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In this work, we studied the size quantization effects in the channel of a low dimensional MOSFET using a Self-Consistent Quantum Method where Schrodinger-Poisson equations are solved for determining the electron density for 3nm × 3nm and 12nm×12nm 2D channels. The 3nm×3nm channel MOSFET show the peak of the electron density at the middle whereas the 12nmξ12nm channel MOSFET shows the accumulation of the electrons at the oxide/semiconductor interface. The electron density in the channel is obtained using density matrix formalism from the density matrix [ ρ ]=[ 1/(1+exp(β(H−μ))) ]. A block diagonal Hamiltonian Matrix [H] is constructed for the oxide/channel/oxide 2D structure for the dual gate MOSFET. This structure is discretized and Finite-Difference method is used for constructing the matrix equation. We also show the effect of effective mass on the overall channel electron density distribution. This analysis is very important and gives an understanding of the Physics of the channel electron density for Nano-Scale Devices

Malaysia Youth Satellite (MYSat) is a scientific 1U CubeSat initiated by School of Aerospace Engineering Universiti Sains Malaysia (USM) in 2016. The objective of the MYSat mission is to measure accurate electron density and temperature in E-layer of the ionosphere by a CubeSat. This mission was driven from a study which reported that Earthquake precursors could be analyzed from the ionosphere. Electron temperature and density probe (TeNeP) was the selected scientific instrument for MYSat. This instrument develops a technique by measuring the shift of electric floating potential (ΔVf) characteristics of an electrode immersed in plasma. The ΔVf characteristic of the plasma will then be retrieved from the instrument where the plasma’s electron density (ne) together with the temperature (Te) can be acquired. The TeNeP instrument has been proven not affected by the satellite potential variation effects, which is a common problem for electron measurements onboard small satellites, especially CubeSats. Therefore, the accurate Te and ne measured by MYSat could contribute to the on-going research regarding ionospheric physics and possible Earthquake precursor effects. An already developed TeNeP circuit based on a 2U platform has been redeveloped for MYSat’s 1U based platform. In this paper, several performance tests to the TeNeP generator circuit in the preparation of the MYSat will be shown and discussed.

In this paper the method of the density functional theory in the local electron density approximation with allowance for strong correlations in the d-shell of the noble metal ion (LDA+U method) calculations are performed of the band structure, the partial densities of electronic state and optical functions: dielectric permeability, refractive index, reflection and absorption coefficients of Ag7SiS5I crystal. According to the calculation results Ag7SiS5I is a indirect-gap semiconductor with the calculated energy of the band gap Egicalc=1.73eV. The analysis of partial contributions into the density of electronic states allowed to identify the genetic origin of different subbands of the valence band, and also to obtain the formation of a chemical bond in the crystal under study. The most important feature of the electronic spectrum of the Ag7SiS5I crystal is the presence of an intense peak in the density of states N(E) formed by Ag4d-like zone. The calculated spectral dependences of the absorption and reflection coefficients show the main features of the e2(ω) dependence, and the maxima of the energy distribution of the refractive index practically coincide in position with the centers of gravity of the bands of the real part of the complex permittivity.

This article briefly reviews the impact of parameters, such as, angle of incidence, applied magnetic field, electron density, and thickness ratio, on the band structures of a magnetized cold plasma photonic crystal considering different sets of chosen values of these parameters. We observe a simultaneous enhancement in the two obtained photonic bandgaps with increase in the electron density as well as incident angle and there is a shifting in the band positions, where lower band edge for first wider photonic bandgap is found to be more sensitive in comparison to higher band edge. It is noticed that, on increasing the applied magnetic field strength as well as thickness ratio, the first bandgap decreases with a significant shifting in lower band edge as compared to higher band edge. However, the second narrow forbidden gap shows reverse behaviour in its width with thickness ratio. Thus, these four parameters act as controlling factors for both width and location of the photonic bands in a 1-D magnetized plasma PhC. The obtained results are also in a good agreement with those previously investigated by many researchers with such extrinsic PhCs. Hence, the article provides some important insights for designing tunable broadband reflectors in the GHz frequency regions for microwave devices.

A plasma model was established to calculate the discharge properties during TaN and TiN sputter deposition at low pressure conditions (about 2 mTorr). The plasma model is zero dimensional and includes major reactions between electrons and argon/nitrogen gases. The gas flow rates are varied for nitrogen (up to 9 sccm) and always 10 sccm for argon. The calculated electron temperature increases from 4.15 to 4.35 eV at 370 W magnetron power. The predicted electron density is about 109 cm−3, and increases with nitrogen flow rate. The predicted electron temperature and density values agree well with measurements for plasma at similar power level and pressure conditions. As nitrogen flow rate increases, the N atom and N2* densities both increase linearly, at the order of 1011 cm−3.

The quantum mechanical effects has wide applications in quantum plasma echoes, quantum plasma instabilities and microelectronics devices. Quantum effects may become important when the electron number density of the order of 1030 m−3 andsmall temperatures of a few thousand Kelvin. A dusty plasma is a three-component plasma consisting of electrons, ions, and a solid grains. We use the quantum hydrodynamic model to derive the plasma dispersion equation to study the growth rate of electron drift waves in quantum dusty plasmas. The growth shows depends on the electron temperature, electron density, electron drift velocity and wave number, ions and dust mass. The results may be useful to understand the physics of dense astrophysical objects. Different approximations are tried to solve the dispersion equation.

