MICROSAMPLE INTRODUCTION BY TUNGSTEN FILAMENT ELECTRODE INTO CAPACITIVELY COUPLED MICROWAVE PLASMA FOR ATOMIC EMISSION-SPECTROSCOPY - DIAGNOSTICS

A microwave plasma based on a capacitively coupled microwave plasma was developed and several diagnostical parameters were evaluated. This plasma was sustained at powers as low as 25 W with He as the plasma gas. Rotational (2500 K) and excitation (4500 K) temperatures were determined from N2+ and Fe, respectively. The rotational and excitation temperatures were independent of power (35-115 W), radial (- 3 to + 3 mm) and axial (1-7 mm) positions, and the He plasma gas flow-rate (4-8 l min-1). The excitation temperature decreased slightly with plasma gas flow-rate between 3 and 4 l min-1 while the rotational temperature remained constant. The electron density (4 X 10(14) cm-3) also remained unchanged with both power and radial distances.