A novel diagnostic for time-resolved spectroscopic argon and lithium density measurements

A new diagnostic technique for determining neutral gas and metal vapor densities over a wide pressure range with high time resolution is described. A compact, current-stabilized hollow cathode/anode discharge is use to ionize the gas and/or trace impurity to be analyzed. We report proof-of-principle operation of the diagnostic in a well characterized argon discharge in the pressure range 6.7–265 Pa. The intensity ratio of neutral and singly ionized argon lines (IAr I/IAr II) is shown to increase monotonically with the neutral argon density. In a second experiment, absolute neutral lithium vapor densities have been measured using this diagnostic.