We are developing the acoustic levitation diffractometer, a new container-free diffractometer at the Swiss Light Source, Paul Scherrer Institut. By rotating single crystals in an acoustically levitated droplet and collecting the diffraction images by a fast-frame-rate X-ray image detector, the data collection can be completed within a few hundred milliseconds or shorter at room temperature. Here we report time-lapse measurements of ligand soaking using a single crystal. This was achieved by collecting a series of datasets after soaking ligand solution into single lysozyme crystals in a levitated droplet in the acoustic cavity of the diffractometer. Electron density maps of the lysozyme crystals obtained every 30 seconds after the ligand soaking showed meaningful conformational changes around the binding site of the ligand and the radiation damage for 300 seconds after the ligand soaking.

In this study, we have carried out the experimental observation and modeling of negative ion, atomic and molecular ions in hydrogen sheet plasma. On the experiment, hydrogen sheet plasma was produced by a linear plasma device TPD-Sheet IV. The electron density and temperature were measured by Langmuir probe. The density profiles of hydrogen ions were measured by omegatron mass spectrometer. In the experimental result, it has been found that negative ions are produced at periphery region of sheet plasma. When the hydrogen gas pressure was 0.2-0.3Pa, negative ion density became maximum (NH− ∼1017 m−3). To model the ion density in this experiment, a zero-dimensional model is developed for solving the system of rate balance equations for ion and gas species. In evaluating the rate coefficients, the reactions involving H+, H2+, H3+, and H- are vibrationally resolved in the model. In the calculate result, it has been found that negative ions are produced at periphery region of sheet plasma. When the hydrogen gas pressure was 0.2-0.3Pa, negative ion density became maximum (NH− ∼1016 m−3). The experiments and the model calculate results indicate that production of negative ions in sheet plasma depends on the gas pressure and location from the plasma column.

A quartz-chamber 2.45 GHz ECR ion source is designed at Peking University (PKU) for the application of plasma diagnosis [Patent Number: ZL 201110026605.4]. In this work, spectra of this ion source, which operate under different gas pressure and different RF power, are acquired with a high resolution spectrometer. The collision radiative (CR) model and line intensity ratio method are chosen for the plasma parameters diagnosis inside the discharge chamber during the plasma generation processes. The electron temperature and electron density are obtained based on the line ratio of noble gas. The dissociation degree of hydrogen is measured with the line ratio of hydrogen. At last, the plasma processes are discussed based on the diagnostic results and the performance of the cluster ion source at PKU.A quartz-chamber 2.45 GHz ECR ion source is designed at Peking University (PKU) for the application of plasma diagnosis [Patent Number: ZL 201110026605.4]. In this work, spectra of this ion source, which operate under different gas pressure and different RF power, are acquired with a high resolution spectrometer. The collision radiative (CR) model and line intensity ratio method are chosen for the plasma parameters diagnosis inside the discharge chamber during the plasma generation processes. The electron temperature and electron density are obtained based on the line ratio of noble gas. The dissociation degree of hydrogen is measured with the line ratio of hydrogen. At last, the plasma processes are discussed based on the diagnostic results and the performance of the cluster ion source at PKU.

Ion implantation requires a high beam current stability to ensure a uniform implantation dose across the wafers. This requires ion sources with a stable extraction system to achieve a high beam current stability. Our goal is to extract 0.5 mA of C2- with less than 10 glitches per hour, with a glitch defined as any variation greater than +/- 5% of the nominal beam current. The beam energy should be between 10 keV and 30 keV while the normalized 4 RMS emittance should be less than 1 mm·mrad. We’ve shown that high negative carbon ion current densities could be obtained with a multi-cusp ion source when acetylene was used as the feed gas (0.27 mA of C2-), but there was significant sparking between the electrodes, which led to frequent beam current glitches (>1000/hour). In this study, we investigate the different factors that contribute to the sparking between the electrodes. We found that the sparking is highly correlated to the dumping of the co-extracted electrons and the beam strike on the electrodes. Extraction simulations were completed to determine how the electron dumping can be improved and how the beam strikes on the electrodes can be reduced. Furthermore, we modified the magnetic configuration in the plasma chamber to decrease the electron density close to the extraction aperture, which reduced the co-extracted electron current by a factor of almost 5 and reduced sparking frequency to about 20 glitches per hour. However, there was a corresponding decrease in the extracted beam current due to the smaller aperture sizes needed to reduce the sparking, with only 0.05 mA of C2-.

An experimental technique is presented for studying two-dimensional (2D) ideal fluid vortices in the presence of externally imposed flows, using an electron plasma confined in a Penning-Malmberg trap. This procedure is made possible by an isomorphism between the Drift-Poisson equations governing electron plasma dynamics and the 2D Euler equations describing an ideal fluid. Here, the electron density is the analog of fluid vorticity, and the electric potential that of the fluid stream function. External flows are imposed in 2D using a segmented electrode spanning the length of the plasma. Details of the experimental procedure and data analysis are given, including the capabilities and limitations of the experimental approach.

