Infrared Optical Properties of Bipropellant Cryocontaminants
Interim rept. 1 Oct 1977-15 Mar 1979
ARO INC ARNOLD AFS TN
Pagination or Media Count:
The infrared spectral transmittance of cryofilms formed by MMH, N2O4, and N2H4 propellants was measured. These films were cryopumped on 20 and 77K germanium substrates and ranged in thickness from 0.25 to 9 microns the deposition pressure for the films was approximately 1 x 10-7 torr. Transmission spectra were obtained for the 500 to 3700 wavenumber range using a Fourier transform spectrometer. Values of the complex index of refraction for the cryodeposits were derived from the experimental data using an analytical model and a nonlinear least-squares method. The analytical model treats the germanium as a thick, noninterfering film and the deposit as a thin film. Results from the least-squares method are also compared with a Kramers-Kronig determination of the real part of the index of refraction. The optical properties of such cryofilms are essential for predicting the degradation of cryocooled optical surfaces contaminated by liquid propellant exhaust plumes.
- Infrared Detection and Detectors
- Liquid Propellant Rocket Engines
- Liquid Rocket Propellants