Kinetic and Extraction Measurements on 12C18O2

Abstract : A candidate transmitter source for a space bourne pulsed Doppler wind-sensing lidar is the Carbon dioxide laser. To minimize beam propagation losses due to atmospheric CO2 extinction, a rare isotope is used as the active laser molecule. The particular rare isotope and laser transition is further determined by choosing a transition wavelength that minimizes the propagation losses and maximizes the backscatter coefficient of the atmospheric aerosol background. The 12C1802 isotope R(20) transition at 9.11 micrometer coincides with a Sellmier resonance of predominant aerosol constituents and papers to be the optimum choice. The performance of a 12C18O2 laser capable of fulfilling the global wind-sensing mission was addressed analytically and experimentally in this study. Gain and collisional deactivation rate measurements were conducted in an x-ray preionized, self-sustained discharge laser testbed, by observing the effect of propagation through the laser medium on a cw 12C18O2 laser probe beam. The kinetic rates derived from the measurements deviated significantly from similar published measurements for the abundant 12C16O2 isotope. The new rate information was input into an existing kinetics code, and laser parameters required for a 10 J/pulse and 3 microsecond duration pulse were deduced.