Argon plasma behavior in a 2.45 GHz electron cyclotron resonance (ECR) plasma source is studied by means of the finite element software COMSOL. The ECR plasma is simulated in two stages. First, the static magnetic field, produced by three solenoids and a set of Halbach permanent magnets, is simulated in a stationary study. This field is then used to simulate the properties of an on-resonance microwave plasma. Our first results including magnetic field distribution, electron density, Argon ion density and microwave power absorption are presented.

For an unique experimental approach to study low-energy electron transport in a plasma, a “sub” filament was introduced in a volume-produced, DC filament-driven hydrogen negative ion (H−) source as an additional electron source. The sub-filament engages in the special task which introduces additional electrons into the plasma with controlling injection energies. Transports of the additional electrons are observed by the difference of the electron density profiles with and without the electron introduction. The experimental result here indicates that the electron transport is strongly restricted by the filter magnetic field. On the other hand, analysis with Particle-In-Cell simulation seems to imply that the restriction by the magnetic field can be changed by the controlling electron energy in the sub-filament experiments for the research of the electron transport.For an unique experimental approach to study low-energy electron transport in a plasma, a “sub” filament was introduced in a volume-produced, DC filament-driven hydrogen negative ion (H−) source as an additional electron source. The sub-filament engages in the special task which introduces additional electrons into the plasma with controlling injection energies. Transports of the additional electrons are observed by the difference of the electron density profiles with and without the electron introduction. The experimental result here indicates that the electron transport is strongly restricted by the filter magnetic field. On the other hand, analysis with Particle-In-Cell simulation seems to imply that the restriction by the magnetic field can be changed by the controlling electron energy in the sub-filament experiments for the research of the electron transport.

Pure and Ag-loaded NaNbO3 were synthesized, and characterized by PL, Raman, XRD and FE-SEM. They were subsequently applied for the photocatalytic CO2 reduction to fuels process, wherein methanol and formic acid were detected. Loading silver significantly enhanced the methanol product selectivity over that of formic acid, which is economically-favorable since methanol is an energy-dense value-added fuel. We hypothesize that silver acts as an electron-trapping centre, which increases the surface electron density. The enhanced electron availability on silver possibly facilitates multi-electron transfers. The formation of methanol from CO2 requires more electrons (6 e–) than formic acid (2 e−) per molecule of product formed, which likely accounts for the preferential formation of methanol over formic acid upon silver loading.

The extraction of negative ions request conditions such as electrons are magnetized, so that a collisionless model is clearly overoptimistic, and collisions must be included to model electron co-extraction (an undesired effect). Collision dependence from speed is fully treated in this paper, addressing also the difficult case of Coulomb collisions. The kinetic effects are important in the sheath and presheath region, giving integral equations for electron density, current and collision variation along extraction axis z. With a careful description of the closed orbit variables and of the recirculation effect, integral kernels are reduced to expression suitable for computation. Numerical results for the plasma conductivity and average emission angle in Coulomb collision dominated regime are given and compared with similar results of constant collision frequency models.The extraction of negative ions request conditions such as electrons are magnetized, so that a collisionless model is clearly overoptimistic, and collisions must be included to model electron co-extraction (an undesired effect). Collision dependence from speed is fully treated in this paper, addressing also the difficult case of Coulomb collisions. The kinetic effects are important in the sheath and presheath region, giving integral equations for electron density, current and collision variation along extraction axis z. With a careful description of the closed orbit variables and of the recirculation effect, integral kernels are reduced to expression suitable for computation. Numerical results for the plasma conductivity and average emission angle in Coulomb collision dominated regime are given and compared with similar results of constant collision frequency models.

Multi cusp DC arc-discharge hydrogen negative ion (H−) source has been developed for the proton cyclotron applications. The purpose of this study is to understand the dependence of the H− production on the operation parameters and optimize the H− production in the source. In this paper, we focus on the effect of magnetic filter field on the H− volume production. The H− volume production in the source has been numerically calculated in the two case of magnetic filter field by using 3D electron transport code and 0D rate equations. The result has suggest that the effect of magnetic filter field on H− beam current could be explained by the enhanced electron density in the extraction region.Multi cusp DC arc-discharge hydrogen negative ion (H−) source has been developed for the proton cyclotron applications. The purpose of this study is to understand the dependence of the H− production on the operation parameters and optimize the H− production in the source. In this paper, we focus on the effect of magnetic filter field on the H− volume production. The H− volume production in the source has been numerically calculated in the two case of magnetic filter field by using 3D electron transport code and 0D rate equations. The result has suggest that the effect of magnetic filter field on H− beam current could be explained by the enhanced electron density in the extraction region.

