Improvements In Long Path Absorption Cell Measurements.
Research and development technical rept.,
ARMY ELECTRONICS COMMAND FORT MONMOUTH N J
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Improvements which greatly reduce the data acquistion time and increase the accuracy of long-path absorption cell measurements upon which the choice and further development of many Army laser-based systems depend are discussed. path differencing, a new technique for measuring absorption coefficients, is described. Path differencing effectively gives the massive cells and intricate optical and detection systems used in long-path absorption cell experiments the real-time calibration of double-beam spectrometer systems. This calibration results in a factor of 4 to 5 in improvement in reproducibility. Techniques of weighted averages are discussed for obtaining best fit absorption data, and a detection and correction scheme for system nonlinearities is given. A method for determining errors in absorption coefficients from data at different partial pressures of an absorbing gas and characterizing nonlinear pressure dependencies is also included. Author
- Atmospheric Physics
- Lasers and Masers