Liquid Nitrogen-Cooled Fourier Transform Spectrometer System for Measuring Atmospheric Emission at High Altitudes

Abstract A cryogenically cooled FTS system capable of a spectral resolution of 0.06 cm−1 is described. The entire interferometer is operated at LN2 temperature with the exception of the Ge:Cu detector, which is cooled to below 10 K. In order to maintain alignment while the unit is cold, a cat's eye optical system was employed, and all mechanical components fabricated from the same stress-relieved steel. The system was constructed to measure atmospheric emission spectra from a balloon platform. The requirements on the electronics and data handling systems imposed by the remote operation and balloon environment are discussed. Some data obtained on a balloon flight launched on 23 October 1983 are presented. These show that the instrument has the sensitivity to measure the atmospheric emission at high altitudes with the spectral resolution desired (0.06 cm−1).