The dynamics of plasma-surface interaction, often utilized for various material processing and nanoparticle synthesis, depends on electron energy distribution function (EEDF) of plasma. While most of the applications employ non-thermal plasmas at low pressure employing magnetic field, present work explores dynamics of plasma EEDF at atmospheric pressure (760 torr) where magnetic field is no longer required. Time evolution of EEDF during initial stage of microwave (2.45 GHz) plasma formation along a small capillary tube (8 mm diameter and 5 cm length) filled with a noble gas (Ar, He or Ne) is investigated using Monte Carlo simulation. The result shows that the plasma initially evolves with transient phase where electron density and its energy keeps on increasing with time, followed by the equilibrium phase at t ∼ 200 ns where EEDF relaxation is observed. The EEDF of Ar and Ne plasma indicates higher ionization and higher energy electrons than He plasma and hence can be relied for use in high-temperature treatment of surfaces. There are some applications where weakly ionized plasmas are proved to show better results and hence He plasmas should be preferred. Due to lower ion mobility of ions, Ar and Ne plasmas are also preferable for smaller size nanoparticle formation.The dynamics of plasma-surface interaction, often utilized for various material processing and nanoparticle synthesis, depends on electron energy distribution function (EEDF) of plasma. While most of the applications employ non-thermal plasmas at low pressure employing magnetic field, present work explores dynamics of plasma EEDF at atmospheric pressure (760 torr) where magnetic field is no longer required. Time evolution of EEDF during initial stage of microwave (2.45 GHz) plasma formation along a small capillary tube (8 mm diameter and 5 cm length) filled with a noble gas (Ar, He or Ne) is investigated using Monte Carlo simulation. The result shows that the plasma initially evolves with transient phase where electron density and its energy keeps on increasing with time, followed by the equilibrium phase at t ∼ 200 ns where EEDF relaxation is observed. The EEDF of Ar and Ne plasma indicates higher ionization and higher energy electrons than He plasma and hence can be relied for use in high-temperature tr...

The steady improvement of the analysis of atomic and molecular hydrogen emissivities together with the possibility to apply a high-resolution spectrometer motivated repeating at BATMAN Upgrade the detailed optical emission spectroscopy investigations performed at the BATMAN test facility in 2006. Although the test facility as a whole was upgraded, the RF-driven prototype source for the ITER NBI systems basically remained the same. The measurements were carried out in the first operation phase of BATMAN Upgrade i.e. in hydrogen in the volume operation mode of the negative ion source. The previously measured gas temperature of 1000 K in the driver, increasing to about 1200 K towards the grid is now determined to be 630 K in the whole source. Moreover, by evaluating now 12 rotational lines of the molecular Fulcher-α radiation instead of five, the presence of a two-temperature rotational distribution is demonstrated, revealing a hot ensemble with a temperature of about 4300 K. For the line of sight through the driver and the one parallel to the grid, the evaluation of the electron density and temperature showed similar values and trends as in the campaign of 2006. The third line of sight observes the expansion region and gives access, for the first time, to the plasma parameters in this region. Dependencies on the variation of the magnetic filter field strength and its topology are observed. The density ratio of atomic to molecular hydrogen is about 0.3 in all source regions, revealing no pronounced dependence on the filter field; however, due to the complex analysis procedure, the uncertainties are quite high for this parameter.

TheFull-potential linearized augmented plane wave method in WIEN2k was used to calculate electronic and magnetic properties of Fe2NiMn and Electronic properties of Fe2NiCo. The lattice constant were calculated to be 5.8 A for Fe2NiMn as well as for Fe2NiCo. The electron density calculated is not completely spherical which indicates the presence of half-metallic nature of the alloy in majority and minority spin of Fe2NiMn and Fe2NiCo. The magnetic moment were also analyzed.

The capacitive coupled radio frequency (CCRF) discharges have been used extensively in laboratory studies and industry. In this research, the neon-oxygen and neon-hydrogen mixture discharges have been generated using radiofrequency power source in the discharge chamber for different pressures. The effects of oxygen and hydrogen mixed to the neon gas discharge on electron temperature and electron density variation have been investigated with a single Langmuir probe with cylindrical geometrical design. The Debye length and electron energy distribution function (EEDF) of these discharges can be also recorded from Langmuir Probe. Apart from these, the spectra of these discharges have been recorded by optical emission spectroscopy (OES). By examining the obtained spectral lines, it has been tried to determine the parameters which cause the change of the spectral lines. In summary, the aim of this study is to investigate some similarities and/or differences between neon-hydrogen and neon-oxygen mixture discharges.

Total electronic cross-section, total atomic cross-section, effective atomic number, and effective electron density were determined experimentally and theoretically for Sm2O3, SmI2, and SmCl3 compounds. The mass attenuation coefficient and total atomic cross section were calculated experimental values for Sm2O3, SmI2, and SmCl3 compounds. Theoretical mass attenuation coefficient values were computed from the XCOM data program. Exciting Sm comp ounds were measured using a Si(Li) detector with γ photons at 59.543 keV from 241 Am annular source. We have performed the measurements for the calculations of these values in attenuation and direct excitation experimental geometry. The effective atomic number and electron density for Sm compounds are being reported here for the first time.

ELECTRON BEAM EXTRACTION ON PLASMA CATHODE ELECTRON SOURCES SYSTEM. The electron beam extraction through window of Plasma Generator Chamber (PGC) for Pulsed Electron Irradiator (PEI) device and simulation of plasma potential has been studied. Plasma electron beam is extracted to acceleration region for enlarging their power by the external accelerating high voltage (Vext) and then it is passed foil window of the PEI for being irradiated to any target (atmospheric pressure). Electron beam extraction from plasma surface must be able to overcome potential barrier at the extraction window region which is shown by estimate simulation (Opera program) based on data of plasma surface potential of 150 V with Ueks values are varied by 150 kV, 175 kV and 200 kV respectively. PGC is made of 304 stainless steel with cylindrical shape in 30 cm of diameter, 90 cm length, electrons extraction window as many as 975 holes on the area of (15 × 65) cm2 with extraction hole cell in 0.3 mm of radius each other, an cylindrical shape IEP chamber is made of 304 stainless steel in 70 cm diameter and 30 cm length. The research result shown that the acquisition of electron beam extraction current depends on plasma parameters (electron density ne, temperature Te), accelerating high voltage Vext, the value of discharge parameter G, anode area Sa, electron extraction window area Se and extraction efficiency value α.

