The absorbed HF power per electron in an open air helium microwave-induced-plasma flame produced by an axial injection torch

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:213009

Sola, A; Quintero, M C; Rodero, A ^[1]

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1. Univ. of Cordoba (Spain); and others

Electromagnetic devices permitting the production of microwave plasmas (M.I.P.), especially those working at atmospheric pressure, have deserved a lot of attention by scientists from their utilization as a source of excitation in atomic emission spectroscopy (A.E.S.). Among them, those so-called {open_quotes}torches{close_quotes} have been intensely studied and new designs of such devices are being continuously proposed. The interest of the microwave plasma structures lies in their ability to operate at low HF power and atmospheric pressure, as well as to support plasmas of various gases. Among them, helium seems to be of particular importance for the excitation of analytes because of its high ionization potential (24.6 eV) and, as a consequence, a high metastable energy, which determines its capability of exciting non-metals (e.g., halogens). In addition, helium offers a simpler overall background spectrum. The axial injection torch ({open_quotes}torche a injection axiale{close_quotes} or T.I.A.) designed by Moisan et al. avoids some of the problems presented by previous torches, especially the problem associated with the alteration of the discharge quartz tube normally used as a plasma container because the {open_quotes}plasma flame{close_quotes} is produced in {open_quotes}open{close_quotes} air at the tip of a metallic nozzle throughout the discharge gas flows. At the same time, T.I.A. provides a stable discharge using high HF power levels (300-900 W) and relatively low gas flow (3-13 L/min) without the necessity of additional cooling.

• OSTI ID: 213009
• Report Number(s): CONF-950749--
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AIR
EMISSION SPECTROSCOPY
HELIUM
HIGH-FREQUENCY DISCHARGES
PLASMA PRODUCTION