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M D Calzada

Publications and source records attributed to M D Calzada.

6 recordsLinked to original sources
PubMed2006

Abel inversion applied to a small set of emission data from a microwave plasma.

In this work we propose a criterion to apply the Abel inversion in the case of a small set of experimental data to be used in laboratory plasmas. The Nestor-Olsen method, spline interpolation, and Fourier transform Abel inversion have been compared in order to study the influence of statistical noise and the number of sampled data. The application of this criterion permits us to obtain a radial distribution of the plasma parameters (densities and temperatures) from the spectral line profiles emitted by the discharge. The proposed criterion has been tested using the lateral intensities of several lines emitted by a microwave helium plasma column generated at atmospheric pressure.

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PubMed2005

Spectroscopic characterization of two different microwave (2.45 GHz) induced argon plasmas at atmospheric pressure.

A surface-wave-sustained discharge created by using a surfatron device in a tube open to the atmosphere can be used to maintain a microwave (2.45 GHz) plasma at atmospheric pressure at powers of less than 300 W. The TIA (Torche a Injection Axiale) is a device also producing a plasma that, moreover, permits us to work at high power (higher than 200 W and up to 1000 W). A study of the departure from the thermodynamic equilibrium existing in the argon plasmas created by both devices has been done by using optical emission spectroscopy techniques in order to characterize them and to evaluate their possible advantages when they are used for applied purposes.

Argon↗
PubMed2005

Experimental method for determining the damping parameter of spectral lines emitted by a microwave plasma at atmospheric pressure.

In this work, a simple method for experimentally obtaining the value of the damping parameter or a-parameter of the spectral lines emitted by an argon plasma generated at atmospheric pressure is presented. The value of this coefficient indicates the proportion existing between the Lorentzian and Doppler components of the total line profile, which can be approximated to a Voigt function for our experimental conditions. The a-parameter values found were within the value interval recorded in the literature. The results obtained showed that the damping coefficient of the lines next to the fundamental level remains practically constant along the plasma column, whereas for the spectral lines involving high-lying levels, the a-parameter is sensitive to the changes in the electron density in the plasma. In this work it is also proved that the self-absorption phenomenon induces errors in the calculation of a, due to an increase in the broadening of the line profile produced by this phenomenon.

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PubMed2004

Electron density and gas temperature from line broadening in an argon surface-wave-sustained discharge at atmospheric pressure.

We have used the collisional broadening of neutral argon lines to determine the electron density and gas temperature of a microwave discharge at atmospheric pressure. The gas temperature can be obtained from the Van der Waals broadening, provided that the Stark broadening is negligible. This can be achieved by using lines from low-lying levels (close to the ground state). On the other hand, lines corresponding to transitions from high-lying levels, which are more sensitive to Stark (quadratic) broadening, can be utilized to determine electron density. The electron density values obtained from the quadratic Stark broadening of argon atoms are in reasonable agreement with those derived from the linear Stark broadening of the H(beta) line. The proposed method ensures perturbation-free access to plasma parameters, which is not the case when adding hydrogen to the discharge, even in a small amount, to observe the Balmer series lines.

Journal Article↗