpendicular drift, near-conservation of the magnetic moment over very long times and conservation of energy for all times. Using modulated Fourier expansions of the exact and numerical solutions, it is analysed to which extent this behaviour is reproduced by the three numerical integrators used with large step sizes that do not resolve the fast gyrorotations. [ABSTRACT FROM AUTHOR]

The article is devoted to the theoretical problems of studying cathode lenses with two planes of symmetry. It is noted that the classical methods of studying conventional electron lenses are unsuitable for a detailed study of the focusing properties of cathode lenses because these methods do not take into account the specificity of the initial conditions of cathode lenses. For a cathode lens, it is inaccurate to assume that the trajectories of charged particles throughout have a small inclination to the main optical axis. In addition, in single and immersion lenses, the condition of the smallness of the spread of charged particle energies with respect to the values of the axial potential is satisfied throughout, while in the cathode lens, this condition is not satisfied in the cathode region. The method proposed in the article is based on the study of the parameters of the trajectory of an arbitrary particle in a beam of charged particles relative to the parameters of the trajectory of an axial particle with zero initial energy, the trajectory of which is chosen as a scalar motion. The results obtained in the article will expand the scope of the application of cathode lenses with two planes of symmetry.

• The flame charge is obtained by the method of charge density considering polarity. • The local area of the premixed flame exhibits either positive or negative polarity. • The polarity is regularly distributed in different zones of the premixed flame. • The regional polarity formation is related to the distribution of charged particle. The study of flame charge is helpful in analyzing the combustion regime, which is significant for optimizing energy conversion in the combustion. In this article, a method to calculate the charge density considering polarity (CDCP) for flame is presented. The charge in the flame local area is obtained by combining the effect of charged particles with positive and negative polarity. The CDCP in different zones of the premixed methane flame with three equivalence ratios of 0.9, 1.0, and 1.3 is measured in the Langmuir probe measurement experiment. The experiment result found that the regional polarity is shown in the premixed flame. Subsequently, the premixed methane flame was simulated using Fluent, and then the simulation distribution of CDCP in the premixed methane flame was obtained. The CDCP and polarity across the reactant, preheat, reaction, and product zones of the premixed flame are analyzed based on the experiment and simulation results. The CDCP of the reaction zone is greater than 0 C/m3 and reaches a peak, showing obvious positive polarity. The CDCP of the reactant zone is less than 0 C/m3, showing negative polarity. The CDCP changes rapidly from less than 0 C/m3 to greater than 0 C/m3 with the approach of the reactant zone to the preheating and reaction zones. The CDCP in the product zone gradually decreases with the increase of the distance from the reaction zone and finally less than and close to 0 C/m3, showing weak negative polarity. Finally, the cause of regional polarity formation is discussed based on the net production rate of charged particles and the velocity distribution of the flow field in the simulation results. The distribution of positive ions and electrons in the premixed flame is different due to the effect of the flow field and the different diffusion properties of charged particles. Thus, the regional polarity is exhibited in the premixed flame. [ABSTRACT FROM AUTHOR]

In this paper we investigate the motion of electrically charged test particle orbiting electrically charged higher dimensional Reissner–Nordström black holes. Specifically, we analyze the radii of the photonsphere and shadow, the innermost stable circular orbits, and the capture cross section of charged particles across various dimensions of spacetime. Our study in the capture of the charged particle encompasses both relativistic and non-relativistic regimes. Our results reveal that the electromagnetic interaction between the black hole and the charged particle significantly influences the radii of all characteristic orbits and the capture cross sections, with the electromagnetic attraction (repulsion) between them leading to an increase (decrease) in these parameters. [ABSTRACT FROM AUTHOR]

This paper presents the results of numerical studies of a three-electrode cathode lens with axial field symmetry and analyses its paraxial parameters and spatial aberrations. The resultant calculations and analysis of the focusing properties of the lens show that the values of lens aberrations become greater the greater the negative modulo value of the applied potential of the focusing electrode. The results of this work can be used in the design of electron and ion-probe technology nodes for micro- and nanoelectronics and a wide range of analytical devices. [ABSTRACT FROM AUTHOR]

