Energy Charged Particles Research Articles

Observations of GRB 221009A by the MAVEN-SEP Instrument at Mars

We report on the detection of the Brightest Of All Time (the BOAT) gamma-ray burst (GRB) 221009A by the MAVEN Solar Energetic Particle (SEP) silicon (Si) detectors. The SEP instrument on board the MAVEN spacecraft at Mars is designed to measure charged particle fluxes and energies. In this work, we show that the SEP Si detectors have detected populations of secondary charged particles and low-energy primary photons from the GRB. Our analysis relies on a series of simplified Geant4 Monte Carlo simulations. We show that electromagnetic and hadronic interactions between the GRB photons and the spacecraft’s passive material and Si detectors produced the detected secondary particles.

Research on a Neutron Detector with a Boron-Lined Multilayer Converter

3He is a splendid neutron detection material due to its high neutron reaction cross section, gaseous state, and nonelectronegative and nonpoisonous nature. With the worldwide problem of the “3He supply crisis” arising, boron-lined gaseous neutron detectors are being widely used in neutron detection to replace 3He neutron detectors. In this work, to reduce the scattering neutron background coming from the substrate of a boron-lined neutron detector in the application of neutron scattering, a new design of the boron-lined gaseous neutron detector composed of a boron-lined multichip converter and a multiwire proportional chamber was proposed. The electron drift efficiency matrix simulated by Garfield++ (Version 2023.4) and the values and positions of electron energy deposition simulated by Geant4 were obtained. The α, 7Li, and total charged particle energy deposition spectra were acquired via coupling calculations of the electron drift efficiency matrix and the values and positions of electron energy deposition, and the width of the slit was selected as 3 mm. The boron-lined multilayer converter neutron detector (BMCND) was tested using a 241Am–239Pu mixture α source, and the total count rate of α charged particles was measured as 599.5 s−1, which is 89% of the theoretical α particle emission rate of 672.9 s−1. The drift voltage experiments showed that 1200 V is enough to acquire a relatively ideal count, and a 2500 V drift voltage was confirmed, considering the higher count and instrument safety. We also performed the neutron detection experiments using a photo-neutron source, and a characteristic spectrum shape of “two stairs” was measured. When borated polyethylene was used to shield the BMCND, the detected total count decreased while keeping the characteristic spectrum shape, demonstrating that the BMCND was equipped with the ability to detect neurons, indicating that BMCNDs have the potential to be an outstanding 3He alternative neutron detector.

Real-time signal detection for Cyclotron Radiation Emission Spectroscopy measurements using antenna arrays

Cyclotron Radiation Emission Spectroscopy (CRES) is a technique for precision measurement of the energies of charged particles, which is being developed by the Project 8 Collaboration to measure the neutrino mass using tritium beta-decay spectroscopy. Project 8 seeks to use the CRES technique to measure the neutrino mass with a sensitivity of 40 meV, requiring a large supply of tritium atoms stored in a multi-cubic meter detector volume. Antenna arrays are one potential technology compatible with an experiment of this scale, but the capability of an antenna-based CRES experiment to measure the neutrino mass depends on the efficiency of the signal detection algorithms. In this paper, we develop efficiency models for three signal detection algorithms and compare them using simulations from a prototype antenna-based CRES experiment as a case-study. The algorithms include a power threshold, a matched filter template bank, and a neural network based machine learning approach, which are analyzed in terms of their average detection efficiency and relative computational cost. It is found that significant improvements in detection efficiency and, therefore, neutrino mass sensitivity are achievable, with only a moderate increase in computation cost, by utilizing either the matched filter or machine learning approach in place of a power threshold, which is the baseline signal detection algorithm used in previous CRES experiments by Project 8.

