High-energy Charged Particles Research Articles

Past activity of Sgr A⋆ is unlikely to affect the local cosmic-ray spectrum up to the TeV regime

Context The presence of kiloparsec-sized bubble structures on both sides of the Galactic plane suggests active phases of Sgr A⋆, the central supermassive black hole of the Milky Way in the last 1–6 Myr. We investigated the contribution of such events to the cosmic-ray (CR) flux measured in the solar neighborhood with numerical simulations. Aims. We evaluate whether the population of high-energy charged particles emitted by the Galactic center could be sufficient to significantly impact the CR flux measured in the solar neighborhood. Methods. We present a set of 3D magnetohydrodynamical simulations following the anisotropic propagation of CRs in a Milky Way-like Galaxy. We followed independent populations of CRs through time. We followed CRs originating from two different source types, namely supernovae and the Galactic center. To assess the evolution of the CR flux spectrum properties, we split these populations into two independent energy groups of 100 GeV and 10 TeV. Results. We find that the anisotropic nature of CR diffusion dramatically affects the amount of CR energy received in the solar neighborhood. The typical timescale required to observe measurable changes in the CR spectrum slope is of the order 10 Myr, largely surpassing estimated ages of the Fermi bubbles in the active galactic nuclei (AGN) jet-driven scenario. Conclusions. We conclude that a CR outburst from the Galactic center in the last few million years is unlikely have produced any observable feature in the local CR spectrum in the TeV regime within times consistent with current estimates of the age of the Fermi bubbles.

Remote sensing of high energy charged particle current (HEC) for megavoltage therapeutic electron beams

Objective. We demonstrate detection of high energy particle current (HEC) for MeV therapeutic electron beams. Detection of HEC comprises of remote sensing or acquiring information about HEC inside radiation transport medium from a distance outside of the medium. Approach. HEC is self-propelled motion of charged particles through a radiation transport medium. Remote sensing of HEC is embodied in an experimental setup, which includes homogeneous and heterogeneous phantoms irradiated with 4–15 MeV electron beams and two large area parallel-plane electrodes extraneous to the phantoms providing two-parameter detection. We also introduce a new type of scanning method (depth-scan) for probing object properties along the beamline axis. Main Results. Deterministic radiation transport simulations and measurements agree, considering differences in simulation vs experimental geometry and experimental uncertainties. Significance. This method may be suitable for range detection of charged particle beams, or for probing of radiation opaque objects in non-destructive testing.

STRUCTURAL CHANGES IN CORTICAL BONE AFTER BOMBARDMENT WITH LOW-ENERGY HYDROGEN IONS

Radiobiological studies focused mainly on tracking the effects of photons (X and gamma rays) and high-energy charged particles over low energy ions, which raises interest in studying their biological effects. Therefore, the aim of this study is to investigate the interaction of low-energy hydrogen ions beam with xcortical bovine bone as a biological model. A hydrogen ions beam was used to bombard cortical bone with different fluences; 45, 70 and [Formula: see text][Formula: see text]ions/cm2 at low energy of 5[Formula: see text]keV. The interaction of hydrogen ions with cortical bone was estimated theoretically by the SRIM/TRIM code. The obtained results showed that the average distribution range and the maximum depth for 5[Formula: see text]keV hydrogen ions are 91 and 150[Formula: see text]nm respectively. The energy losses from incident ions are 4.45[Formula: see text]keV for ionization, 170[Formula: see text]eV for phonons and 18[Formula: see text]eV for vacancies. Also, the energy losses from the recoil atoms are 119[Formula: see text]eV for ionization, 234[Formula: see text]eV for phonons and 8[Formula: see text]eV for vacancies. At the same time, the effect of low-energy hydrogen ions bombardment on the structure of bone was studied by X-ray diffraction (XRD) and FTIR.

