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Infrared focal plane performance in the South Atlantic anomalyProton-induced pulse height distributions (PHD's) in Si:XX detectors were studied analytically and experimentally. In addition, a preliminary design for a flight experiment to characterize the response of Si:XX detectors to the trapped proton environment and verify PHD models was developed. PHD's were computed for two orbit altitudes for a variety of shielding configurations. Most of the proton-induced pulses have amplitudes less that about 3.5 x 10(exp 5) e-h pairs. Shielding has a small effect on the shape of the PHD's. The primary effect of shielding is to reduce the total number of pulses produced. Proton-induced PHD's in a Si:Sb focal plane array bombarded by a unidirectional 67-MeV beam were measured. The maximum pulse height recorded was 6 x 10(exp 5) pairs. The distribution had two peaks: the larger peak corresponded to 3.8 x 10(exp 5) pairs and the smaller peak to 1.2 x 10(exp 5) pairs. The maximum pulse height and the larger peak are within a factor of two of predicted values. The low-energy peak was not expected, but is believed to be an artifact of inefficient charge collection in the detector. The planned flight experiment will be conducted on a Space Shuttle flight. Lockheed's helium extended life dewar (HELD) will be used to provide the required cryogenic environment for the detector. Two bulk Si:Sb arrays and two Si:As impurity band conduction arrays will be tested. The tests will be conducted while the Space Shuttle passes through the South Atlantic Anomaly. PHD's will be recorded and responsivity changes tracked. This experiment will provide a new database on proton-induced PHD's, compare two infrared detector technologies in a space environment, and provide the data necessary to validate PHD modeling.
Document ID
19910014145
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Junga, Frank A.
(Lockheed Missiles and Space Co. Palo Alto, CA, United States)
Date Acquired
September 6, 2013
Publication Date
September 30, 1989
Subject Category
Instrumentation And Photography
Report/Patent Number
NAS 1.26:186197
LMSC-F279280
NASA-CR-186197
Accession Number
91N23458
Funding Number(s)
CONTRACT_GRANT: NAS2-12898
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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