Energy mapping of Jupiter's auroral electrons from Juno/UVS data using a new H2 UV emission model

Juno, which studies the Jovian system, continues to expand our knowledge of Jupiter's magnetosphere and its environment. Thanks to onboard instruments such as Jupiter Energetic Particle Detector Instrument (JEDI) and Jovian Auroral Distributions Experiment (JADE), in situ measurements have allowed us to derive a realistic representation of charged particle energy distributions precipitating in the auroral regions. Because of the distance between Juno's measurement location and the position of impact of the charged particles, where auroral emissions are produced, these energetic distributions of magnetospheric particles are likely to be affected by various phenomena such as wave-particle interactions on their way from Juno to the atmosphere. These processes can accelerate or decelerate the particles, changing their average energies. Hence, the energy distributions of particles measured at Juno's altitude are likely different from those at auroral altitudes. In this study we develop a UV emission model, combined with an electron transport model, that allows us to relate the auroral emission spectra of H$_ $ molecules with the energy distribution of impinging electrons. Thanks to observations of the Jovian aurora by the Ultraviolet Spectrograph (UVS) on board Juno, we determined the characteristic energies of electrons precipitating in auroral regions during perijove 32. We modeled the relationship between color ratio (CR) and the characteristic energy of precipitating electrons. Initially, we considered mono-energetic electron fluxes. In a second step, we considered fluxes governed by a kappa distribution. We derived characteristic energy maps for electrons precipitating in Jupiter's auroral regions. In comparison with similar previous studies based on Space Telescope Imaging Spectrograph on board Hubble Space Telescope (HST/STIS) observations, we find that modeling the CR with a mono-energetic distribution leads to a systematic underestimation of the average energy of electrons precipitating in the auroral regions by a factor of 3-5. In this study we show that it is possible to derive a more realistic estimate of electron energy flux distributions at auroral altitudes.

Influence of bremsstrahlung on the heat balance of high-temperature plasma

The bremsstrahlung in the heat balance of a high-temperature plasma is soft X-ray, which cannot be directly converted into electricity, as is possible in the case of charged particle energy or cyclotron radiation. Bremsstrahlung is the main radiation mechanism at temperatures of several keV. For the operating temperatures of alternative fuel reactors, calculations of relativistic electron bremsstrahlung have been performed and approximating formulas have been obtained. The radiation losses are given depending on the plasma radius and the temperature.

Charged spinning and magnetized test particles orbiting quantum improved charged black holes

In the present work, we aimed to investigate the dynamics of spinning charged and magnetized test particles around both electrically and magnetically charged quantum-improved black holes. We derive the equations of motion for charged spinning test particles using the Mathisson-Papapetrou-Dixon ***equations with the Lorentz coupling term. The radius of innermost stable circular orbits (ISCOs), specific angular momentum, and energy for charged spinless, uncharged spinning, and charged spinning test particles around the charged and non-charged quantum-improved black holes are analyzed separately. We found that the quantum parameter increases the maximum spin value, smax\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$s_\ extrm{max}$$\\end{document}, which leads to the nonphysical motion (superluminal motion) of the charged spinning test particle. In contrast, the black hole charge decreases its value. We also found that, in contrast to the Reissner Nordström black hole, spinning charged test particles in the quantum-improved charged black hole have higher smax\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$s_\ extrm{max}$$\\end{document}; moreover, positively charged spinning particles can have higher values of smax\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$s_\ extrm{max}$$\\end{document} near the extreme black hole cases when compared with uncharged spinning particles. Finally, we investigate the magnetized test particle’s dynamics in the spacetime of a quantum-improved magnetically charged black hole in Quantum Einstein Gravity using the Hamilton–Jacobi equation. We show that the presence of ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega $$\\end{document} increases the maximum value of the effective potential and decreases the minimum energy and angular momentum of magnetized particles at their circular orbits. We found an upper constraint in the black hole charge at the ISCO.