Synergistic Effects of Total Ionizing Dose and Single-Event Upset in 130 nm 7T Silicon-on-Insulator Static Random Access Memory

The exposure of spaceborne devices to high-energy charged particles in space results in the occurrence of both a total ionizing dose (TID) and the single-event effect (SEE). These phenomena present significant challenges for the reliable operation of spacecraft and satellites. The rapid advancement of semiconductor fabrication processes and the continuous reduction in device feature size have led to an increase in the significance of the synergistic effects of TID and SEE in static random access memory (SRAM). In order to elucidate the involved physical mechanisms, the synergistic effects of TID and single-event upset (SEU) in a new kind of 130 nm 7T silicon-on-insulator (SOI) SRAM were investigated by means of cobalt-60 gamma-ray and heavy ion irradiation experiments. The findings demonstrate that 7T SOI SRAM is capable of maintaining normal reading and writing functionality when subjected to TID irradiation at a total dose of up to 750 krad(Si). In general, the TID was observed to reduce the SEU cross-section of the 7T SOI SRAM. However, the extent of this reduction was influenced by the heavy ion LET value and the specific writing data pattern employed. Based on the available evidence, it can be proposed that TID preirradiation represents a promising avenue for enhancing the resilience of 7T SOI SRAMs to SEU.

Electron-Induced Single-Event Effect in 28 nm SRAM-Based FPGA

As the feature size of integrated circuit decreases, the critical charge of single-event effect decreases as well, making nano-scale devices more susceptible to the high-energy charged particles during their application in space. Here, we study the electron-induced single-event effect in 28 nm static random-access memory (SRAM)-based field programmable gate array (FPGA) utilizing high-energy electrons with energy of 1 MeV~5 MeV. The experimental results demonstrate that the 3 MeV electrons can cause single-event functional interrupts (SEFIs) in FPGA, while the electrons with other energies cannot. To further explore the mechanism of electron-induced SEFIs in this nanoscale FPGA, we combined Monte Carlo, Technology Computer-Aided Design (TCAD), and Simulation Program with Integrated Circuit Emphasis (SPICE) simulations. It is revealed that the SEFI was mainly caused by the direct ionization effect of high-energy electrons, and the SEFI was related to the interactions between multiple sensitive nodes.

Ionic liquid coating for charge mitigation of solar modules in space: Electron microscopy on insulating nanosphere lithography patterned surfaces

Surfaces of satellites and spacecrafts are exposed to high energy charged particles from the solar wind, especially during space weather events. This can lead to differential charging, which is a common reason for hardware degradation and sensor errors. Solutions like coatings are required to avoid excessive cost and weight. Mimicking the electron part of space-like environments in ultra-high vacuum (UHV) chambers can be achieved by using electrons emitted by a scanning electron microscope (SEM). As a performance test for the discharge capabilities we use the quality of electron microscopy images on otherwise insulating substrates such as glass, structured by nanosphere lithography and coated with an ionic liquid (IL). Additionally, the surface potential was measured by Kelvin Probe Force Spectroscopy. The IL film (BMP DCA) was applied ex situ and a thickness of 12.8 ($\pm$0.8)\,nm was determined by reflectometry and confirmed by dynamic atomic force microscopy. Such a film of ionic liquid would lead to additional mass of below 20\,mg and negligible additional material costs. The light absorption and influence of ionic liquid coatings on the current output of an actual solar cell were investigated. The results indicate, that these coatings are promising candidates for surface charge mitigation with a high potential for application

Chorus wave power at the strong diffusion limit overcomes electron losses due to strong diffusion

Earth’s radiation belts consist of high-energy charged particles trapped by Earth’s magnetic field. Strong pitch angle diffusion of electrons caused by wave-particle interaction in Earth’s radiation belts has primarily been considered as a loss process, as trapped electrons are rapidly diffused into the loss cone and lost to the atmosphere. However, the wave power necessary to produce strong diffusion should also produce rapid energy diffusion, and has not been considered in this context. Here we provide evidence of strong diffusion using satellite data. We use two-dimensional Fokker-Planck simulations of electron diffusion in pitch angle and energy to show that scaling up chorus wave power to the strong diffusion limit produces rapid acceleration of electrons, sufficient to outweigh the losses due to strong diffusion. The rate of losses saturates at the strong diffusion limit, whilst the rate of acceleration does not. This leads to the surprising result of an increase, not a decrease in the trapped electron population during strong diffusion due to chorus waves as expected when treating strong diffusion as a loss process. Our results suggest there is a tipping point in chorus wave power between net loss and net acceleration that global radiation belt models need to capture to better forecast hazardous radiation levels that damage satellites.

