Comparative study of an argon plasma and an argon copper plasma produced by an ICP torch at atmospheric pressure based on spectroscopic methods

Abstract

The aim of the paper is to test the accuracy of classical spectroscopic methods in the visible domain dedicated to measurements of temperature and electron density in order to conclude about the validity of thermal disequilibrium. The influence of various factors is studied: accuracy of the intensity calibration, Abel inversion of the experimental spectra, excitation temperature deduced from the relative method, absolute excitation temperature, influence of the transition probability accuracy, influence of the Biberman factor value, electron temperature from the line-to-continuum intensity ratio, electron density deduced from Stark broadening, and electron density deduced from the continuum intensity. This spectroscopic investigation is carried out for argon plasma and argon copper plasma both produced by means of an ICP torch operating at atmospheric pressure. Results are given with uncertainties for each evaluated parameter. We show that, first, the electron temperature deduced from the line-to-continuum intensity ratio has to be considered with great care; second, for argon plasma no evidence of thermal disequilibrium can be discerned, whereas for argon copper plasma a small disequilibrium of 1.2 to 1.4 at most is experimentally observed.

Electron characterization in weakly ionized collisional plasmas: from principles to techniques

“…Figure 9 represents the κ ea dominant ranges as functions of n e and the background gas pressure at different wavelengths. Similar validations of neutral bremsstrahlung-based electron diagnostics have also been conducted by several groups [159,160].…”

Thermal Plasma Decomposition of Tetrachloroethylene

“…Standard deviations of the calculated values were ± 10%. Abel inversion was not applied as it is not necessary when the plasma column has a high gradient Gaussian temperature profile as occurs in our plasma system [25].…”

Spectroscopic Diagnostics of Atmospheric Argon Microwave Plasma Based on an Inductive Coupling Window-Rectangular Resonator

“…( 2) is usually applied to calculate the electron temperature. [3,4] In the expression, 𝐼 ul is the integration of the corresponding emission coefficient 𝜀 ul over the spectral profile of the considered line (𝑢−𝑙) with the central wavelength 𝜆 ul . The continuum emission coefficient 𝜀 c results from the sum of two contributions: one is attributed to the capture of an electron by an ion, corresponding to the free-bound continuum (namely recombination continuum) with the emission coefficient 𝜀 fb ; the other one is due to the interaction between an electron and the electric field of an ion or atom, corresponding to the free-free continuum (namely bremsstrahlung) with the emission coefficient 𝜀 ff , which is the sum of 𝜀 ff,𝑧>1 associated with an ion and 𝜀 ff,𝑧=1 linked to an atom.…”