Influence of pulse width on the breakdown process of nanosecond pulse discharge at low pressure

Pulsed plasma discharge breakdown has long been a subject of research in the field of plasma physics. However, the spatial distribution and temporal evolution of parameters such as the density, energy, and electric field of charged particles during the breakdown process have not been thoroughly investigated. In this study, we investigate the breakdown process under nanosecond pulses with different pulse widths (1 ns, 10 ns, and 100 ns), utilizing the 1D implicit particle-in-cell/Monte Carlo collision method. Our simulation results indicate that pulse width plays a crucial role in the evolution of plasma breakdown. Specifically, under ultra-short pulses, the breakdown occurs after the pulse voltage ceases, demonstrating that increasing pulse width accelerates the changes in plasma parameters but does not affect the breakdown time. Under longer pulses, the removal of voltage leads to a significant increase in the thickness of the anode sheath. As the pulse width continues to increase, the ions collide in the cathode sheath after the pulse ends, resulting in ion energy loss. Finally, by scanning the parameter space, we give the Paschen curve and observe a higher breakdown voltage in the pulse case and the impact of ion secondary electrons.

Characterizing Low-Energy Charged Particles in the Magnetosphere with the LEM CubeSat Spectrometer Project: Detector Concept and Hardware Characterisation

An accurate flux measurement of low-energy charged particles trapped in the magnetosphere is necessary for space weather characterization and to study the coupling between the lithosphere and magnetosphere, which allows for the investigation of the correlations between seismic events and particle precipitation from Van Allen belts. In this work, the project of a CubeSat space spectrometer, the low-energy module (LEM), is shown. The detector will be able to perform an event-based measurement of the energy, arrival direction, and composition of low-energy charged particles down to 0.1 MeV. Moreover, thanks to a CdZnTe mini-calorimeter, the LEM spectrometer also allows for photon detection in the sub-MeV range, joining the quest for the investigation of the nature of gamma-ray bursts (GRBs) and terrestrial gamma-ray flashes (TGFs). The particle identification of the LEM relies on the ΔE−E technique performed by thin silicon detectors. This multipurpose spectrometer will fit within a 10 × 10 × 10 cm3 CubeSat frame, and it will be constructed as a joint project between the University of Trento, FBK, and INFN-TIFPA. To fulfil the size and mass requirements, an innovative approach, based on active particle collimation, was designed for the LEM; this avoids the heavy/bulky passive collimators of previous space detectors. In this paper, we will present the LEM geometry, its detection concept, the results from the developed GEANT4 simulation, and some characterisations of a candidate silicon detector for the instrument payload.

Correction of the Mathematical Method for Studying a Cathode Lens with Two Planes of Symmetry

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.

Segmented silicon-based solid-state detector with thin dead layer for superheavy element research

Silicon-based solid-state detectors (SSDs) are crucial for investigating the properties of superheavy elements (SHEs), since they measure the energy of SHEs and charged particles that are emitted as successive decay events of the SHEs. We have developed a segmented SSD for SHE studies using the new gas-filled recoil ion separators (GARIS-II and GARIS-III) at RIKEN. It is based on a back-illuminated Si PIN photodiode in which the irradiation is through the N+ layer. The detector is introduced as a side one for the GARIS focal plane detection system. To investigate the characteristics of the SSD, 241Am α particles were irradiated by automatically moving and rotating the α source for each segmented portion of the SSD. A Monte Carlo simulation was also performed to estimate the dead layer thickness of the segmented SSD.

Adiabatic Amplification of Energy and Magnetic Moment of a Charged Particle after the Magnetic Field Inversion.

