Use of nonlocal helium microplasma for gas impurities detection by the collisional electron spectroscopy method

Abstract

The collisional electron spectroscopy (CES) method, which lays the ground for a new field for analytical detection of gas impurities at high pressures, has been verified. The CES method enables the identification of gas impurities in the collisional mode of electron movement, where the advantages of nonlocal formation of the electron energy distribution function (EEDF) are fulfilled. Important features of dc negative glow microplasma and probe method for plasma diagnostics are applied. A new microplasma gas analyzer design is proposed. Admixtures of 0.2% Ar, 0.6% Kr, 0.1% N2, and 0.05% CO2 are used as examples of atomic and molecular impurities to prove the possibility for detecting and identifying their presence in high pressure He plasma (50–250 Torr). The identification of the particles under analysis is made from the measurements of the high energy part of the EEDF, where maxima appear, resulting from the characteristic electrons released in Penning reactions of He metastable atoms with impurity particles. Considerable progress in the development of a novel miniature gas analyzer for chemical sensing in gas phase environments has been made.

Particle in cell/Monte Carlo collision analysis of the problem of identification of impurities in the gas by the plasma electron spectroscopy method

“…Computed results are consistent with those obtained in the experiments. [7][8][9][10] Indeed, computed EEDF revealed sharp peaks exactly at the release energies of the electrons, emerged in the Penning reactions.…”

“…In the present work, we carried out 1d3v parallel PIC/ MCC analysis of glow discharge plasma in the mixture of helium and argon, related to the problem of identification of impurities in the gas within the PLES method. [6][7][8][9][10] Description of the PIC/MCC model is given in Section II A. The verification of the numerical code is done in Section II B.…”

Methane detection to 1 ppm using machine learning analysis of atmospheric pressure plasma optical emission spectra

“…CO 2 detection at concentrations ⩾500 ppm was achieved. However the plasma was operated below atmospheric pressure [34]. Recently, we demonstrated the feasibility of using OES to detect the presence of methane above threshold values in the low ppm range using a helium NELT plasma jet coupled with spectral analysis via machine learning techniques [35].…”

Determination of organic impurities by plasma electron spectroscopy in nonlocal plasma at intermediate and high pressures

“…Plasma electron spectroscopy (PLES) is one of the most promising novel methods [6][7][8][9][10][11][12][13][14][15][16]. The PLES method for analysis of impurities in the gas phase is based on measurements in a nonlocal gas-discharge plasma of the energy spectra of electrons in the Penning ionization reactions of atoms and molecules of an impurity A by metastable atoms of a buffer inert gas B * :…”

“…To date, detection by the PLES method has been demonstrated for impurities of various atomic and molecular inorganic substances, including inert gases (Ar, Kr), metals (Pt), molecular atmosphere (N 2 , O 2 ), as well as CO, CO 2 , CH 4 , C 2 H 4 , and NH 3 [9][10][11][12][13][14][15][16].…”