A COMBINED THOMSON-RAYLEIGH SCATTERING DIAGNOSTIC USING AN INTENSIFIED PHOTODIODE ARRAY

A combined Thomson-Rayleigh scattering device is discussed. It consists of a Nd:YAG laser as a light source in combination with a multichannel detection technique consisting of a gated light amplifier in combination with an optical multichannel analyzer. Special attention is focused on the analysis of the measured spectra. Including convolution methods and taking into account weak coherent effects increases the dynamic range and the accuracy of the measured electron density n(e) and temperature T(e) and neutral particle density no. Accuracies of 1%-4% for n(e), 2%-6% for T(e), and 10%-50% for n0 depending on the plasma condition are obtained. The dynamic range for n(e) is 7 X 10(17)-10(21) m-3, for n0 is 10(20)-10(23) m-3 and for T(e) is 1000-50 000 K.