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Induced radioactivity in LDEF componentsThe systematics of induced radioactivity on the Long Duration Exposure Facility (LDEF) were studied in a wide range of materials using low level background facilities for detection of gamma rays. Approx. 400 samples of materials processed from structural parts of the spacecraft, as well as materials from onboard experiments, were analyzed at national facilities. These measurements show the variety of radioisotopes that are produced with half-lives greater than 2 wks, most of which are characteristic of proton induced reactions above 20 MeV. For the higher activity, long lived isotopes, it was possible to map the depth and directional dependences of the activity. Due to the stabilized configuration of the LDEF, the induced radioactivity data clearly show contributions from the anisotropic trapped proton flux in the South Atlantic Anomaly. This effect is discussed, along with evidence for activation by galactic protons and thermal neutrons. The discovery of Be-7 was made on leading side parts of the spacecraft, although this was though not to be related to the in situ production of radioisotopes from external particle fluxes.
Document ID
Document Type
Conference Paper
Harmon, B. A.
(NASA Marshall Space Flight Center Huntsville, AL., United States)
Fishman, G. J.
(NASA Marshall Space Flight Center Huntsville, AL., United States)
Parnell, T. A.
(NASA Marshall Space Flight Center Huntsville, AL., United States)
Laird, C. E.
(University of Eastern Kentucky Richmond., United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1991
Publication Information
Publication: NASA, Langley Research Center, First LDEF Post-Retrieval Symposium Abstracts
Subject Category
Atomic And Molecular Physics
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.

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