Tungsten Anode Research Articles

Methodology study for determining the half-value layer using the Monte Carlo code PHITS

For most purposes, the quality of a beam can be specified in terms of the half-value layer (HVL), which is the thickness of material required to reduce the air kerma to half, at one meter from the source, from a unidirectional beam of infinitesimal width. Just like many other radiological quantities of interest, the HVL can be estimated via simulations employing the Monte Carlo Method (MCM). Among the variety of MCM based codes available, the Particles and Heavy Ions Transport Code System (PHITS) was the one adopted in this study. Primarily, simulations were conducted to determine the X-ray spectra resulting from the interaction of electron beams with different energies with a tungsten anode. Each of these spectra was then defined as a probability distribution for the photon source energies in a second round of simulations, where it was possible to estimate the X-ray beam qualities as specified by the reference literature. At this stage, it was possible to estimate the mean energy of the beam and the conversion coefficient for air kerma per unit fluence for each of the qualities. The results obtained in this phase were used to define the sources for other groups of simulations, where the air kerma was quantified for each source configuration, for different thicknesses of an aluminum metallic attenuator, which was also done with spectra for the same X-ray beam qualities obtained from a reference catalog. Curve fitting on the scatter of kerma points as a function of attenuation allowed the estimation of the HVL. The results obtained are consistent with the values described in the literature and demonstrate the efficiency of the developed methodology, as well as the use of the code in the evaluated energy range for X-rays.

Quantifying salivary iodine biomarker using total reflection X-ray fluorescence (TXRF): A method for assessing and monitoring iodine status simulated by Monte Carlo

Iodine stands as a vital trace element essential crucial for synthesizing thyroid hormones, which are essential for regulating metabolism and tissue growth. The “gold standard” for assessing iodine status in a population quantifies the iodine content in urine samples and is based on Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). Such method, or methods involving the readings of the Sandell-Kolthoff (SK) reaction, require complex sample preparations and the use of several toxic chemical elements. However, recent studies have shown a strong correlation between urinary iodine content (UIC) and iodine present in saliva. Using Monte Carlo simulations, this paper presents a TXRF-based method to quantify salivary iodine biomarker for assessing and monitoring iodine status. In the theoretical analysis, mono and polychromatic (filtered) excitation sources are considered. The detection and quantification limits of iodine, as well as the calibration curves for mass recovery, used the strong I Kα1 and I Kα2 lines. It was found that the optimal X-ray excitation source energy for iodine detection is 50 keV monochromatic X-rays. In contrast, using simulated spectra from a tungsten anode target, the best result was found at 70 kVp (peak voltage), after filtering the white beam with a copper absorber. Detection limits of iodine are 0.121 ng and 2.292 ng, for mono and polychromatic sources, respectively. The theoretical results of this paper show that TXRF could be a fast, simple and accurate alternative to ICP-MS or SK reaction-based methods. Of clinical significance, quantifying salivary iodine using TXRF to assess and monitor iodine status could be particularly helpful to patients undertaking 131I treatment. In addition, it could be used in epidemiological field studies to determine iodine deficiency/excess in children and pregnant women.

Study of mass transfer during electric spark processing of steel with tungsten anode material

Changes in the specific masses of electrodes were studied during electric spark processing of SCMnCr3 steel with anode material made of WP tungsten on an Alier-31 installation. Predominant erosion at high cathode processing energies is due to the difference in the melting/evaporation temperatures of the cathode substrate (iron) and anode (tungsten) materials. The influence of the energy of the electric spark discharge is associated with a change in the volume of the electrodes converted into liquid and gaseous states. The amplitude of the electrode-anode oscillations is influenced by changing the average volume of the interelectrode gap.

Influence of Thermionic Emission on He Ionization and Plasma Enhancement in Thermionic Energy Conversion

