D. P. McNutt

A rocket-borne liquid helium-cooled infrared telescope. I: dewar and optics.

A telescope for rocket-borne ir astronomy is described. It consists of a 166-mm cassegrainian telescope cooled to liquid helium temperature and operated with a total radiation chopper. Details of the optical, cryogenic, and electronic designs are given.

Cryogenic Infrared Grating Spectrometer

A liquid-helium-cooled Ebert-Fastie grating spectrometer for use in a sounding rocket is described. Twelve detectors and associated filters separate the 5-70-microm spectral range into twelve intervals, each of which is scanned as the grating is rotated. The instrument was launched into an aurora from Fort Churchill, Canada, but a cryogenic failure occurred early in the flight, and only a small amount of data was obtained.

A Rocket-Borne Liquid Helium-Cooled Infrared Telescope. II: Photoconductive Detectors

In the absence of a thermal radiation background, it is possible to obtain a very high responsivity with far ir extrinsic photoconductive detectors. Using a low noise liquid helium-cooled preamplifier, we have obtained an NEP of 10(-14) W Hz(-(1/2)) for Ge: Ga at 100 micro in an instrument designed for rocket ir astronomy. The limiting noise factor appears to be generation recombination noise due to thermal excitation of other impurities present in the germanium.

Spectral response of n-type InSb in the submillimeter range

Abstract The spectral response of an n-type InSb bolometer and a Golay detector were compared between about 10 and 100 cm−1. The optical systems were held nearly constant and major wave number dependent deviations were removed from the data. The relative responsivities are given with the detector, cathode followers, and preamplifiers treated as a single component with the detector.

Passive Cone Angle Amplifier for Sounding Rockets

A passive mechanical device for slowly expanding the yaw cone of a spinning sounding rocket is described in mathematical detail. The equations of motion for the system are solved and approximations useful for design are developed. The device has been used for sky scanning in the infrared and results of a test flight are presented.

Comparison of Photoconductive-Bolometer Detectors on an Airborne System

A Ge:Ga photoconductive detector at l00μm and a GaAs epitaxial photoconductive detector at 285μm has been optimized for sensitivity comparison with a conventional bolometer system of Yerkes Observatory. The response of the photoconductive detectors were studied in the laboratory under two background conditions: baffles and Fabry Optics. A direct comparison of the photoconductive detectors to the bolometer will be made on the 91.5 cm telescope aboard the NASA C-141 Airborne Infrared Observatory.