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Proceedings Paper

Detector signal relaxations and their correction: the Si:Ga bulk detectors of the CRISTA instrument
Author(s): Manfred Ern; Klaus Ulrich Grossmann; Dirk Offermann
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Paper Abstract

The CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) instrument measured atmospheric trace gas emissions in the infrared using the limb scanning technique. For the first time three viewing directions were used by a satellite instrument in near-earth orbit (300 km) to obtain an unprecedented spatial density of the daily global measurement net. The high measurement speed needed for an enhanced horizontal resolution was achieved by cooling the instrument with supercritical and subcooled helium and by using Si:Ga bulk or Si:As blocked impurity band (BIB) detectors for the wavelength range 4-17 micrometers and Ge:Ga bulk detectors for longer wavelengths. The detectors were operated at temperatures between 2.5 and 13 Kelvin. Under these conditions the signal of the detectors shows non-stationary effects (relaxation effects) degrading measured spectra to some extent.These effects are difficult to account for as they can only be described by using at least 6 parameters depending on signal height and illumination history. In this paper an empirical model to correct the non-stationary effects of the Si:Ga detectors is presented. The model is based on measured signal responses after step-like illumination changes. Several tests using different data sets show that the model works well under various conditions.

Paper Details

Date Published: 8 February 2002
PDF: 11 pages
Proc. SPIE 4486, Infrared Spaceborne Remote Sensing IX, (8 February 2002); doi: 10.1117/12.455100
Show Author Affiliations
Manfred Ern, Univ. Wuppertal (Germany)
Klaus Ulrich Grossmann, Univ. Wuppertal (Germany)
Dirk Offermann, Univ. Wuppertal (Germany)

Published in SPIE Proceedings Vol. 4486:
Infrared Spaceborne Remote Sensing IX
Marija Strojnik; Bjorn F. Andresen, Editor(s)

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