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

Abstract

This study aims to improve the impurity analysis by plasma electron spectroscopy for organic molecules. Because the appearance energies of the characteristic Penning electrons vary for different chemical compounds, various impurities can be registered simultaneously in one measurement. Herein, experimental studies were conducted on helium with alcohol vapor impurities in a nonlocal negative glow plasma of a short glow micro-discharge with an increase in pressure from 15 Torr to 150 Torr. Thus, the pressure could be increased to atmospheric pressure, eliminating the need for expensive and cumbersome gas pumping systems.

Numerical simulation and experimental diagnostics of fast electron kinetics and plasma parameters in a microhollow cathode discharges in helium

“…It should be noted that in the case of probe diagnostics of plasma in complex mixtures of gases, heterogeneous reactions may occur on the surface of the probes, as well as the deposition of thin films, which make plasma diagnostics difficult [73][74][75][76]. In this regard, it is necessary to clean the probe with an electron or ion current [15,[73][74][75][76][77] before each measurement. Figure 8 shows an example of the probe characteristic of the measuring electrode and its second derivative with respect to the applied potential in a discharge in helium with an admixture of air (1000 ppm) and a discharge current of 17 mA.…”

“…Figure 8 shows an example of the probe characteristic of the measuring electrode and its second derivative with respect to the applied potential in a discharge in helium with an admixture of air (1000 ppm) and a discharge current of 17 mA. The probe CVC has a classical form with electron and ion saturation currents and a transition region between them [77][78][79]. It should be noted that the floating potential of the measuring electrode decreased from −20 V to −6 V with increasing current density from 10 to 23 mA.…”

“…Below is a comparative analysis of the results of numerical calculations and experimental values of the concentrations and temperatures of electrons. The temperature of the main group of electrons was determined from the transient part of the probe CVC, as well as from the rectilinear part of the logarithm of the first derivative of the probe current-voltage characteristic with respect to the supplied potential in accordance with the formula [77,79], and the rectilinear part of the probability function of the electron energy with respect to energy, which is proportional to the second derivative of the probe CVC [37,77].…”

A Portable Device for I–V and Arrhenius Plots to Characterize Chemoresistive Gas Sensors: Test on SnO2-Based Sensors

“…Usually, most laboratories perform on-site calibrations only by using large, bulky, and costly set-ups, which are often not suitable for performing on-field calibrations (of environmental sensors, for instance), and require trained personnel. Nowadays, much research is focused on the development of user-friendly and portable devices for gas analysis and the detection of their impurities by employing different technologies [ 29 , 30 , 31 , 32 ]. In this work, a novel, portable, and user-friendly device is introduced (so far in the form of a hand-made demonstrator), which is entirely designed, produced, and assembled at the Sensor Laboratory (SL) of the Department of Physics and Earth Sciences of the University of Ferrara and is able to characterize and/or calibrate a single MOX sensor in a laboratory and/or field, and able to analyze single or mixed gases.…”