Abstract

Previous work^1,2 has shown that laser-induced desorption (LID) can prove useful for the determination of surface contamination. Because of the nature of small spot sampling, however, it proved rather difficult to gather statistically significant data. Now that automation of LID has been accomplished, a detailed study of CaF₂ is in progress. As in the referenced work, the samples will be irradiated with the focused beam from an HF/DF laser inside an ultrahigh vacuum chamber. The molecules desorbed from the sample surface are largely contained in a glass envelope that surrounds the ionizer of a quadrupole mass analyzer. For this study, water will be the contaminant monitored on etched, bulk CaF₂. Heavy water from bulk alkali halides as well as from thin CaF₂ films also will be studied in an attempt to determine the mechanism associated with the LID process.

© 1988 Optical Society of America