Detection of Group of Super Fast Electrons in Hydrogen Plasma From the Ratio of the Intensity of H[sub 2] Fulcher α(d[sup 3]Π[sub u]−a[sup 3]Σ[sub g]) and H[sub α] Spectral Lines

2010 ◽  
Author(s):  
S. R. Mijovic ◽  
M. J. Vuceljic ◽  
Angelos Angelopoulos ◽  
Takis Fildisis
Keyword(s):  
Hydrogen Plasma ◽  
Spectral Lines ◽  
Fast Electrons

scholarly journals Fringe structures and tunable bandgap width of 2D boron nitride nanosheets

2014 ◽  
Vol 5 ◽  
pp. 1186-1192 ◽  
Author(s):  
Peter Feng ◽  
Muhammad Sajjad ◽  
Eric Yiming Li ◽  
Hongxin Zhang ◽  
Jin Chu ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hydrogen Plasma ◽  
Hydrogen Gas ◽  
Spectral Lines ◽  
Bandgap Width ◽  
Raman Scattering Spectroscopy ◽  
Boron Nitride Nanosheets ◽  
Tunable Bandgap ◽  
Curved Structures ◽  
Digitally Controlled

We report studies of the surface fringe structures and tunable bandgap width of atomic-thin boron nitride nanosheets (BNNSs). BNNSs are synthesized by using digitally controlled pulse deposition techniques. The nanoscale morphologies of BNNSs are characterized by using scanning electron microscope (SEM), and transmission electron microscopy (TEM). In general, the BNNSs appear microscopically flat in the case of low temperature synthesis, whereas at high temperature conditions, it yields various curved structures. Experimental data reveal the evolutions of fringe structures. Functionalization of the BNNSs is completed with hydrogen plasma beam source in order to efficiently control bandgap width. The characterizations are based on Raman scattering spectroscopy, X-ray diffraction (XRD), and FTIR transmittance spectra. Red shifts of spectral lines are clearly visible after the functionalization, indicating the bandgap width of the BNNSs has been changed. However, simple treatments with hydrogen gas do not affect the bandgap width of the BNNSs.

Temperature Determination in an Inductively Coupled rf Plasma

1976 ◽  
Vol 30 (1) ◽  
pp. 34-38 ◽  
Author(s):  
K. Visser ◽  
F. M. Hamm ◽  
P. B. Zeeman
Keyword(s):  
Atmospheric Pressure ◽  
Thermal Equilibrium ◽  
Hydrogen Plasma ◽  
Spectral Lines ◽  
Rf Plasma ◽  
Temperature Profiles ◽  
Inductively Coupled ◽  
Temperature Method ◽  
The Difference ◽  
Line Temperature

Simultaneous relative radiances of the Hβ, Hγ, and Hδ spectral lines of hydrogen were measured sequentially at various lateral positions in an inductively coupled rf argon-hydrogen plasma operated at atmospheric pressure (12 kW, 9 MHz). Measurements to take self-absorption into account were also performed. By applying an Abel integral inversion, a radial radiance profile for each line was obtained. With the two-line temperature method, simultaneous temperature profiles were obtained from each of the three line-pairs. The difference between these three sets of values and the negative values obtained for the Hγ, Hδ pair indicates that thermal equilibrium does not exist in this plasma.

Intensities of Hβ and Hγ in Hydrogen Plasma Spectrum with High RF Power Levels at ICP

2013 ◽  
Vol 774-776 ◽  
pp. 471-478
Author(s):  
Song Bai Wang ◽  
Guang Jiu Lei ◽  
Ming Li ◽  
Li Ming Yu ◽  
Ying Nan Bu ◽  
...  
Keyword(s):  
Stark Effect ◽  
Hydrogen Plasma ◽  
Input Power ◽  
Ion Source ◽  
Spectral Lines ◽  
Rf Plasma ◽  
Rf Power ◽  
Balmer Series ◽  
Rf Ion Source ◽  
Plasma Spectrum

In high-power RF ion source, three different regions of the Hβand Hγintensities in the Balmer series of spectral lines for atomic hydrogen plasma were investigated. Three different regions of the Hβand Hγintensities were detected by the increase of input power (0-6 kW) at ICP. In hydrogen plasma spectrum, the Hβand Hγintensities showed three processes: slowly increase, quickly increase and stable saturation. The Stark effect in strong electrical field plays a crucial role in dominating the Balmer Hβand Hγemissions from high-density RF plasma.

scholarly journals The scattering of fast electrons by atomic nuclei

1929 ◽  
Vol 124 (794) ◽  
pp. 425-442 ◽  
Keyword(s):  
Electromagnetic Field ◽  
Wave Equation ◽  
Magnetic Moment ◽  
Spectral Lines ◽  
Transformation Theory ◽  
General Transformation ◽  
Atomic Spectra ◽  
Fast Electrons ◽  
Principle Of Relativity ◽  
Atomic Nuclei

Section 1 .— The hypothesis that the electron has a magnetic moment was, as is well known, first introduced to account for the duplexity phenomena of atomic spectra. More recently, however, Dirac has succeeded in accounting for these same phenomena by the introduction of a modified wave equation, which conforms both to the principle of relativity and to the general transformation theory. Formally, at least, on the new theory also, the electron has a magnetic moment of εh/mc , but when the electron is in an atom we cannot observe this magnetic moment directly; we can only observe the foment of the whole atom, or, of course, the splitting of the spectral lines, which we may say is “caused” by this moment. The question arises, has the free electron "really” got a magnetic moment, a magnetic moment that we can by any conceivable experiment observe? The question is not so simple as it might seem, because a magnetic moment εh/mc can never be observed directly, e.g ., with a magnetometer; there is always an uncertainty in the eternal electromagnetic field, due to the uncertainty in the position and velocity of the electron, and this uncertainty is greater than the effect of the electron magnet which we are trying to observe.

