Development of a gas laser system to measure trace gases by long path absorption techniques. Volume 1: Gas laser system modifications for ozone monitoring

Modifications of a gas laser system for long path monitoring of trace atmospheric constituents by infrared absorption are described. Modifications were made in preparation for an ozone field measurement program wherein path monitor data were compared with those from a point monitor moved along the optical path. System modifications included incorporating a digital signal processor in the system and a spatial filter in the laser beam. Spectral studies of ozone, carbon dioxide, water vapor, ethylene and ammonia are presented in connection with the selection of laser wavelengths used in the system to discriminate ozone effects from interferences. Design considerations and a proposed configuration for an isotopic CO2 laser are presented.