In this paper, the influence of thermionic emission on He ionization and plasma enhancement in thermionic energy conversion (TEC) are studied by experiment and numerical simulation. A 1D unsteady plasma TEC model, which includes a He ionization model, plasma conservation equations, and a thermionic emission formula for the wall, is developed. A He plasma thermionic energy conversion device composed of a barium–tungsten cathode and a tungsten anode is established. The volt–ampere curves of the He plasma TEC device are measured at 1050 K, 1150 K, 1250 K, 1300 K, and 1350 K temperatures. Both important cathode parameters, work function and emission area, are estimated. Based on the modelling simulation and the experiment, the He ionization mechanism in plasma TEC is discovered. The effects of cathode temperature on several distributions of plasma reaction rates, particle number density, and potential in He plasma TEC are described. Some important parameters, including electron mobility, resistivity, and plasma equilibrium are analyzed. The relationship of thermionic emission on plasma enhancement to the output power of plasma TEC is presented. The output powers of plasma TEC and vacuum TEC are compared at various cathode temperatures. A dimensionless analyzing method concerning thermionic emission intensity and plasma enhancement power is proposed. A brief dimensionless relationship is deduced regarding thermionic emission intensity and the plasma enhancement contribution of TEC. The principles and methods for quantitative calculations concerning the output power of plasma TEC under the action of thermionic emission are established. It is possible to do quantitative research on the effects of thermionic emission on plasma-enhanced TEC.

Effect of the Material of Electrodes on Electroformation and Properties of Memristors Based on Open Metal–SiO2–Metal Sandwich Structures

Memristors (elements of nonvolatile electrically reprogrammable memory) based on electro-formed open sandwich-metal-dielectric-metal (MDM) structures are fabricated using thin-film technology. Studies of the electroforming process and the features of the current-voltage characteristics (CVCs) after it was carried out for structures with various electrode materials showed that in the case of a tungsten anode, it was possible to minimize the probability of electrical breakdown during electroforming and subsequent oper-ation of the memory elements. This is valid for any position of the anode in the MDM structure: both upper and lower. However, it is experimentally shown that tungsten is not the optimal material. The production of the anode from molybdenum retains all the advantages of the design with tungsten, and in addition, it leads to a noticeable decrease in the electroforming voltage, which can increase the reliability of this process. The results obtained can be used to optimize the design of the memory element.

Experimental study of stability and pollutant emissions of turbulent biogas flames under microsecond pulsed plasma

Biogas is a mixture of methane (50–80%.vol), carbon dioxide (20–45%.vol), and in smaller proportions of N2, O2, H2S, and NH3. For a high rate of CO2 in the biogas, the combustion can generate strong instabilities and the flame can be very lifted from the burner and even blown. To overcome these problems of instabilities and flame extinction, the use of a microsecond pulsed plasma is considered for this study. This study aims to characterize the effects of microsecond pulsed discharges on the stabilization and emission characteristics of non-premixed swirling biogas/air flames at different operating conditions of combustion (CO2 rate, power, and equivalence ratio) and plasma (pulse repetition frequency and input electrical voltage). The plasma is performed above a coaxial burner with a swirler of the oxidizer. It is generated by a DC-pulsed power generator with a high voltage (HV) pulse duration of a few microseconds. The burner consists of two concentric tubes and a central metal rod used as a cathode for the plasma. The outer tube contains a swirler and supplies the oxidant flow, and the inner tube delivers the fuel (methane, biogas) around the central metal rod. High voltage pulses are applied on two anode tungsten wires that are symmetrically arranged from either side of the cathode to obtain two plasma zones in the stabilization region of the flame. The burner is placed in a parallelepiped combustion chamber with a volume of 100x48x48 cm3. Mass flow rates of air and fuel are regulated by thermal mass flow controllers (Brooks SLA5851S). OH* chemiluminescence measurements are done to describe the structure and the flame stability throughout the lift-off heights (Hf) variation. Results showed that plasma generated by microsecond HV pulses can improve flame stability by decreasing its Hf especially at low fuel velocities. In this regard, the optical emission spectra (OES) were visualized. The results reveal that the pulsed plasma generates chemically active species such as excited N2*, CH*, OH* molecules, and H* atoms, leading to improved flame stability. Their intensities' dependence on the pulse repetition frequency, the sight position of the OES, the concentration of CO2 in the fuel, and the fuel velocities were investigated in detail. Furthermore, the NOx and CO emissions in the burned gas are investigated over a wide range of repetition pulse frequencies. It is seen that the microsecond pulsed plasma slightly increases the NOx emission and reduces CO concentration in the flue gases.