We study the evolution of the energy and magnetic moment of a quantum charged particle placed in a homogeneous magnetic field, when this field changes its sign adiabatically. We show that after a single magnetic field passage through zero value, the famous adiabatic invariant ratio of energy to frequency is reestablished again, but with a proportionality coefficient higher than in the initial state. The concrete value of this proportionality coefficient depends on the power index of the frequency dependence on time near zero point. In particular, the adiabatic ratio of the initial ground state (with zero radial and angular quantum numbers) triplicates if the frequency tends to zero linearly as a function of time. If the Larmor frequency attains zero more than once, the adiabatic proportionality coefficient strongly depends on the lengths of the time intervals between zero points, so that the mean energy behavior can be quasi-stochastic after many passages through zero value. The original Born-Fock adiabatic theorem does not work after the frequency passes through zero. However, its generalization is found: the initial Fock state becomes a wide superposition of many instantaneous Fock states, whose weights do not depend on time in the new adiabatic regime.

Harmless process of organic matter in organosilicon waste residue by fluidization-like DDBD reactor: Temperature action and mechanism

Herein, the non-hazardous application of low-temperature plasma technology in solid waste from the silicone industry was investigated by using a fluidization-like double dielectric barrier discharge plasma (DDBD) reactor. The results show ∼92.9% TOC in the organosilicon waste residue could be removed at the conditions (Discharge power: 7.0 W, S/G: 12.5 gminL−1, SIE: 158.0 JL-1), i.e. TOC content decreases from 166.0 g/kg to 11.8 g/kg. At the same time, the energy efficiency of the TOC removal rate reach ∼732.1 gkWh−1, and the temperature of the discharge zone is below 280 °C. According to the TG-MS analysis and infrared thermal imager, it is considered that the heat energy generated in the plasma treatment process can affect the decomposition of organic matter. On the other hand, the samples were characterized before and after treatment by BET, SEM, XRD, FTIR, and GC-MS. It was proposed the organic matter was firstly gasified under the action of plasma and thermal. Then, the active group will generate and react with the C–H, C–C, or C–Si by the bombardment of sufficient energy of charged particles, leading the organic matter further to decompose into small molecules, such as CH4, H2, CO, and CO2.

Light energy distribution of submicron charged particles based on the scattering-enhancing effect

Magnetic microspheres, charged soot and other charged sub-micron particles are widely used, and the accurate measurement of their particle size is crucial to biomedical, environmental monitoring and other fields. During light scattering measurements, the light energy distribution projected onto each ring surface of the photodetector is the core data for particle size inversion calculations. When the measured particle is charged, the light energy distribution will be different from its neutral state due to the scattering-enhancing effect of surface charges. Therefore, it is necessary to confirm the extent of the scattering-enhancing effect on the light energy distribution by numerical simulation, before actual measurement. In this paper, calculation models of scattered light energy distribution are established for charged single particle, monodisperse particle system and polydisperse particle system respectively. Considering the difference between the complex refractive indices of charged particles, the forward scattering of silica and polystyrene with different monodisperse degrees are taken as an example to analyze the light energy distribution. The results show that the scattering-enhancing effect of surface charges can affect the light energy distribution of submicron particles, and the smaller the median diameter of the particle system and the lower the monodisperse degree, the more significant the effect is. At a median diameter of 0.1 μm, the light energy of charged particles with different monodisperse degrees increased by an average of about 3.5 times, near the scattering angle of 45° This research realizes the forward deduction of the light energy distribution for charged particles, and provides the necessary theoretical support for the visible light measurement of charged submicron and nanoparticles.

Reconstruction algorithm for a novel Cherenkov scintillation detector

For future MeV-scale neutrino experiments, a Cherenkov scintillation detector, CSD, is of particular interest for its capability to reconstruct both energy and direction for charged particles. A type of new target material, slow liquid scintillator, SlowLS, which can be used to separate Cherenkov and scintillation lights, is one of the options for the neutrino detectors. A multi-hundred ton spherical CSD is simulated using a Geant4-based Monte Carlo software, which handles the detailed the micro processes of MeV particles and optical photons and the functions for photomultiplier, PMT, and readout electronics. Twelve SlowLS samples are simulated and studied to cover a wide range of scintillation light yields and scintillation emission time constants. Based on the detailed knowledge of the signal processes, simplified functions are constructed to predict the charge and time signals on the PMTs to fulfill an efficient reconstruction for the energy, direction, and position of charged particles. The performance of the SlowLS reconstruction, including the resulting energy, angular, and position resolution, and particle identification capability, is presented for these samples. The dependence of the performance on the scintillation light yield and emission time constants is understood. This study will be a guideline for future MeV-scale neutrino CSD design and SlowLS development for the interested physics goals.

