The dependence upon irradiance of the steady-state reflectance, absorptance, and transmittance of pure SF6 gas and of SF6-He mixtures has been studied at normal incidence, and compared with the predictions of the previous theoretical paper. The radiator was a CO2 laser operating at the center of the P20 line (wavelength 10.591035 μm) providing irradiances of 0.9, 1.6, 3.3, 6.2, 17, 26, 53, and 103 kWm−2. The SF6 pressures employed were 33, 45, 57, and 81 Pa (pure) and 40 and 74 Pa mixed with 156 and 64 Pa of He, respectively. The experimental results, averaged over several cell lengths to eliminate interference effects from the surfaces of the KCl cell windows, agreed with the theoretical predictions to within 0.0058 for reflectance and within 0.028 for transmittance (68% confidence levels) over the entire range of pressures and irradiances employed. The experimental error in the measurements was estimated to be less than 0.005 for the reflectance and 0.01 for the transmittance. These results constitute excellent confirmation of the theory, considering that all data used as input to the computational algorithm were taken from the literature (or measured or calculated independently) with no adjustable parameters.
© 1977 Optical Society of AmericaFull Article | PDF Article
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