Improvement approach for determination of cadmium at trace levels in soils by handheld X-ray fluorescence analyzers

Determining trace levels of cadmium in soils by the handheld X-ray fluorescence analyzer is severely hampered by the spectrum baseline. To improve the peak-to-background ratio of the characteristic Cd-Kα X-ray, the filter structure, material, and thickness were optimized; to find the most informative variables for the PLS analysis of trace Cd, the related information enhancement competitive adaptive reweighted sampling (rieCARS) was proposed as a variable selection approach, which contains correlated spectral selection (CSS), double logarithmic processing(DLP), competitive adaptive reweighted sampling (CARS). To eliminate the interference of the K-series line of the Ag anode target on trace Cd, the X-ray tube was used with the Tungsten anode target. One combined filter containing a 0.4 mm thickness Cu and a 0.5 mm thickness Fe was selected, which was placed between the X-ray tube and the sample. The instrumental limit of detection for the Cd descended from 32 mg/kg to 0.02 mg/kg . Sixty-four soil samples were used to establish the model for the filtered signal. The model was compared with PLS, CARS+PLS, DLP + CARS+PLS, CSS + PLS, and CSS + CARS+PLS. The application of rieCARS improved the performance of the calibration model for trace Cd. The coefficient of determination R2 of the rieCARS+PLS model on the calibration set was 0.990; the RMSEP on the test set was 0.28 mg/kg; the average of the relative error in the Poyang Lake soil samples was 0.18; the relative standard deviation for the thirteen replicates of the GSD17 was 0.07. The developed analytical procedure will lay the foundation for the analysis of heavy metal pollution sources in soils and ecological sustainability assessment.

Decomposition of SF6 by a plasma focus device

Decomposition of SF6 by a low energy plasma focus (PF) device has been investigated. The PF device performance in SF6 atmosphere was weaker than other gases such as argon, methane and nitrogen. Tungsten and vanadium anode tips were employed to generate thin layers of deposited products on substrates with different number of focused shots in SF6 atmosphere. The proper choice of the anode tip and substrate material has a direct effect on SF6 decomposition and generation of desire products. Free fluorine atoms and ions are produced during discharges that react with housing chamber and corrode the device materials such as Pyrex insulator, 304 stainless steel chamber and many more. Field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX), grazing incidence X-ray diffraction (GIXRD) and X-ray photoelectron spectroscopy (XPS) were utilized to identify the deposited solid film products.

Simulation and Optimization of Optical Fiber Irradiation with X-rays at Different Energies

We investigated the influence of modifying the voltage of an X-ray tube with a tungsten anode between 30 kV and 225 kV, and therefore its photon energy spectrum (up to 225 keV), on the Total Ionizing Dose deposited in a single-mode, phosphorus-doped optical fiber, already identified as a promising dosimeter. Simulation data, obtained using a toolchain combining SpekPy and Geant4 software, are compared to experimental results obtained on this radiosensitive optical fiber and demonstrate an increase of the deposited dose with operating voltage, at a factor of 4.5 between 30 kV and 225 kV, while keeping the same operating current of 20 mA. Analysis of simulation results shows that dose deposition in such optical fibers is mainly caused by the low-energy part of the spectrum, with 90% of the deposited energy originating from photons with an energy below 30 keV. Comparison between simulation and various experimental measurements indicates that phosphosilicate fibers are adapted for performing X-ray dosimetry at different voltages.

PEPI Lab: a flexible compact multi-modal setup for X-ray phase-contrast and spectral imaging

This paper presents a new flexible compact multi-modal imaging setup referred to as PEPI (Photon-counting Edge-illumination Phase-contrast imaging) Lab, which is based on the edge-illumination (EI) technique and a chromatic detector. The system enables both X-ray phase-contrast (XPCI) and spectral (XSI) imaging of samples on the centimeter scale. This work conceptually follows all the stages in its realization, from the design to the first imaging results. The setup can be operated in four different modes, i.e. photon-counting/conventional, spectral, double-mask EI, and single-mask EI, whereby the switch to any modality is fast, software controlled, and does not require any hardware modification or lengthy re-alignment procedures. The system specifications, ranging from the X-ray tube features to the mask material and aspect ratio, have been quantitatively studied and optimized through a dedicated Geant4 simulation platform, guiding the choice of the instrumentation. The realization of the imaging setup, both in terms of hardware and control software, is detailed and discussed with a focus on practical/experimental aspects. Flexibility and compactness (66 cm source-to-detector distance in EI) are ensured by dedicated motion stages, whereas spectral capabilities are enabled by the Pixirad-1/Pixie-III detector in combination with a tungsten anode X-ray source operating in the range 40–100 kVp. The stability of the system, when operated in EI, has been verified, and drifts leading to mask misalignment of less than 1 upmum have been measured over a period of 54 h. The first imaging results, one for each modality, demonstrate that the system fulfills its design requirements. Specifically, XSI tomographic images of an iodine-based phantom demonstrate the system’s quantitativeness and sensibility to concentrations in the order of a few mg/ml. Planar XPCI images of a carpenter bee specimen, both in single and double-mask modes, demonstrate that refraction sensitivity (below 0.6 upmurad in double-mask mode) is comparable with other XPCI systems based on microfocus sources. Phase CT capabilities have also been tested on a dedicated plastic phantom, where the phase channel yielded a 15-fold higher signal-to-noise ratio with respect to attenuation.

