Measurement of gas temperature gradients using Raman scattering spectroscopy

The application of Raman scattering (inelastic light scattering) spectroscopy to the measurement of gas temperature and its gradient in hot flowing gas systems is described, using experiments on a chemical vapor deposition system as an example. Apparatus is described and data are presented showing temperature gradients in the range 280 C to 950 C with RMS deviations of 14°C on a spatial scale of 100μm. Advantages of the system are its ability to make measurements in a small well defined volume and to do this totally without perturbation of the system. The principle disadvantage is a relatively low rate of data acquisition.