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11 October 1989 3000 In Ga As Photodiode Multiplexed Linear Array For The Spot 4 S.W.I.R. Channel
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Abstract
SPOT 4 will be an improved version of the SPOT 1,2 and 3 earth remonte sensing satellites ; a SWIR channel is added for agriculture monitoring, and the lifetime is entended to 4 years. The SWIR sensor was designed to be fully compatible with the visible and near IR silicon CCD : - the 3000 30 μm x 30 μm pixels can be registred to the visible detectors with an accuracy better than =/= 2 μm ; - the radiometric performance (uniformity of response, dynamic range, linearity,...) is imilar to that of the visible-channel CCD ; - the operating temperature is + 5°C. The 3000-pixel sensor consists of an ultra-precise assembly of ten elementary modules comprising 300 InGaAs photodiodes and two associated CCD multiplexers on both side. One single pixel is destroyed at the splice between two adjacent modules; The ten modules are read out in sequence. The reading sequence last 3 ms. Quantum efficiency of the photodiodes is typically 65%. Noise equivalent power is 10-13 W. A dynamic range of better than 4000 is obtained at the output of the multiplexer. The histogram of output noise voltages will be presented. A map of the relative sensitivity along the array will be displayed. The cut--off wave-length depends on the In/Ga ratio in the active layer, and the operating temperature. It is 1.690 0.005 μm at +5°C. Several detectors are presently undergoing re liability tests ; no significant alteration in performance has been noticed after aging at 125°C (operating).
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. P. Moy, X. Hugon, J. Chabbal, J. De Cachard, C. Lenoble, D. Mollaret, M. Villard, and B. Villotitch "3000 In Ga As Photodiode Multiplexed Linear Array For The Spot 4 S.W.I.R. Channel", Proc. SPIE 1107, Infrared Detectors, Focal Plane Arrays, and Imaging Sensors, (11 October 1989); https://doi.org/10.1117/12.960659
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