Remarkable reduction in thermal contact resistance between target and heat exchanger using TIMs in isotope neutron source accelerator

The high thermal contact resistance (TCR) between the target and the heat exchanger in the Isotope Neutron Source Accelerator will cause the high-energy charged particle beam to stay in the target, resulting in a remarkable increase of temperature which affects the production of stable isotopes. At present, the usage of thermal interface materials (TIMs) can fill the gap at the contact surface and thus reduces the TCR. In this paper, aiming at the actual working condition of neutron source, the steady-state TCR measurement experiment is designed under vacuum and high temperature environment. The TCR at the contact surface was reduced after adding graphite films, thermal greases, liquid metals and preloads. The improvement of TCR of the contact surface between palladium (Pd), copper (Cu) and graphite (Gr) were measured respectively. The results show that the TCR between palladium and graphite is reduced by 95 % by adding liquid metal (Gallium alloy). The TCR between copper and graphite was reduced by 91 % by brazing method. Compared with other TIMs, graphite film has the advantages of high thermal conductivity, high temperature resistance and no fluidity. Adding 0.08 mm thick graphite film between Pd/Gr and Cu/Gr contact surface can reduce the TCR by 50 % and 70 %, respectively. The improvement effect between the two contact surfaces was not obvious when 15.9–318.3 kPa preload was applied.

A combined AIMD and DFT study of the low-energy radiation responses of GaN.

Although GaN is a promising candidate for semiconductor devices, degradation of GaN-based device performance may occur when the device is bombarded by high-energy charged particles during its application in aerospace, astronomy, and nuclear-related areas. It is thus of great significance to explore the influence of irradiation on the microstructure and electronic properties of GaN and to reveal the internal relationship between the damage mechanisms and physical characteristics. Using a combined density functional theory (DFT) and ab initio molecular dynamics (AIMD) study, we explored the low-energy recoil events in GaN and the effects of point defects on GaN. The threshold displacement energies (Eds) significantly depend on the recoil directions and the primary knock-on atoms. Moreover, the Ed values for nitrogen atoms are smaller than those for gallium atoms, indicating that the displacement of nitrogen dominates under electron irradiation and the created defects are mainly nitrogen vacancies and interstitials. The formation energy of nitrogen vacancies and interstitials is smaller than that for gallium vacancies and interstitials, which is consistent with the AIMD results. Although the created defects improve the elastic compliance of GaN, these radiation damage states deteriorate its ability to resist external compression. Meanwhile, these point defects lead the Debye temperature to decrease and thus increase the thermal expansion coefficients of GaN. As for the electronic properties of defective GaN, the point defects have various effects, i.e., VN (N vacancy), Gaint (Ga interstitial), Nint (N interstitial), and GaN (Ga occupying the N lattice site) defects induce the metallicity, and NGa (N occupying the Ga lattice site) defects decrease the band gap. The presented results provide underlying mechanisms for defect generation in GaN, and advance the fundamental understanding of the radiation resistances of semiconductor materials.

SIMULACIÓN DE LA INYECCIÓN DE UN HAZ NEUTRO EN TOKAMAKS CONTRIANGULARIDAD POSITIVA Y NEGATIVA

In this paper the dynamics of high energy charged particles in negative and positive triangularity tokamaks is through the simulation of a neutral beam injection on analytical MHD equilibria using the exact orbit code FOCUS. It is observed that the negative triangularity configuration presents fewer losses of non-thermal particles, and an energy deposition more localized than its counterpart.

Effects of High-Energy Electron Beam Irradiation on The Structure, Composition and Morphological Properties of Graphene Nanoplatelet Films

This work demonstrated the effects of 1.2 GeV high-energy electron beam irradiation on a few-layers of graphene (FLG) and multi-layer graphene (MLG) films grown via an in-house hot wire chemical vapour deposition (HWCVD) system. The FLG and MLG films were grown on highly doped n-type c-Si (100) substrates which were pre-treated using argon plasma (50 W) for 1 min and 10 min, respectively. The as-prepared samples were then irradiated using a 1.2 GeV high-energy electron beam with a dosage of 1.2 × 109 e-/cm2 at atmospheric and room temperature ambient conditions. The effects of the irradiation-mediated defects on the carbon lattice structure of both graphene samples were validated from the decreased sp2 C=C carbon content, and the increase in the adventitious carbon contamination C-O-C content. Raman results showed an elevation of the ID/IG ratio and blue-shift of the 2D and G band peaks for both the irradiated samples, which validated the mediated defects due to the dislocation of carbon atoms in the graphene sheets. The blue-shifted of 2D and G peaks were much more significant in the MLG than FLG which may indicate a better self-reconstructing property for the MLG atomic network, compared to the FLG. The stability of the films against high-energy electron beam irradiation was validated by their conductivity and surface topography. In conclusion, HWCVD grown graphene nanoplatelet films have high potential for graphene-based high-energy charged particle detectors.