Рентгенолюминесценция нанопорошков SrF-=SUB=-2-=/SUB=-: Eu

Concentration series of single-phase SrF2:Eu solid solutions with a particle size of ≈50 nm were synthesized by precipitation from aqueous solutions. The bands of europium in the di- and trivalent states as well as a band of intrinsic exciton luminescence of strontium fluoride were identified in the X-ray luminescence spectra. The most intense luminescence band is the band of trivalent europium with a maximum at 585–590 nm which corresponding to the 5D0 →7F1 transition. The highest X-ray luminescence intensities upon excitation by an X-ray tube with silver and tungsten anodes are achieved for compositions containing about 15.0 mol.% and 7.5 mol.% europium, respectively.

First characterization results of ARCADIA FD-MAPS after X-ray irradiation

The ARCADIA collaboration is developing fully-depleted (FD) Monolithic Active Pixel Sensors (MAPS) in a 110 nm CMOS process in collaboration with LFoundry. The sensor design incorporates an n+ collection node within a n-type epi-layer on top of a high-resistivity n-type substrate and p+ backside. Thus, the pn-junction sits on the backside and through an applied backside bias, the full substrate gets depleted. The targeted applications of this technology range from future high energy physics experiments to space applications, and medical and industrial scanners. Together, these applications set the minimum requirements on the detector: data collection at hit rates of (10–100) MHz/cm2, full signal processing within (1–10) μs, maximum power consumption (5–20) mW/cm2 and radiation tolerances of up to 3.4 Mrad or 6.2 × 1012 1 MeV neutron equivalent fluence. In order to proof the performance of the technology, a demonstrator chip of 512 × 512 pixels with 25 μm pitch was designed and fabricated in a first engineering run in 2021, together with additional test structures of pixel and strip arrays with different pitches and sensor geometries. The production run has produced functional passive and active pixel matrices. Earlier studies have shown that positive oxide charges and traps at the Si-SiO2 interface, introduced by ionising radiation, affect the depletion region around the collection electrode, increasing the pixel capacitance. By varying the gap size between collection node and pwells, the geometry can be optimised to keep the capacitance low also after irradiation. To study the performance after irradiation, of the optimised diode designs, the passive pixel matrices were irradiated with doses up to 10 Mrad (SiO2) using a X-ray tube with a Tungsten anode. The measurements are complemented by TCAD simulations. The maximum capacitance increase after irradiation was found to reach 6 and 12 fF/pixel for pixel pitches of 25 and 50 μm, respectively. The relative capacitance increase after irradiation has hereby been found to reach up to 250% after a dose of 10 Mrad.

Measurement of Average Glandular Dose Using Multiparameter X-ray Measuring Instrument

The average glandular dose (AGD) is very important in the quality control of mammography. The AGD calculation requires measurements of half-value layer (HVL) and entrance surface air karma (ESAK). The HVL is measured by the Al-attenuation method using a non-energy-dependent ionization dosimeter. As the Al-attenuation method performs measurements using a succession of added filters, it requires lots of X-ray exposure and measurement time. In recent years, measuring instruments that can measure tube voltage, irradiation time, exposure dose, HVL, and other factors, at the same time, using one shot of X-rays have been developed. In this study, measurement of the AGD using multiparameter X-ray measuring instrument about rhodium (Rh) and tungsten (W) anode X-ray tubes. A comparative study was performed using standard ionization dosimeters. The error in measurements was as follows: HVL 5.8%, ESAK 3.3%, and AGD 2.9%. The AGD measurement using a multiparameter X-ray measuring instrument is simple and can significantly reduce the measurement time while maintaining accuracy.

