AN IMAGING-BASED INSTRUMENT FOR FUNDAMENTAL PLASMA STUDIES

A description is given of an imaging-based instrument capable of mappi ng several fundamental properties of analytical plasmas, especially th e inductively coupled plasma. The plasma fundamental parameters includ e electron temperature and number density, heavy-particle gas-kinetic temperature, analyte and argon atom and ion concentrations, and analyt e emission intensities. These parameters can be measured on the same p lasma running under identical operation conditions. The techniques to probe the basic plasma properties include Thomson scattering (for elec tron concentration and temperature), Rayleigh scattering (for heavy-pa rticle temperature), computer-aided optical tomography (for three-dime nsional emission maps), and laser-induced saturated fluorescence (for analyte and argon atom and ion number densities). A brief description of these techniques is presented. Also, a new approach to determining absolute number densities from fluorescence measurements is introduced . This novel method is based on normalizing a measured fluorescence in tensity by the room-temperature Rayleigh-scattering signal. (C) 1997 E lsevier Science B.V.