Pion Detection Using Single Photon Avalanche Diodes.

We present the first reported use of a CMOS-compatible single photon avalanche diode (SPAD) array for the detection of high-energy charged particles, specifically pions, using the Super Proton Synchrotron at CERN, the European Organization for Nuclear Research. The results confirm the detection of incident high-energy pions at 120 GeV, minimally ionizing, which complements the variety of ionizing radiation that can be detected with CMOS SPADs.

Using and Testing Camera Sensors with Different Devices at Cosmic Ray Detection

Cosmic Ray (CR) is high-energy charged particles that reach the earth from space. CR detection methods and studies have been progressing rapidly since the beginning of the 20th century. One of these methods is the use of digital cameras with Charge Coupled Device (CCD) and Complementary Metal Oxide Semiconductor (CMOS) sensors. Mobile phone cameras or webcams offer an easily using and economical measurement system for CR measurement. The sensors are exposed to CR during a long exposure. CRs leave traces in the background. Cosmic particle tracks are then separated from the background noise and can be classified. Making the traces of the particles visible is important for understanding the subject. In this context, traces of particles such as electrons, muons, and alphas can be seen with the cloud chamber experiments. Help of sensor technology and cameras have developed in recent years, CR traces can be easily detected so that it can be seen. There are many software and international projects that detect CR using CMOS sensors in cell phone cameras. In this study, related projects, programs and studies were researched; CR traces that we captured with the help of Cosmic-Ray Extremely Distributed Observatory (CREDO) and Cosmic Ray Finder (CRF) software with web cam and a mobile phone cam CMOS sensor are presented. Links have been made about astrophysical events coinciding with previously detected particle images.

Gain measurements on NLGAD detectors

In the last few years, Low Gain Avalanche Detectors (LGAD) have demonstrated their outstanding performance when detecting high-energy charged particles. However, due to the difference in the multiplication mechanism for holes and electrons, the detection performance for low penetrating particles (e.g low-energy protons or soft x-rays) is significantly reduced. A novel design of an LGAD detector, the NLGAD, was designed and fabricated at CNM to overcome this drawback. A qualitative description of the NLGAD concept is presented in this work, along with gain response measurements of the first prototypes under visible light of 660 nm and 15 keV x-rays. Additionally, a review of the gain response under visible light of 404 nm and IR light of 1064 nm, previously studied, is also evaluated in this work. The results demonstrate that the NLGAD concept has the potential to detect low penetrating particles.

Hidden chamber discovery in the underground Hellenistic necropolis of Neapolis by muography

We report in this paper the muography of an archaeological site located in the highly populated “Sanità” district in the center of Naples, ten meters below the current street level. Several detectors capable of detecting muons - high energy charged particles produced by cosmic rays in the upper layers of atmosphere - were installed underground at the depth of 18 m, to measure the muon flux over several weeks. By measuring the differential flux with our detectors in a wide angular range, we have produced a radiographic image of the upper layers. Despite the architectural complexity of the site, we have clearly observed the known structures as well as a few unknown ones. One of the observed new structures is compatible with the existence of a hidden, currently inaccessible, burial chamber.

A Study on Degradation of Irradiated Insulating Materials used for Power Electronics

It is concerned that the recent expansion of the application environment of power electronics to high-altitude and/or high-radiation environments will cause deteriorations of insulation materials used in power electronics due to charging caused by cosmic ray irradiation. With respect to the high-radiation environments, the exposure of high-energy charged particles such as protons, electrons, etc. to the insulation materials gives rise to the charge accumulations, which dielectric BD (breakdown) of the materials and make the power electronics equipment inoperable, in the materials due to changes in the insulation characteristics of the materials. Therefore, in this paper, we report the feasibility study on the deteriorations of BD characteristics of three insulation materials (Alicyclic EP, OCN, PPS) due to proton or electron irradiation. As a result, it was found that BDE (BD electric field) of some insulation materials (Alicyclic EP, OCN) decreases due to proton or electron irradiation. The oxidation and the change in the electric field distribution in the materials caused by proton or electron irradiation may be one of the reasons for the decreases in BDE of the materials.