Experimental demonstration of ultrahigh sensitivity Talbot-Lau interferometer for low dose mammography

Objective. Even though the techniques used for breast cancer identification have advanced over the years, current mammography based on x-rays absorption, the ‘gold standard’ screening test at present, still has some shortcomings as concerns sensitivity and specificity to early-stage cancers, due to poor differentiation between tumor and normal tissues, especially in the case of the dense breasts. We investigate a possible additional technique for breast cancer detection with higher sensitivity and low dose, x-ray phase-contrast or refraction-based imaging with ultrahigh angular sensitivity grating interferometers, having several meters length. Approach. Towards this goal, we built and tested on a mammography phantom, a table-top laboratory setup based on a 5.7 m long Talbot-Lau interferometer with angular sensitivity better than 1 μrad. We used a high-power x-ray tungsten anode tube with a 400 μm focal spot, operated at 40 kVp and 15 mA with a 2 mm aluminum filter. Main results. The results reported in our paper confirm the ultrahigh sensitivity and dose economy possible with our setup. The visibility of objects simulating cancerous formations is strongly increased in the refraction images over the attenuation ones, even at a low dose of 0.32 mGy. Notably, the smallest fiber of 400 μm diameter and calcifications specs of 160 μm in diameter are detected, even though the spatial resolution at the object of our magnification M ∼ 2 setup with a 400 μm source spot is only ∼250 μm. Significance. Our experiments on a mammography phantom illustrate the capabilities of the proposed technique and can open the way toward low-dose interferometric mammography.

Study of the performance change in digital mammography systems depending on the total number of examinations

Digital mammography equipment should operate at a high-performance level for detecting breast cancer over the lifetime of the systems. This study investigates the performance of the Fujifilm Amulet Innovality full-field digital mammography system in relation to the number of exposures. The performance of twelve systems, from new and up to 17 000 examinations, was compared. The x-ray output, half-value layer (HVL), contrast-detail (C-D) detectability, contrast-to-noise ratio (CNR), mean glandular dose (MGD), signal transfer property (STP), pre-sampled modulation transfer function (MTF), normalized noise power spectra (NNPS), detective quantum efficiency (DQE) tests were performed to determine the performance change. The noise sources were also analyzed in the spatial domain. The x-ray output and HVL values at 28 kV with tungsten anode and rhodium filter were 15 μGy/mAs ± 1.0 (coefficient of variation (cov) = 7.0%) and 0.54 mmAl ± 0.008 (cov = 1.5%), respectively. The average MGDs for 60 mm equivalent breast to reach the achievable image quality level for 0.1 mm and 0.25 mm detail diameters of circular discs on the CDMAM 3.4 phantom image were 1.17 mGy ± 0.13 (cov = 11%) and 1.40 mGy ± 0.09 (cov = 6%), respectively. The average MGD for 53 mm equivalent breast was 1.08 mGy ± 0.14 (cov = 13%) at dose setting Normal in automatic exposure control (AEC) mode. All tested devices demonstrated good linearity with R2 ≥ 0.999 in the STP curves. The average MTF at 5.0 mm−1 spatial frequency was 0.66 ± 0.007 (cov = 1.0%). The average NNPS was 2.38 × 10−6 mm2 ± 2.13 × 10−7 (cov = 9.0%) at 5.0 mm−1. The average DQE value at 5.0 mm−1 was 0.33 ± 0.02 (cov = 5.0%), and the mean peak DQE was 0.66 ± 0.03 (cov = 5.0%). The mean power coefficient (b), determined from the power relationship between linearised standard deviation and detector dose while analyzing noise sources, was 0.49 ± 0.007 (cov = 1.4%). There was no gradual change in the x-ray tube and detector performance by the number of exposures, and taking up to 68 000 images did not decrease the quality of the systems.

