QUANTITATIVE MEASUREMENTS OF OXYGEN-ATOM DENSITY USING LIF

A pulsed atomic oxygen source, used to simulate oxidization mechanisms of spacecraft surface protective material (CASOAR), is probed by LIF. LIF measurements of oxygen atom density were first conducted in the p ostdischarge of an O2 low-pressure microwave excited plasma. It appear s that the fluorescence yield depends strongly on the laser beam focus ing conditions. This dependence must be taken into account for proper analysis of the experiment. ThUS, LIF measurements appear to be quanti tatively correct and consistent with the results of NO2 titration.