Two strongly related theorems on non-degenerate ground state electron densities serve as the basis of “Molecular Informatics”. The Hohenberg-Kohn theorem is a statement on global molecular information, ensuring that the complete electron density contains the complete molecular information. However, the Holographic Electron Density Theorem states more: the local information present in each and every positive volume density fragment is already complete: the information in the fragment is equivalent to the complete molecular information. In other words, the complete molecular information provided by the Hohenberg-Kohn Theorem is already provided, in full, by any positive volume, otherwise arbitrarily small electron density fragment. In this contribution some of the consequences of the Holographic Electron Density Theorem are discussed within the framework of the “Nuclear Charge Space” and the Universal Molecule Model. In the Nuclear Charge Space” the nuclear charges are regarded as continuous variables, and ...

Hydrogen atomic emission lines and molecular Fulcher-α bands were observed at the vicinity of metal surfaces bombarded with a magnetized hydrogen plasma. The target bias dependence as well as spatial dependence of emission intensities were obtained. The spatial distribution of Fulcher-α spectral intensities taken by varying the distance from the bombarded tantalum surface suggests that hydrogen molecules concentrate in region near the surface. Obtained Fulcher-α intensity and Hα/Hβ intensity ratio are higher for tantalum wall compared to tungsten wall. On the other hand, lower Hβ/Hγ intensity ratio was obtained for tantalum wall. The measured results are discussed in terms of tantalum wall effectiveness in increasing the local H- density and decreasing the electron density. The target bias dependences of atomic and molecular species indicate that the balance of particles incident onto the surface is a key factor determining the production rate of vibrationally excited molecules.

Thin Films of PEDOT: PSS on the Indium Tin Oxide substrate were prepared at different spinning speed, for instance, 1000 rpm, 1500 rpm, 2000 rpm & 4000 rpm by spin-coating technique. The out-of-plane structure of the thin films was determined by x-ray reflectivity technique to produce electron density profiles, thickness and roughness. High spinning speed (2000 and above) causes segregation of PSS at the top. The overall reduction in electron density of the films indicates that the high electron density component of the film is removed from top along the fluid due to strong centrifugal force at the top. The results bring interesting insight into the structure of PEDOT: PSS films which is likely to influence its current transport properties.

We review studies of two kinds of dips in spectral line profiles emitted by plasmas – the dips that have been predicted theoretically and observed experimentally: Langmuir-wave-caused dips (L-dips) and charge-exchange-caused dips (X-dips). There is a principal difference with respect to positions of L-dips and X-dips relative to the unperturbed wavelength of a spectral line: positions of L-dips scale with the electron density Ne roughly as Ne1/2, while positions of X-dips are almost independent of Ne (the dependence is much weaker than for L-dips). L-dips and X-dips phenomena are important both fundamentally and practically. The fundamental importance is due to a rich physics behind each of these phenomena. As for important practical applications, they are as follows. Observations of L-dips constitute a very accurate method to measure the electron density in plasmas – the method that does not require the knowledge of the electron temperature. L-dips also allow measuring the amplitude of the electric field...

Recently, researchers produced perovskites structures used in optoelectronic devices as substrates, sensors. CsPbBr3 crystal is found in the cubic perovskite structure and its space group is Pm-3m. CsPbBr3 is a developing material for detection of X- and γ-ray radiations and the knowledge of the attenuation parameters of CsPbBr3 crystal is important. In this study, some photon shielding parameters such as mass attenuation coefficient (μρ), effective atomic number (Zeff) and electron density (Nel) have been investigated for CsPbBr3 compound. The theoretical values of μρ have been calculated in the energy range from 1 keV to 100 GeV using WinXCom computer code and these values have been used in order to calculate the values of Zeff and Nel in the same energy range.Recently, researchers produced perovskites structures used in optoelectronic devices as substrates, sensors. CsPbBr3 crystal is found in the cubic perovskite structure and its space group is Pm-3m. CsPbBr3 is a developing material for detection of X- and γ-ray radiations and the knowledge of the attenuation parameters of CsPbBr3 crystal is important. In this study, some photon shielding parameters such as mass attenuation coefficient (μρ), effective atomic number (Zeff) and electron density (Nel) have been investigated for CsPbBr3 compound. The theoretical values of μρ have been calculated in the energy range from 1 keV to 100 GeV using WinXCom computer code and these values have been used in order to calculate the values of Zeff and Nel in the same energy range.