SYNCA: A Synthetic Cyclotron Antenna for the Project 8 Collaboration

Cyclotron Radiation Emission Spectroscopy (CRES) is a technique for measuring the kinetic energy of charged particles through a precision measurement of the frequency of the cyclotron radiation generated by the particle's motion in a magnetic field. The Project 8 collaboration is developing a next-generation neutrino mass measurement experiment based on CRES. One approach is to use a phased antenna array, which surrounds a volume of tritium gas, to detect and measure the cyclotron radiation of the resulting β-decay electrons. To validate the feasibility of this method, Project 8 has designed a test stand to benchmark the performance of an antenna array at reconstructing signals that mimic those of genuine CRES events. To generate synthetic CRES events, a novel probe antenna has been developed, which emits radiation with characteristics similar to the cyclotron radiation produced by charged particles in magnetic fields. This paper outlines the design, construction, and characterization of this Synthetic Cyclotron Antenna (SYNCA). Furthermore, we perform a series of measurements that use the SYNCA to test the position reconstruction capabilities of the digital beamforming reconstruction technique. We find that the SYNCA produces radiation with characteristics closely matching those expected for cyclotron radiation and reproduces experimentally the phenomenology of digital beamforming simulations of true CRES signals.

INFLUENCE OF MAGNETIC FIELD CONFIGURATION AND STRENGTH ON PLASMA PARAMETERS AND EFFICIENCY OF COATINGS DEPOSITION IN MAGNETRON SPUTTERING SYSTEM

Paper presents results of evaluation of the influence of the parameters of the additional anode electromagnetic trap for discharge electrons in a magnetron sputtering system. The efficiency of ionization processes is also investigated. It has been shown experimentally that a slight increase of the additional anode magnetic field leads to an increase of plasma density in the discharge on several times. The presence of an anode electromagnetic trap causes additional ionization zones. An increase of anode magnetic field leads to an increase of the average energy of charged discharge plasma particles. As the result, it was observed an intensification of the target material sputtering process as well as an increase of coatings deposition rate. In addition, a slight increase in the magnitude of the anode magnetic field has a positive effect on the quality and purity of the deposited coatings.

Effect of the electronic pressure on the energy and magnetic moment of charged test particles in turbulent electromagnetic fields

In this work, we perform direct numerical simulations of three-dimensional magnetohydrodynamics with a background magnetic field, representing solar wind plasma, and introduce test particles to explore how a turbulent electromagnetic environment affects them. Our focus is on the terms of the electric field present in the generalized Ohm's law that is usually dismissed as unimportant. These are the Hall and the electronic pressure (EP) terms, but we concentrate primarily on the latter. We discover that the EP term generates an acceleration of the particles, which represent protons, in the direction parallel to the background magnetic field, in contrast to the known preferential perpendicular energization. By studying the electric field itself, we are able to detect the type of structures of the EP field that produce such parallel acceleration. These are thin and elongated structures placed on top of a monotonic and near-zero background. A statistical study to understand the real significance of the electronic pressure term is also performed.