THE CONCENTRATION EFFECT OF K2SO4 ELECTROLITE SOLUTION ON GLOW DISCHARGE PLASMA ELECTROLYSIS

Plasma electrolysis is currently an environmentally friendly technology that is used as an alternative to nitrogen fixation, clean water treatment, batik waste degradation and the synthesis of other compounds. The success indicator of plasma electrolysis technology is seen from the formation of glow discharge. One of the factors that influence the formation of plasma in this method is the electrolyte solution. The electrolyte solution used in this study is K2SO4 because its conductivity causes electron jumps. This study aims to determine the effect of various concentrations of K2SO4 electrolyte solution on glow discharge plasma at the anode.In the plasma electrolysis reactor with stainless steel cathode and tungsten anode and 0.01 M electrolyte solution; 0.02 M; and 0.03 M K2SO4. The formation of glow discharge plasma occurs at the anode. Changes in concentration affect the critical voltage (VD) where the higher the concentration (0.03 M), glow discharge occurs at a lower voltage (600 V). This is due to the presence of high dielectric strength in the solution causing lower discharge strength to occur in solutions with lower electrolyte concentrations.Keywords: anode, plasma electrolysis, K2SO4 electrolyte, glow discharge

Measured low-energy x-ray spectra of interest in diagnostic radiology and mammography

Objective. In cities situated at high-altitude, the measured x-ray spectra are required to calculate the absorbed dose to water in radiobiology and medical dosimetry because of the air-density effect. This work aims to measure, in a high-altitude city, a set of x-ray spectra from an x-ray tube with tungsten anode generated at potentials of the M-series x-ray beams from NIST in the range of 20 and 150 kV as well as other beam qualities that have been characterized and used for dosimetry study in our group called W-series. To also measure some spectra of mammography interest in the energy range of 25 and 35 kV using additional filtration of rhodium (Rh), molybdenum (Mo) and silver (Ag). Approach. A tungsten anode x-ray tube with potential between 10 to and 160 kV was used. A high-purity germanium (HPGe) detector associated with a DSPEC Jr 2.0TM digital signal processing module has been used for the spectra measurements. Prior the spectra measurements, the HPGe detector has been characterized and calibrated using several radioactive sources. Main results. The M80 spectrum was compared to a mathematically filtered beam from Physicalisch Technische Bundesanstalt corresponding to the same potential finding a difference of 0.7% in the average energy. So, the mathematically filtered beam from PTB matches very well our M80 beam. The beams M80, M100 and M120 were also compared with calculations for the corresponding kilovoltage from an executable that calculates x-ray spectra from tungsten anode x-ray tubes in the energy range between 40 to 300 kV called SpekCalc. The SpekCalc reproduces qualitatively the experimental spectra, but not quantitatively, mainly for M100 and M120 beams. Significance. These spectra can be used to simulate the patient dose as well as image quality using Monte Carlo (MC) codes or to evaluate the absorbed dose in dosimetry studies

(Invited, Digital Presentation) Detailed Chemical Modeling of Solid Electrolyte Interphase Growth and Evolution

The solid electrolyte interphase (SEI) is a layer that forms at the anode-electrolyte interphase in lithium ion batteries. The layer forms due to voltage instability of the electrolyte at low anode potentials, but serves to passivate the electrolyte to protect against further uncontrolled decomposition. In theory, the SEI is self-limiting, but in reality, continued growth over the battery’s lifetime leads to capacity fade, poor rate capability, and eventually cell death. Though significant progress in recent years has improved the SEI’s function and stability, poor understanding of its most basic chemistry impedes “rational design” of SEI layers for advanced battery applications. Understanding and quantifying the elementary chemistry of the SEI is made challenging by the layer’s thickness (10s to ~100 nm), chemical sensitivity, mechanical fragility, and complex chemistry (upwards of 100 reactions have been proposed). For these reasons, These factors combine to make studying the fundamental chemistry of SEI growth and evolution a significant challenge. Both the computational tools to model the SEI’s complex chemistry and the experimental data required to validate such models are all too rare.This talk will provide an overview of recent efforts to model the fundamental electrochemistry of SEI growth and evolution. The simulations are based on a continuum-scale, finite-volume framework, and leverage the open-source software package Cantera to enable efficient simulation of arbitrarily complex electrochemical mechanisms. Simulation results, as in Figure 1, are validated against two operando measurements of the SEI grown on a non-intercalating tungsten anode: depth profiling via neutron reflectometry (NR), and SEI mass uptake data via quartz crystal microbalance with dissipation (QCM-D) taken during cyclic voltammetry cycling. Interrogation of the detailed model results provide insights into the complex phenomena controlling initial SEI growth, and validation against NR and QCM-D data identify prominent reaction pathways and key chemical species present in the SEI. Finally, we will conclude by discussing future steps, includuing transferring mechanistic insights to new scales, geometries, and chemistries, and coupling models with inputs from atomistic simulations. Figure 1