Effects of proton and oxygen ion irradiation on cardiovascular function and structure in a rabbit model

PurposeAstronauts on missions beyond low Earth orbit will be exposed to galactic cosmic radiation, and there is concern about potential adverse cardiovascular effects. Most of the research to identify cardiovascular risk of space radiation has been performed in rodent models. To aid in the translation of research results to humans, the current study identified long-term effects of high-energy charged particle irradiation on cardiovascular function and structure in a larger non-rodent animal model. Materials and methodsAt the age of 12 months, male New Zealand white rabbits were exposed to whole-body protons (250 MeV) or oxygen ions (16O, 600 MeV/n) at a dose of 0 or 0.5 Gy and were followed for 12 months after irradiation. Ultrasonography was used to measure in vivo cardiac function and blood flow parameters at 10- and 12-months post-irradiation. At 12 months after irradiation, blood cell counts and blood chemistry values were assessed, and cardiac tissue and aorta were collected for histological as well as molecular and biochemical analyses. Plasma was used for metabolomic analysis and to quantify common markers of cardiac injury. ResultsA small but significant decrease in the percentage of circulating lymphocytes and an increase in neutrophil percentage was seen 12 months after 0.5 Gy protons, while 16O exposure resulted in an increase in monocyte percentage. Markers of cardiac injury, cardiac troponin I (cTnI) and N-Terminal pro-B-type Natriuretic Peptide were modestly increased in the proton group, and cTnI was also increased after 16O. On the other hand, metabolomics on plasma at 12 months revealed no changes. Both types of irradiation demonstrated alterations in cardiac mitochondrial morphology and an increase in left ventricular protein levels of inflammatory cell marker CD68. However, changes in cardiac function were only mild. ConclusionLow dose charged particle irradiation caused mild long-term changes in inflammatory markers, cardiac function, and structure in the rabbit heart, in line with previous studies in mouse and rat models.

Applied Radiation Chemistry: Theory, Methods and Applications

Radiation chemistry deals with chemical processes initiated by the interaction of high-energy photons (X-rays) or charged particles (electrons, protons, alpha or heavy ions) with matter [...]

Corrections for regular identification of high energy positive particles in experimental data using lobachevsky space

In this work, high-energy positive charged particles are distinguished using the Lobachevsky space or Hyperbolic space, which is defined as the total rapidity multiplied by hyperbolic cosines of the transverse and longitudinal rapidity of the particles. Experimental data from eight different types of interactions detected in the bubble chambers accumulated in the high-energy sector were used in the calculations. The weights used to construct the proton and positive pion distributions for each of the interacting secondary particles have been eliminated, allowing such studies to be performed such as particle counting and clustering.These weights do not include calculated weights at azimuth angles, near the center of the star, or without momentum measurements. We now have the opportunity to study positive pions and protons. The percentage of confused particles increases with the beam energy.
 After the reconstruction, we conducted a study of the temperature of the charged particles produced by the p + p interaction of 205 GeV, where Tsallis temperatures are close to Hagedorn . On the other hand, Hagedor and temperatures are higher than Tsallis, which means that the unstable states exchange heat as they move to equilibrium.

Study of (p,2p) fission reactions in inverse kinematics using the R3B set-up

A new experimental fission approach is presented in the context of the R3B (Reactions with Relativistic Radioactive Beams) collaboration, at the GSI/FAIR facility, in which knockout reactions in inverse kinematics are used to induce fission of 238U that will allow to characterise the excitation energy of the fission process and all the fission products. The CALIFA (CALorimeter for In-Flight detection of γ-rays and high energy charged pArticles) calorimeter, a key part of the R3B set-up, is used to reconstruct the momenta of the two protons from the (p, 2p) reactions. Preliminary results show that kinematic variables and first estimates for nucleon-removal cross sections are well reconstructed and in good agreement with other experimental measurements.