Recoil and charged particle energy spectra from the natSi(n,x) reaction and the Si semiconductor detector response to the 14 MeV neutrons

The energy spectra of light and heavy charged particles generated by the 14 MeV neutrons in silicon nuclei and in the Si semiconductor detector (SSD) were analysed. The existing measurements were used to validate the corresponding energy differential cross sections from major evaluations ENDF/B-VIII.0 and JEFF-3.3. The required data were extracted by the various codes: NJOY21, SPKA and MCNP6. It was shown that both evaluations underestimate the high energy part of the 28Si(n,x)p- and α-particle spectra by ≤50%, whereas at smaller emission energies no experimental data even exist. The calculation of the atom displacement damage in SSD reveals that the secondary protons produce additionally ≈15% of damage, whereas the contribution from secondary alphas is impossible to estimate since the Si(α,x) recoil data are not available.The single experiment, carried out by K. Yageta and co-workers in 1988, reported the energy spectra in the Si semiconductor down to the rather low energy of ≈0.3 MeV, at which the production of reaction recoils dominates over the light ions. The Monte Carlo simulation of this experiment was performed by MCNP6. The generation and transport of all relevant ions were taken in account. The energy depositions from protons or alphas were summed with their associated recoils after correction for non-ionization losses. The neutron reactions in the dead layer of the SSD were shown to increase the counts in active layer by (1–20)% depending on sort of ions. The impact of the field funneling effect was studied. Consideration of all these underlying processes has eventually allowed a reasonable reproduction of this experiment.

Effect of diffusion on the peak value of energy loss observed in a LArTPC

Liquid Argon Time Projection Chamber (LArTPC) detectors observe ionization electrons to measure charged particle trajectories and energy. In a LArTPC, the long time (∼ms) between when the ionization is produced and when it is collected means that diffusion can smear the charge by an amount comparable to the spatial resolution of the detector, given by the spacing between charge sensing channels (∼mm). This smearing has an impact on the distribution of energy losses measured by each channel. In particular, the smearing increases the length of the charged particle trajectory observed by each channel, and therefore the most-probable-value (MPV) of particle energy loss recorded by that channel. We find, for example, that this effect shifts the MPV dE/dx of a muon with an energy of 1 GeV by ∼4% for a 2 ms drift time and 4.7 mm wire spacing, as in the DUNE-FD LArTPC. This has implications for the energy-scale calibration and electron lifetime measurements in a LArTPC, which both use the MPV of the muon energy loss distribution as a “standard candle”. The impact of diffusion on these calibrations is assessed.

Investigation of Monte Carlo simulations of the electron transport in external magnetic fields using Fano cavity test

PurposeMonte Carlo simulations are crucial for calculating magnetic field correction factors kB for the dosimetry in external magnetic fields. As in Monte Carlo codes the charged particle transport is performed in straight condensed history (CH) steps, the curved trajectories of these particles in the presence of external magnetic fields can only be approximated. In this study, the charged particle transport in presence of a strong magnetic field B→ was investigated using the Fano cavity test. The test was performed in an ionization chamber and a diode detector, showing how the step size restrictions must be adjusted to perform a consistent charged particle transport within all geometrical regions. MethodsMonte Carlo simulations of the charged particle transport in a magnetic field of 1.5 T were performed using the EGSnrc code system including an additional EMF-macro for the transport of charged particle in electro-magnetic fields. Detailed models of an ionization chamber and a diode detector were placed in a water phantom and irradiated with a so called Fano source, which is a monoenergetic, isotropic electron source, where the number of emitted particles is proportional to the local density. ResultsThe results of the Fano cavity test strongly depend on the energy of charged particles and the density within the given geometry. By adjusting the maximal length of the charged particle steps, it was possible to calculate the deposited dose in the investigated regions with high accuracy (<0.1%). The Fano cavity test was performed in all regions of the detailed detector models. Using the default value for the step size in the external magnetic field, the maximal deviation between Monte Carlo based and analytical dose value in the sensitive volume of the ion chamber and diode detector was 8% and 0.1%, respectively. ConclusionsThe Fano cavity test is a crucial validation method for the modeled detectors and the transport algorithms when performing Monte Carlo simulations in a strong external magnetic field. Special care should be given, when calculating dose in volumes of low density. This study has shown that the Fano cavity test is a useful method to adapt particle transport parameters for a given simulation geometry.