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Proceedings Paper

An electronically collimated portable gamma-ray detector for locating environmental radiation sources
Author(s): Kenneth L. Matthews II; Blair M. Smith; Adam W. Lackie; William H. Hill Jr.; Wei-Hsung Wang; Michael L. Cherry
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Paper Abstract

We are developing a detector system for locating environmental radiation sources. The design emphasizes compact size (ideally hand-held), wide field of view and high detection efficiency, and uses cadmium-zinc-telluride (CZT) detectors and electronic collimation via Compton-scatter detection. The detector design is a 6-sided box with a primary scatter detector on one end. GEANT4 simulations, allowing variations of detector parameters and source energies/locations, provided performance estimates. A partial prototype, using 16x16-pixel 38x38x5-mm3 CZT detectors, was developed and tested. Two methods to calculate source direction in real-time from the Compton scatter data were evaluated: (1) filtered backprojection of cones onto a sphere; (2) intersection with the sphere of bounding boxes circumscribed around the cones. Simulation results of the 6-sided box with the current CZT modules indicated 1-5% of incident gamma rays produce valid direction angles, with an angular resolution of ~15°. The directional algorithms allowed a FOV (directional error <10°) of approximately ±60°. The direction algorithms converge on a source direction estimate in as few as 100 detected events. With improvements in detector energy and spatial resolution, reasonable performance seems achievable for a range of radioisotopes, e.g., from Am-241 through Co-60.

Paper Details

Date Published: 30 August 2006
PDF: 12 pages
Proc. SPIE 6319, Hard X-Ray and Gamma-Ray Detector Physics and Penetrating Radiation Systems VIII, 63190H (30 August 2006); doi: 10.1117/12.683568
Show Author Affiliations
Kenneth L. Matthews II, Louisiana State Univ. (United States)
Blair M. Smith, Louisiana State Univ. (United States)
Adam W. Lackie, Louisiana State Univ. (United States)
William H. Hill Jr., Louisiana State Univ. (United States)
Wei-Hsung Wang, Louisiana State Univ. (United States)
Michael L. Cherry, Louisiana State Univ. (United States)

Published in SPIE Proceedings Vol. 6319:
Hard X-Ray and Gamma-Ray Detector Physics and Penetrating Radiation Systems VIII
F. Patrick Doty; Larry A. Franks; Arnold Burger; H. Bradford Barber; Hans Roehrig; Ralph B. James, Editor(s)

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