A 10 micron heterodyne receiver for ultra high resolution astronomical spectroscopyAn improved CO2 laser heterodyne spectrometer is examined. The present system uses reflective optics to eliminate refocusing at different wavelengths, and the local oscillator is a line-center-stabilized isotopic CO2 laser. A tunable diffraction grating makes possible easy and rapid selection of over 50 transitions per isotope of CO2. The IF (0 to 1.6 GHz) from the HgCdTe photomizer is analyzed by a 128-channel filter bank, consisting of 64 tunable 5-MHz filters and 64 fixed 25-MHz RF filters. These filters provide resolving powers of about 1,000,000 to 10,000,000 and velocity resolution of 50 to 250 m/sec; their output is synchronously detected, integrated, multiplexed and stored in a buffer memory for the desired integration period. Kitt Peak observations show the wide spectral coverage, wide mixer and electronics bandwidth, and high sensitivity of the system.
Document ID
19810043342
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Buhl, D. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Chin, G. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Faris, J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kostiuk, T. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mumma, M. J. (NASA Goddard Space Flight Center Infrared and Radio Astronomy Branch, Greenbelt, Md., United States)
Zipoy, D. (Maryland, University College Park, Md., United States)