TOMOGRAPHICALLY RESOLVED IONIZATION TEMPERATURES AND ELECTRON-DENSITIES IN THE INDUCTIVELY-COUPLED PLASMA DETERMINED BY THE LINE-TO-CONTINUUM METHOD

This article is an electronic publication in Spectrochimica Acta Elect ronica (SAE), the electronic section of Spectrochimica Acta Part B (SA B). The hardcopy text is accompanied by three disks with data files wi th the hardcopy paper in Word 5.0 and ASCII format, and a disclaimer. The text details the purpose of the work and the structure of the thre e-dimensional Ar ionization temperature and electron number density da ta files. The line-to-continuum method was used to evaluate the spatia l distribution of Ar ionization temperatures, T(ion), and electron num ber densities, n(e), within a dry Ar inductively coupled plasma (ICP). The emission measurements were spatially resolved in three dimensions by reconstruction algorithms for computed tomography. The 40.68 MHz A r ICP was operated at applied r.f. power levels of 0.75 and 1.0 kW. Th e reconstructed distributions of Ar I line emission (430.0 nm) and con tinuum emission (428.6 nm) show good reproducibility over a series of five replicate runs. Argon ionization temperatures remain within a 650 0-8500 K range throughout the continuum-emission cone of the plasma. D eviations from this temperature range occur in the central channel and around the outer edge of the plasma. Low in the plasma, the central-c hannel T(ion) is cooler than 6000 K. Along the outer edge of the plasm a, the line-to-continuum ratio becomes small; this low ratio results i n erroneously high temperatures (>12000 K). The errors in T(ion) appea r to be due to reproducible artifacts in the reconstruction process th at lead to low Ar I line-emission readings along the outer edge of the plasma. Electron densities show a maximum of 8.5 x 10(14) CM-3 and 1. 2 x 10(15) cm-3 at 0.75 and 1.0 kW, respectively. Electron number dens ities were much better behaved than T(ion) due to their dependence on the square-root of continuum measurements and only the fourth-root of T(ion).