Characterization of neutral density profile in a wide range of pressure of cylindrical pulsed gas jets

The neutral density profile of cylindrical gas jets is measured with a Mach-Zehnder interferometer under a wide range of backing pressures. The sensitivity of this diagnostic together with the mathematical treatment of the data allows us to measure neutral densities for argon gas as low as 10(17) cm(-3) for a 5 mm diam gas jet. (C) 2000 American Institute of Physics. [S0034-6748(00)03906-X].