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Proceedings Paper

Detectors and focal plane modules for weather satellites
Author(s): A. I. D'Souza; E. Robinson; S. Masterjohn; P. Ely; V. Khalap; S. Babu; D. S. Smith
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Paper Abstract

Weather satellite instruments require detectors with a variety of wavelengths ranging from the visible to VLWIR. One of the remote sensing applications is the geostationary GOES-ABI imager covering wavelengths from the 450 to 490 nm band through the 13.0 to 13.6 μm band. There are a total of 16 spectral bands covered. The Cross-track infrared Sounder (CrIS) is a Polar Orbiting interferometric sensor that measures earth radiances at high spectral resolution, using the data to provide pressure, temperature and moisture profiles of the atmosphere. The pressure, temperature and moisture sounding data are used in weather prediction models that track storms, predict levels of precipitation etc. The CrIS instrument contains SWIR (λc ∼ 5 μm at 98K), MWIR (λc ∼ 9 μm at 98K) and LWIRs (λc ∼ 15.5 μm at 81K) bands in three Focal Plane Array Assemblies (FPAAs).

GOES-ABI contains three focal plane modules (FPMs), (i) a visible-near infrared module consisting of three visible and three near infrared channels, (ii) a MWIR module comprised of five channels from 3.9 μm to 8.6 μm and (iii) a 9.6 μm to 13.3 μm, five-channel LWIR module. The VNIR FPM operates at 205 K, and the MWIR and LWIR FPMs operate at 60 K. Each spectral channel has a redundant array built into a single detector chip. Switching is thus permitted from the primary selected array in each channel to the redundant array, given any degradation in performance of the primary array during the course of the mission. Silicon p-i-n detectors are used for the 0.47 μm to 0.86 μm channels. The thirteen channels above 1 μm are fabricated in various compositions of Hg1-xCdxTe, and in this particular case using two different detector architectures. The 1.38 μm to 9.61 μm channels are all fabricated in Hg1-xCdxTe grown by Liquid Phase Epitaxy (LPE) using the HDVIP detector architecture. Molecular beam epitaxy (MBE)-grown Hg1-xCdxTe material are used for the LWIR 10.35 μm to 13.3 μm channels fabricated in Double layer planar heterostructure (DLPH) detectors. This is the same architecture used for the CrIS detectors.

CrIS detectors are 850 μm diameter detectors with each FPAA consisting of nine photovoltaic detectors arranged in a 3 x 3 pattern. Each detector has an accompanying cold preamplifier. SWIR and MWIR FPAAs operate at 98 K and the LWIR FPAA at 81 K, permitting the use of passive radiators to cool the detectors. D* requirements at peak wavelength are ≥ 5.0E+10 Jones for LWIR, ≥ 9.3E+10 Jones for MWIR and ≥ 3.0E+11 Jones for SWIR. All FPAAs exceeded the D* requirements. Measured mean values for the nine photodiodes in each of the LWIR, MWIR and SWIR FPAAs are D* = 5.3 x 1010 cm-Hz1/2/W at 14.0 μm, 1.0 x 1011 cm-Hz1/2/W at 8.0 μm and 3.1 x 1011 cm-Hz1/2/W at 4.64 μm.

Paper Details

Date Published: 2 May 2016
PDF: 15 pages
Proc. SPIE 9881, Earth Observing Missions and Sensors: Development, Implementation, and Characterization IV, 988115 (2 May 2016); doi: 10.1117/12.2228898
Show Author Affiliations
A. I. D'Souza, DRS Sensors & Targeting Systems, Inc. (United States)
E. Robinson, DRS Sensors & Targeting Systems, Inc. (United States)
S. Masterjohn, DRS Sensors & Targeting Systems, Inc. (United States)
P. Ely, DRS Sensors & Targeting Systems, Inc. (United States)
V. Khalap, DRS Sensors & Targeting Systems, Inc. (United States)
S. Babu, NASA Goddard Space Flight Ctr. (United States)
D. S. Smith, Harris Corp. (United States)

Published in SPIE Proceedings Vol. 9881:
Earth Observing Missions and Sensors: Development, Implementation, and Characterization IV
Xiaoxiong J. Xiong; Saji Abraham Kuriakose; Toshiyoshi Kimura, Editor(s)

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