scholarly journals Investigation and diagnostics of plasma flows in a pulsed plasma accelerator for experimental modelling of processes in tokamaks

2021 ◽  
Vol 5 (4) ◽  
pp. 198-210
Author(s):  
M. K. Dosbolayev ◽  
A. B. Tazhen ◽  
T. S. Ramazanov
Keyword(s):  
Vacuum Chamber ◽  
Arc Discharge ◽  
Hydrogen Plasma ◽  
Beam Current ◽  
Plasma Accelerator ◽  
Spectral Lines ◽  
Pulsed Plasma ◽  
Stark Broadening ◽  
Balmer Series ◽  
Faraday Cup

This paper presents the experimental results on electron, ion temperatures and densities in a pulsed plasma accelerator. The values of electron densities and temperatures were computed using the methods of relative intensities of Hα and Hβ lines, Hβ Stark broadening, and the technique is based on Faraday cup beam current measurements. In this work, a linear optical spectrometer S-100 was used to acquire the emission spectra of hydrogen and air plasmas. In this spectrum, there are some lines due to Fe, Cu, N2, O2, and H2. The series of visible lines in the hydrogen atom spectrum are named the Balmer series. The spectral emissions of iron and copper occur throughout the gas breakdown and ignition of an arc discharge, during the erosion and sputtering of materials. The vacuum chamber and coaxial electrodes were made. The electron temperatures and densities in a pulsed plasma accelerator, measured via relative intensities of spectral lines and Stark broadening, at a charging voltage of a capacitor bank of 3 kV and a working gas pressure in a vacuum chamber of 40 mTorr, were 2.6 eV and 1.66 · 1016 cm−3 for hydrogen plasma. These results were compared with the Faraday cup beam current measurements. However, no match was found. Considering and analyzing this distinction, we concluded that the spectral method of plasma diagnostics provides more accurate results than electrical measurement. The theory of probe measurements can give approximate results in a moving plasma.

scholarly journals Особенности возбуждения линий главной серии атомов подгруппы цинка электронным ударом. I. Кадмий

2020 ◽  
Vol 128 (2) ◽  
pp. 176
Author(s):  
Г.Г. Богачев ◽  
Е.Ю. Ремета
Keyword(s):  
Principal Series ◽  
Direct Calculation ◽  
Energy Shift ◽  
Spectral Lines ◽  
Scattered Electron ◽  
Excitation Functions ◽  
Fast Electrons ◽  
Crossed Beams ◽  
Slow Electrons ◽  
Autoionizing States

Using the technique of crossed beams of slow electrons and cadmium atoms, the excitation functions of three spectral lines of its principal series (166.9, 152.7, 146.9 nm) outgoing from the 5snp 1Po1 levels were measured (n = 6, 7, 8, respectively). In the range of electron energies 12–18 eV, a manifestation of the post-collision interaction of slow scattered electrons and fast electrons ejected during the decay of autoionizing states was found in these functions. This process, at incident electron energies of 11.8, 12.4, and 16.6 eV, leads to additional population of the initial levels of spectral transitions and, correspondingly, to maxima on the excitation functions due to the capture of a scattered electron to these excited levels. The terms of autoionizing states of the atom responsible for the observed maxima on the excitation functions of spectral lines are established. In the classical approximation, by two methods – direct calculation and least squares approximation – estimate the effective widths of the electronic decay of autoionizing states, the combined action of which leads to an energy shift of the maxima. Approximate calculation formulas are used, which are valid for various relations between the post-collision shift of the maxima on the excitation functions and the binding energy of atomic levels.

The Interpretation of Line Profiles

1977 ◽  
Vol 36 ◽  
pp. 191-215
Author(s):  
G.B. Rybicki
Keyword(s):  
Magnetic Fields ◽  
Atomic Physics ◽  
Velocity Fields ◽  
Spectral Lines ◽  
Inhomogeneous Structure ◽  
The Sun ◽  
Line Profiles ◽  
Physical Phenomena

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.

Design of Sensitive Photographic Materials for the High-Voltage Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 156-157
Author(s):  
Murray Vernon King ◽  
Donald F. Parsons
Keyword(s):  
Electron Microscope ◽  
Radiation Damage ◽  
High Voltage ◽  
Radiation Sensitivity ◽  
Fast Electrons ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Biological Studies ◽  
Low Sensitivity

Effective application of the high-voltage electron microscope to a wide variety of biological studies has been restricted by the radiation sensitivity of biological systems. The problem of radiation damage has been recognized as a serious factor influencing the amount of information attainable from biological specimens in electron microscopy at conventional voltages around 100 kV. The problem proves to be even more severe at higher voltages around 1 MV. In this range, the problem is the relatively low sensitivity of the existing recording media, which entails inordinately long exposures that give rise to severe radiation damage. This low sensitivity arises from the small linear energy transfer for fast electrons. Few developable grains are created in the emulsion per electron, while most of the energy of the electrons is wasted in the film base.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

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