Multichannel AlGaN/GaN Schottky Barrier Diode with Low Turn‐On Voltage and On‐Resistance

Herein, multichannel AlGaN/GaN Schottky barrier diodes (SBDs) with recess structure and tungsten (W) anode are proposed. The multichannel heterostructure improves the current drive capability of the devices and achieves a lower forward voltage (V F). W anode reduces the turn‐on voltage (V ON) due to its lower work function and direct contact with all 2D electron gas (2DEG) channels in the recessed area. Post anode annealing is utilized to improve the interface between the metal and GaN etching surface. The fabricated devices with a 6.5 μm anode–cathode distance (L AC) achieve an ultralow V ON of 0.29 V, V F of 0.69 V, and a low on‐resistance (R ON) of 2.39 Ω mm. The capacitance effect of multichannel heterostructures has been analyzed via the capacitance–voltage characteristics, showing the great potential of multichannel AlGaN/GaN SBDs for high‐frequency applications.

ANALYSIS OF OBTAINING AN IMAGE WITH THE TOMOGRAPH

CT scans vary from manufacturer to manufacturer. There are several generations of CT. The concept of CT generation is not so much related to the time of its birth, but to the use in the scanner of the type of motion of the emitter-detector system. The generation number (first, second, third, fourth, etc.) is related to the type of tube-detector system design. Three types of scanners are now available: third, fourth and fifth generation. The life of the first generation of CT was fleeting: the duration of the scan did not suit – about 20 minutes. and the computer reconstruction of the image took too long. Only the brain could be examined on such devices. As for the human body, the image turned out blurry, blurred. But the process of improvement continues. Today, research is being conducted on fourth- and fifth-generation devices. They have not one, but many X-ray emitters, up to 200. It uses a very powerful processor with high-speed information processing – up to 10 million operations per second. As a result, the scan time was reduced to 40-50 milliseconds. It is now possible (here is a scientific idea!) To see on the telemonitor the reduction of certain transverse layers of the heart 1-2 millimeters thick. At spiral CT in the course of research with simultaneous constant rotation of system “tube – detectors” the table constantly moves and thus there is a spiral movement of a fan-shaped beam through a patient’s body. Spiral CT makes it possible to examine the anatomical region in one period of respiratory arrest, and the thickness of the reconstructed layer is not related to the original width of the tomogram. Obtaining thin conjunctival sections, which are tightly arranged in a spiral, allows you to get three-dimensional reconstructions. In combination with intravenous bolus contrast and subtraction data processing, CT angiograms can be obtained, which reproduce images of large vessels. In recent years, multispiral (multislice) CT has been used, which is based on the principles of imaging as in spiral CT, but due to multi-row detectors for full rotation of the system “tube detectors” can display more than one slice (currently from 2 to 16 images). This has made it possible to perform studies of the heart, study a large anatomical area, such as the lungs, thin sections in one breath hold, and significantly improve the quality of multiplanar and three-dimensional reconstructions. In electron beam tomography, the source of X-rays is a large electron gun with several massive parallel anode targets located in semiconductor rings around the patient. The intense anode beam is directed along the tungsten anode rings. The electron beam thus obtained passes through the patient’s body and is received by a fixed array of detectors. This achieves a high tomography rate, which is sufficient for the study of a moving heart: clearly delineated images can be obtained without the use of synchronization with the ECG. With the help of electron-beam tomography it is also possible to perform CT angiography and construction of high-quality three-dimensional reconstructions. Thus, modern medicine is impossible without CT. For example, in neurology, computed tomography, in addition to skull bones, well identifies the ventricles of the brain, venous sinuses, subarachnoid cisterns, interhemispheric fissure, cortex, basal nodes, inner capsule, trunk, cerebellum and other structures. The radiation load does not exceed the level usual for X-ray examination. At the same time, CT scans provide 100 times more information about the brain than conventional skull x-rays. But its importance is not limited to use only for the diagnosis of various diseases. Under the control of CT perform punctures and directed biopsy of various organs and pathological foci. The role of CT in the control of conservative and surgical treatment of patients is extremely important. CT is a valuable method of accurate localization of tumors and directing the radiation source to the focus when planning radiation treatment of malignant tumors.