Radiation of a charged particle moving in a cylindrical channel with elastic walls is studied. We assume that the particle in the channel is in free motion, periodically colliding with the channel wall. Explicit expressions for the spectrum and angular distribution of radiation are obtained. These results can be used to calculate the spectrum and radiation intensity of charged particles in carbon nanotubes of relatively great diameter. The emission spectrum is essentially a bremsstrahlung one, however, periodic collisions of the particle with the wall lead to coherent amplification of radiation at frequencies that are multiples of the collision frequency. If a beam of particles is channeled, then the multiple spectral lines merge into a continuous spectrum. [ABSTRACT FROM AUTHOR]

In high dose per pulse charged particle beams, all online detectors saturate due to ion recombination. It is therefore impossible to count detector pulses separately. Silicon carbide due to its high bandgap, high thermal conductivity, and high displacement energy, is seen as an alternative. Analyzing waveforms in real-time is challenging in terms of bandwidth, measurable energy range, sensor size, data rate. In this context, an Analog Front-End (AFE) was designed for radiation signal processing. It is based on a Transimpedance Amplifier (TIA) and Charge Sensitive Amplifier (CSA) respectively, to analyze the shape of the generated signal. The methodology used to characterize AFE for large detector capacitance is described. The results obtained from simulations, experiments, and measurements in a radiative environment are also presented. [ABSTRACT FROM AUTHOR]

This article presents the exact solution of the equation of motion for a charged particle in the electromagnetic field of circularly and linear polarized multitonal amplitude-modulated waves, as well in the presence of a constant uniform magnetic field. The motion of a charged particle in the both fields was analyzed and was expressed as dependences of its average kinetic energy on the electromagnetic waves’ intensity, on their modulation percentage, on the modulation frequency-to carrier one ratio and on the constant magnetic field strength. The solution of the equation of the charged particle’s motion in the electromagnetic field of the plane wave opens up opportunities for different applications related, in particular, to various developments of multifrequency lasers and laser modulation technology. This study was undertaken in connection with the wide practical use of high-temperature plasma.

This work investigates the effects of TeO2 and B2O3 on photon, neutron, and charged particle transmission properties of Bi2O3-BaO-LiF glass system. Photon transmission parameters were obtained via narrow beam setup simulation via FLUKA and those obtained from experimentally proved XCOM calculations. The attenuation factors of μ ρ IS and μ ρ PP control the value of μ ρ at energies greater than 1.5 MeV; however, the region of influence differs for both absorption processes. While μ ρ IS peaks occur at 3 MeV, the influence of μ ρ PP becomes appreciable at E > 5 MeV. The values of linear attenuation factor (μ) ranged from 0.2119–0.5283, 0.2085–0.5248, 0.1837–0.4676, 0.1639–0.4223, 0.1519–0.3971, 0.1370–0.3638, and 0.1222–0.3315 cm-1 as B2O3 increased from 0 to 60 mol % with step of 10, respectively. The spectra of projected range (R) of the ions and CSDA range of electrons show that the TSP of electrons in the glasses increases as B2O3 increased from 0 to 60 mol % for energy lower than 5 MeV; however, it reverses at 10 MeV. The ability of the present glass system for stopping the transmission of various radiation beams reveals its potential use for shielding applications in medical and nuclear facilities. [ABSTRACT FROM AUTHOR]

