Technique for Determining Density Distribution in Low Pressure, High Temperature Gases

A new technique for measuring the point-by-point density distribution in a high temperature gas that is applicable to plasma jet facilities and hypersonic wind tunnels has been developed. An electron beam probe is directed into the plasma, and the observed number of bremsstrahlung x rays created in a given segment of the beam via electron-gas atom interaction provides a direct measurement of gas density in terms of the number of atoms per unit volume. The method provides good spatial resolution, and density determination is independent of gas temperature, chemical form, and the degree of dissociation and ionization.