In most ray tracing simulation codes of the extraction region of a negative ion source, the particle initial velocity must be assigned by some simplified empirical models, in complete analogy with a positive ion source, which makes efficient two-dimensional (2D) and 3D three-dimensional simulations possible. Since electron emission from adequately magnetized plasma is due to collisions, not included in the pure ray-tracing codes, more complete physical models of the presheath plasma are discussed to get insight of electron velocity entering the sheath and the beam region. Full kinetic 1D2V (one space dimension, two velocity components) models are here presented. A reduced one-dimensional (1D) integrodifferential model of a simplified kinetic equation (in two velocity components) including magnetic field and effective collisions, recently analytically described, is extended to the case of constant collision frequency; in z, pz phase space, closed orbits enhance electron density, as calculated. Introducing the escape integral limit, the expected trends of electron emission velocity and angle are given.In most ray tracing simulation codes of the extraction region of a negative ion source, the particle initial velocity must be assigned by some simplified empirical models, in complete analogy with a positive ion source, which makes efficient two-dimensional (2D) and 3D three-dimensional simulations possible. Since electron emission from adequately magnetized plasma is due to collisions, not included in the pure ray-tracing codes, more complete physical models of the presheath plasma are discussed to get insight of electron velocity entering the sheath and the beam region. Full kinetic 1D2V (one space dimension, two velocity components) models are here presented. A reduced one-dimensional (1D) integrodifferential model of a simplified kinetic equation (in two velocity components) including magnetic field and effective collisions, recently analytically described, is extended to the case of constant collision frequency; in z, pz phase space, closed orbits enhance electron density, as calculated. Introducing ...

We performed laboratory measurements to observe extreme ultraviolet (EUV) spectra of highly charged Fe ions using a compact electron beam ion trap. A high resolution flat-field grazing incidence spectrometer was employed to record spectra in the wavelength range of 160-230 A. The intensity ratios were obtained as a function of electron density, which was experimentally determined from the spatial distribution of the ion cloud and the size of the electron beam. The results are compared with the SERTS 95 active region data and present model calculations. Our measured data points show rather good agreement with the observational data of SERTS 95 and calculated intensity ratios.

Layered structure molybdenum dichalcogenides, MoX2 (X = S, Se, and Te) are in focus as reversible charge storage electrode for pseudocapacitor applications. Correlation between number of layer and bandgap of the materials has been established by previous researchers. The correlation would reveal a connection between the bandgap and charge storage properties i.e., amount of charges that could be stored, and speed of storage or dissociation. In this work, fundamental parameters viz., (i) size-offset between a monolayer and exciton Bohr radius of MoX2 and (ii) ground and excited state electron density have been studied. We have identified realistic monolayer models of MoX2 using quantum chemical calculations which explain a correlation between size-offset and charge storage properties. We conclude that as the size-offset decreases, the higher possibility of wave functions overlap between the excited state, and ground state electrons; therefore the higher the electron mobility, and conductivity of the MoX2 would be.

In this paper, we explore the effect of temperature and electron density on the plasmon dispersion of a semiconductor electron quantum wire using the random phase approximation. The transverse motion of the wire electrons is assumed to be confined by a symmetric harmonic potential. Numerical results are reported for the dispersion of plasmons over a wide range of temperature and electron density. The plasmon frequency is found to have a blue shift with increase in temperature and/or the electron density parameter rs.In this paper, we explore the effect of temperature and electron density on the plasmon dispersion of a semiconductor electron quantum wire using the random phase approximation. The transverse motion of the wire electrons is assumed to be confined by a symmetric harmonic potential. Numerical results are reported for the dispersion of plasmons over a wide range of temperature and electron density. The plasmon frequency is found to have a blue shift with increase in temperature and/or the electron density parameter rs.

The epitaxial growth of quantum wells composed of high quality allows the production and application to their device of new structures in low dimensions. The potential profile at the junction is determined by free carriers and by the level of doping. Therefore, the shape of potential is obtained by the electron density. Energy level determines the number of electrons that can be occupied at every level. Energy levels and electron density values of each level must be calculated self consistently. Starting with V(z) test potential, wave functions and electron densities for each energy levels can be calculated to solve Schrodinger equation. If Poisson’s equation is solved with the calculated electron density, the electrostatic potential can be obtained. The new V(z) potential can be calculated with using electrostatic potential found beforehand. Thus, the obtained values are calculated self consistently to a certain error criterion. In this study, the energy levels formed in the interfacial potential, electron density in each level and the wave function dependence of material parameters were investigated self consistently.

We have investigated the structural and electronic properties of carbon nanotube with small fullerene halves Cn (n ≤ 40) which are covalently bonded to the side wall of an armchair single wall carbon nanotube (SWCNT) using first principle method based on density functional theory. The fullerene size results in weak bonding between fullerene halves and carbon nanotube (CNT). Further, it was found that the C-C bond distance that attaches the fullerene half and CNT is of the order of 1.60 A. The calculated binding energies indicate the stability of the complexes formed. The HOMO-LUMO gaps and electron density of state plots points towards the metallicity of the complex formed. Our calculations on charge transfer reveal that very small amount of charge is transferred from CNT to fullerene halves.

