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High-resolution imaging gamma-ray spectroscopy with externally segmented germanium detectorsExternally segmented germanium detectors promise a breakthrough in gamma-ray imaging capabilities while retaining the superb energy resolution of germanium spectrometers. An angular resolution of 0.2 deg becomes practical by combining position-sensitive germanium detectors having a segment thickness of a few millimeters with a one-dimensional coded aperture located about a meter from the detectors. Correspondingly higher angular resolutions are possible with larger separations between the detectors and the coded aperture. Two-dimensional images can be obtained by rotating the instrument. Although the basic concept is similar to optical or X-ray coded-aperture imaging techniques, several complicating effects arise because of the penetrating nature of gamma rays. The complications include partial transmission through the coded aperture elements, Compton scattering in the germanium detectors, and high background count rates. Extensive electron-photon Monte Carlo modeling of a realistic detector/coded-aperture/collimator system has been performed. Results show that these complicating effects can be characterized and accounted for with no significant loss in instrument sensitivity.
Document ID
19930048949
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Callas, J. L.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Mahoney, W. A.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Varnell, L. S.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Wheaton, W. A.
(JPL Pasadena, CA, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1993
Publication Information
Publication: Review of Scientific Instruments
Volume: 64
Issue: 1
ISSN: 0034-6748
Subject Category
Instrumentation And Photography
Accession Number
93A32946
Distribution Limits
Public
Copyright
Other

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