Exposure to the space radiation environment poses risks for a range of deleterious health effects due to the unique types of radiation encountered. Galactic cosmic rays are comprised of a spectrum of highly energetic nuclei that deposit densely ionizing tracks of damage along the particle trajectory. These tracks are distinct from those generated by the more sparsely ionizing terrestrial radiations, and define the geometric distribution of the complex cellular damage that results when charged particles traverse the tissues of the body. The exquisite radiosensitivity of multipotent neural stem and progenitor cells found within the neurogenic regions of the brain predispose the central nervous system to elevated risks for radiation induced sequelae. Here we show that human neural stem cells (hNSC) exposed to different charged particles at space relevant fluences exhibit significant and persistent oxidative stress. Radiation induced oxidative stress was found to be most dependent on total dose rather than on the linear energy transfer of the incident particle. The use of redox sensitive fluorogenic dyes possessing relative specificity for hydroxyl radicals, peroxynitrite, nitric oxide (NO) and mitochondrial superoxide confirmed that most irradiation paradigms elevated reactive oxygen and nitrogen species (ROS and RNS, respectively) in hNSC over a 1 week interval following exposure. Nitric oxide synthase (NOS) was not the major source of elevated nitric oxides, as the use of NOS inhibitors had little effect on NO dependent fluorescence. Our data provide extensive evidence for the capability of low doses of charged particles to elicit marked changes in the metabolic profile of irradiated hNSC. Radiation induced changes in redox state may render the brain more susceptible to the development of neurocognitive deficits that could affect an astronaut's ability to perform complex tasks during extended missions in deep space.

Neutrons constitute a significant component of the secondary cosmic rays and are one of the most important contributors to natural cosmic ray radiation background dose. The study of the cosmic ray neutrons’ contribution to the dose equivalent received by humans is an interesting and challenging task for the scientific community. In addition, international regulations demand assessing the biological risk due to radiation exposure for both workers and the general population. Because the dose rate due to cosmic radiation increases significantly with altitude, the objective of this work was to characterize the thermoluminescent dosimeter (TLDs) from the perspective of exposing them at high altitudes for longtime neutron dose monitoring. The pair of TLD-700 and TLD-600 is amply used to obtain the information on gamma and neutron dose in mixed neutron-gamma fields due to the present difference in 6Li isotope concentration. A thermoluminescence dosimeter system based on pair of TLD-600/700 was characterized to enable it for neutron dosimetry in the thermal energy range. The system was calibrated in terms of neutron ambient dose equivalent in an experimental setup using a 241Am-B radionuclide neutron source coated by a moderator material, polyethylene, creating a thermalized neutron field. Afterward, the pair of TLD-600/700 was exposed at the CERN-EU High-Energy Reference Field (CERF) facility in Geneva, which delivers a neutron field with a spectrum similar to that of secondary cosmic rays. The dosimetric system provided a dose value comparable with the calculated one demonstrating a good performance for neutron dosimetry.

A quaternary glass system described by the composition 35Pb 3 O 4 – 60SiO 2 – (5-x)ZnO – xWO 3 (0 ≤ x ≤ 5 mol%) was prepared via the ordinary method namely melt quenching. The amorphous state of this system was experimentally evaluated using X-ray diffraction. At room temperature, Fourier-transform infrared (FTIR) spectroscopy was carried out to test the structure of each specimen by using the KBr technique for wavenumber of 4000 – 400 cm−1. The FTIR test demonstrated that structural units and connectivity of the modifier oxide tetrahedral increased, whereas non-bridging oxygen decreased as ZnO was substituted by WO 3. The results of neutron transmission studies showed that 6 mm was the required thickness to reduce by half the intensity of the fast neutron beam; more specifically, the fast neutron transmission factor was 0.54, 0.53, 0.53, 0.51, and 0.49 for the prepared glass specimens G1, G2, G3, G4, and G5, respectively. For charged particles, the maximum range was observed in the high energy region (10 MeV) for all projectiles studied, with 8066.33 μm for electrons, 356.86 μm for protons, 39.30 μm for alpha particles, and 5.83 μm for carbon ions. The prepared glass system has promising features for use in various dosimetry and radiation protection applications at a neutron energy below 10 MeV. [ABSTRACT FROM AUTHOR]

The interaction of a charged particle and a rotating fullerene molecule in a fullerite crystal is investigated. The mathematical model was constructed and implemented for fullerene rotation frequencies up to 1014 Hz and velocities of an incident charged particle of the order of 103 m s−1. The study was carried out using the methods of classical molecular physics. The characteristics of the motion of the C60 fullerene molecule were determined using the laws of classical mechanics, Euler's approach, and a step-by-step numerical method of a high order of accuracy. The influence of the action of a charged particle on the nature of the motion of a rotating fullerene was analyzed according to the results of the performed numerical experiments. [ABSTRACT FROM AUTHOR]