Monte Carlo (MC) dose calculations in radiotherapy typically use Computed Tomography (CT) images of the patient since they can provide electron density (ρe) and effective atomic number (Zeff) information of tissues. An accurate calculation of absorbed dose and appropriate correction for inhomogeneities is partially determined by the Hounsfield Units (HU) dependence on these parameters. In this work HU calibration results are presented in terms of Zeff and ρe by using tissue-equivalent materials and a dual-energy CT method. We compared calculated values of Zeff and ρe with the ones provided by the manufacturer. Mean percentage differences (MPD) of 3.2% were observed for Zeff, while for ρe the average difference was 4.1%. When beam hardening correction was applied, the MPD on Zeff and ρe extraction were 2.4% and 3.2%, respectively.

Spatial characterization of plasma detachment attributed to molecular activated recombination (MAR) has been done by measuring distributions of electron temperature, electron density, space potential and floating potential of divertor simulation plasma in GAMMA 10/PDX tandem mirror with Langmuir probes. As the hydrogen pressure in the divertor simulation experimental module was increased by supplying additional hydrogen gas, the electron temperature near the target decreased from 30 eV to about 2 eV and the electron density first increased to an order of nearly 1017 m−3, and then decreased in contrast to the density measured at the upstream of the target which became saturated. The density decrement was higher near the corner of the V-shaped target although temperature distribution was almost flat near the target. In addition, space potential decreased, floating potential increased, and then the potential difference between those became small. The potential difference decreased to almost zero near the tar...

Energy bands, density of states (DOS), Mulliken population (MP) and electron momentum densities (EMDs) of CdWO4 are presented using hybrid exchange and correlation functionals namely B3LYP, B3PW and PBE0. To validate the present hybrid potentials, theoretical EMDs have been compared with the experimental Compton profile. It is found that LCAO-B3LYP based Compton profile gives a better agreement with experiment than other theoretical profiles. The energy bands and DOS show a wide band gap semiconducting nature of CdWO4. The theoretical band gap obtained using B3LYP scheme reconciles well with the available experimental data. In addition, we have also presented the anisotropies in EMDs along [100], [110] and [001] directions and the bonding effects using the MP data.

We present a statistical survey of the energy spectrum of solar wind suprathermal (∼0.1-1.5 keV) electrons measured by the WIND 3-D Plasma & Energetic Particle (3DP) instrument at 1 AU during quiet times at the minimum and maximum of solar cycles 23 and 24. Firstly, we separate strahl (beaming) electrons and halo (isotropic) electrons based on their features in pitch angle distributions. Secondly, we fit the observed energy spectrum of both the strahl and halo electrons at ∼0.1-1.5 keV to a Kappa distribution function with an index κ, effective temperature Teff and density n0. We also integrate the the measurements over ∼0.1-1.5 keV to obtain the average electron energy Eavg of the strahl and halo. We find a strong positive correlation between κ and Teff for both the strahl and halo, possibly reflecting the nature of the generation of these suprathermal electrons. Among the 245 selected samples, ∼68% have the halo κ smaller than the strahl κ, while ∼50% have the halo Eh larger than the strahl Es.

An ion sensitive probe (ISP) has been installed in the divertor simulation module of the largest tandem mirror plasma device GAMMA 10/PDX in order to evaluate the property of the high temperature end loss plasmas. The ISP has the capability to evaluate ion temperature (Ti), electron temperature (Te), electron density and plasma space potential, simultaneously. We have tested the ISP measurement for several discharge and neutral gas pressure conditions. Tievaluated by using an ion collector of the ISP shows ∼6 eV which corresponds to the perpendicular component of Ti in principle. Te evaluated by the current-voltage characteristics of an electron guard electrode of the ISP shows ∼4 eV which is lower than Te obtained by Langmuir probes upstream and downstream of the ISP. These results indicate the existence of anisotropic ion and electron temperatures in the D-module.

In the paper, last experiment’s results on sub-THz wave emission from the area of relativistic electron beam-plasma interaction in the GOL-PET device are described. A plasma column with the diameter of 6 cm, length of 2.5 m and electron density (0.2-2)×1015 cm−3 is confined by multiple-mirror magnetic field with mean value of 4 T. The relativistic electron beam injected into the column, has the following parameters: energy Eb ∼ 0.8 MeV, current Ib ∼ 30 kA, current density Jb ∼ 2 kA/cm2 in the mean magnetic field. Previous studies have shown that the beam pumps the plasma electron oscillations in a vicinity of the upper hybrid wave branch. These plasma oscillations can be converted in electromagnetic waves on regular or artificial plasma density gradients in a vicinity of upper hybrid frequency. The electromagnetic waves with the double upper hybrid frequency are also generated in the beam-plasma system due to coalescence of the plasma oscillations in case of high level of the oscillation energy density. T...

The effect of neutral Ar injection on the plasma parameters is investigated numerically by using a multi-fluid code in this research. Reduction of electron and ion temperature has been observed according to the increment in injected neutral Ar density. The heat flux on the target plate has been also reduced with the increasing of injected neutral Ar density. For Ar: 2.0 × 1018 m−3 injection, electron temperature on the target plate reduced to about 1.5 eV. Increase in electron and ion density has been observed at lower injected Ar density. However, at higher Ar injection, electron density and ion density goes to be saturated. These outcomes indicate that the plasma in the end region approaches towards the plasma detachment state.

In GAMMA 10/PDX, a temperature-controlled V-shaped target has been utilized to study an effect of target temperature on hydrogen recycling. The V-shaped tungsten target in the divertor simulation experimental module (D-module) is heated up to 573 K and it is exposed to the end loss plasma. It is found that the Hα intensity and the electron density of the plasma in front of the target are positively correlated with the target temperature, indicating that the recycling is enhanced due to increase in the target temperature. Moreover, additional hydrogen gas is injected into the D-module with the temperature-controlled target. As the amount of hydrogen gas injection increased, enhancement of hydrogen recycling by high temperature target becomes smaller.

Performance of flash radiography units implies a high spatial resolution. Thus, focused electron beams are utilized to produce bremsstrahlung x-ray at the solid target. Strong heating of the target up to 1-10 eV temperature and formation of dense plasma can lead to beam disruption. In case of multi-pulse operation mode of radiography unit the plasma produced by the first pulse can strongly affect subsequent pulses. In present work we utilize the model of Zeldovich and Raizer to estimate the electron density in the target plasma. The typical parameters of radiography units based on linear induction accelerators is considered. It is shown that electron density in plasma expanding after first pulse is high enough to affect subsequent electron beams.

Structural property of polycrystalline La2-xErxMo2O9 has been investigated. Rietveld refinements at room temperature of the materials suggest a single phase nature with cubic symmetry (space group P213). The electron density contour plot confirms the nature of different cation-oxygen bonds. Time dependent mean square displacement (√ ) and the spatial extent of the sub-diffusive motion (√ ) are evaluated using the linear response theory. The localized hop at O2 and O3 sites is found to be favorable for oxygen ion migration for these systems.

Future high energy accelerators require polarized electron sources that can generate high bunch charge and/or high density electron beam with low emittance. Various superlattice photocathodes and a high voltage load-lock DC gun have been developed at Nagoya University for this purpose. Using a GaAs-GaAsP strained superlattice photocathode, the bunch charge of 8nC was extracted in a 1.6ns bunch with a 20 mm diameter, and that of 3.3pC in ∼30ps bunch with 1.2mm diameter.

Characteristics of ionic plasmas, observed in a high-density hydrogen negative ion source, are investigated with a multi-diagnostics system. The ionic plasma, which consists of hydrogen positive- and negative-ions with a significantly low-density of electrons, is generated in the ion extraction region, from which the negative ions are extracted through the plasma grid. The negative ion density, i.e., the ionic plasma density, as high as the order of 1×1017m−3, is measured with cavity ring-down spectroscopy, while the electron density is lower than 1×1016m−3, which is confirmed with millimeter-wave interferometer. Reduction of the negative ion density is observed at the negative ion extraction, and at that time the electron flow into the ionic plasma region is observed to conserve the charge neutrality. Distribution of the plasma potential is measured in the extraction region in the direction normal to the plasma grid surface with a Langmuir probe, and the results suggest that the sheath is formed at the plasma boundary to the plasma grid to which the bias voltage is applied. The beam extraction should drive the negative ion transport in the ionic plasma across the sheath formed on the extraction surface. Larger reduction of the negative ions at the beam extraction is observed in a region above the extraction aperture on the plasma grid, which is confirmed with 2D image measurement of the Hα emission and cavity ring-down spectroscopy. The electron distribution is also measured near the plasma grid surface. These various properties observed in the ionic plasma are discussed.

New concepts on the irreversible crystal deformation as a structure transformation caused by a change in interatomic interactions at fluctuations of the electron density under loading are described. The change in interatomic interactions lead to the excitation of dynamical displacements of atoms. A model and a theory of a deformable pristine crystal taking into account the excitation of thermally activated and dynamical displacements of atoms are suggested. New mechanisms of the nucleation of plastic deformation carriers and destruction in pristine crystals at the real value of the deforming stress are studied.

Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (T{sub e}) and electron number density (n{sub e}) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10{sup −17} − 10{sup −18} m{sup −3} where the electron temperature is between 1.00−2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

Geometry optimization of [Li(DMSO)n]+ and [Al(DMSO)n]3+ complexes with n = 1 - 6 in DMSO (dimethyl sulfoxide, (CH3)2SO) solutions is performed using DFT treatment with B3LYP hybrid functional and cc-pVDZ basis sets. Solvent effects are approximated within Integral Equation Formalism Polarisable Continuum Model. Electron structure of individual model systems is investigated in terms of Quantum Theory of Atoms-in-Molecule topological analysis of electron density. Metal-DMSO bonding through oxygen atom is preferred. The most probable coordination numbers n = 4 for Li+ and n = 6 for Al3+ complexes with DMSO are concluded.

As the negative hydrogen ion density nH− is a key parameter for the investigation of negative ion sources, its diagnostic quantification is essential in source development and operation as well as for fundamental research. By utilizing the photodetachment process of negative ions, generally two different diagnostic methods can be applied: via laser photodetachment, the density of negative ions is measured locally, but only relatively to the electron density. To obtain absolute densities, the electron density has to be measured additionally, which induces further uncertainties. Via cavity ring-down spectroscopy (CRDS), the absolute density of H− is measured directly, however LOS-averaged over the plasma length. At the ECR-discharge HOMER, where H− is produced in the plasma volume, laser photodetachment is applied as the standard method to measure nH−. The additional application of CRDS provides the possibility to directly obtain absolute values of nH−, thereby successfully bench-marking the laser photodeta...