Ion therapy has emerged as one of the preferred treatment procedures in some selective indication of cancer. The actual dose delivered to the target volume may differ from the planned dose due to wrong positioning of the patient and organ movement during beam delivery. On the other hand, some healthy tissues outside the planned volume may be exposed to radiation dose. It is necessary to determine the primary particle range and the actual exposed volume during irradiation. Many proposed techniques use secondary radiation for the purpose. The secondary radiation consists mainly of neutrons, charged fragments, annihilation photons, among others, and prompt gammas. These are produced through nuclear interaction of the primary beam with the beam line and the patient’s body tissue. Besides its usefulness in characterizing the primary beam, the secondary radiation contributes to the risk of exposure of different tissues. Secondary radiation has significant contribution in theranostics, a comparatively new branch of medicine, which combines diagnosis and therapy. Many authors have made detailed study of the dose delivered to the patient by the secondary radiation and its effects. They have also studied the correlation of secondary charged particles with the beam range and the delivered dose. While these studies have been carried out in great detail in the case of proton and carbon therapy, there are fewer analyses for theranostics. In the present review, a brief account of the studies carried out so far on secondary radiation in ion therapy, its effect, and the role of nuclear reactions is given.

This study aimed to examine nuclear radiation shielding properties of a novel glass system, which has nominal compositions (40-x) B 2 O 3 +40Pb 3 O 4 +20ZnO + xEr 2 O 3 with several substitution proportions of Er 2 O 3 (x = 0, 1, 2, 3, 4 and 5). The conventional solid-state method was utilized to fabricate the Er 2 O 3 doped glasses. To obtain the amorphous nature of manufactured glass samples, X-ray diffraction (XRD) patterns were investigated. Moreover, mass attenuation coefficients (μ/ρ) of the prepared glasses were adjusted by employing MCNPX simulation code. Other important gamma-ray attenuation parameters namely Half Value Layer (HVL), Mean Free Path (MFP), Effective and Equivalent Atomic Numbers (Z eff and Z eq) and Exposure Buildup Factor (EBF) of the glasses were also extensively addressed by obtaining mass attenuation coefficients (μ/ρ). The outcomes indicated that the Er 2 O 3 additive enhances the photon attenuation qualification of the glasses. Moreover, the success of glasses in reducing fast neutrons was judged by calculating effective removal cross sections (Σ R). The results showed that increasing Er 2 O 3 additive upgraded the prepared glasses in the attenuation of neutrons as in gamma rays. In addition, the protection ability of the fabricated glasses against alpha and proton charged particles was also evaluated. Charged alpha and proton particles in BPZE5 glass have the shortest projected ranges which are 50.38 μm and 436.36 μm respectively. It was seen that the increase of Er 2 O 3 additive upgraded the prepared glasses in terms of attenuation of all of the selected radiation types. It can be deduced that these results might help for estimating the effect of Er 2 O 3 on different glass systems in the future. [ABSTRACT FROM AUTHOR]

In this challenging analytic survey, we present a new approach for solving equations of the dynamics of a charged particle (describing its motion in variable, time-dependent electromagnetic field) which has been applied earlier in various fields of mechanics for solving equations of hydrodynamics, Euler–Poisson equations of rigid body rotation and even in celestial mechanics (solution of equations of small body's motion in the CR3BP problem near librations points): a new type of the solving procedure is implemented in all of these equations as well as in case of solving momentum equation for the aforementioned dynamics of a charged particle, determined by Lorentz force in non-relativistic case. Meanwhile, in each case the system of momentum equations has been successfully solved analytically. The main result of the current research should be formulated as follows: the analytic algorithm is pointed out for solving momentum equation, which has been reduced to the analytical solution of three nonlinear ODEs with respect to the components of velocity of the particle. Moreover, absolutely new partial analytical solutions have been obtained for the special cases of magnetic field (with zero electric field's components). In addition to this, we conclude that system of Lorentz momentum equations for dynamics of a charged particle has not the analytical presentation of solution in case of nonzero, time-dependent electric field. [ABSTRACT FROM AUTHOR]