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### Proceedings Paper

Mercuric iodide x-ray and gamma-ray detectors for astronomy
Author(s): Lodewijk Van den Berg; John S. Sandoval; Ronald D. Vigil; John D. Richards; Fred P. Vaccaro; Martin Hykin; Raymond P. DeVito
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Paper Abstract

The recent technological developments and availability of mercuric iodide detectors have made their application for astronomy a realistic prospect. Mercuric iodide, because of its high resistivity and high density, can be used in a variety of astronomy instrumentation where high spectral resolution, low noise levels, stability of performance, resistance to damage by charged particles and overall ruggedness are of critical importance. X-ray detectors with areas of 12 to 100 mm square and 1 mm thickness have absorption efficiencies approaching 100% up to 60 keV. The spectral resolution of these detector's ranges from 400 eV to 600 eV at 5.9 keV, depending on their area, and the electronic noise threshold is less than 1.0 keV. Gamma ray detectors can be fabricated with dimensions of 25 mm x 25 mm x 3 mm. The spectral resolution of these detectors is less than 4% FWHM at energies of 662 keV. Because of the high atomic numbers of the constituent elements of the mercuric iodide, the full energy peak efficiency is higher than for any other available solid-state detector that makes measurements up to 10 MeV a possibility. The operation of gamma ray detectors has been evaluated over a temperature range of -20 through + 55 degrees Celsius, with only a very small shift in full energy peak observed over this temperature range. In combination with Cesium Iodide scintillators, mercuric iodide detectors with 25 mm diameter dimensions can be used as photodetectors to replace bulky and fragile photomultiplier tubes. The spectral resolution of these detectors is less than 7% FWHM at 662 keV and the quantum efficiency is larger than 80 % over the whole area of the detector.

Paper Details

Date Published: 25 January 2002
PDF: 6 pages
Proc. SPIE 4497, X-Ray and Gamma-Ray Instrumentation for Astronomy XII, (25 January 2002); doi: 10.1117/12.454215
Show Author Affiliations
Lodewijk Van den Berg, Constellation Technology Corp. (United States)
John S. Sandoval, Constellation Technology Corp. (United States)
Ronald D. Vigil, Constellation Technology Corp. (United States)
John D. Richards, Constellation Technology Corp. (United States)
Fred P. Vaccaro, Constellation Technology Corp. (United States)
Martin Hykin, Constellation Technology Corp. (United States)
Raymond P. DeVito, Constellation Technology Corp. (United States)

Published in SPIE Proceedings Vol. 4497:
X-Ray and Gamma-Ray Instrumentation for Astronomy XII
Kathryn A. Flanagan; Oswald H. W. Siegmund, Editor(s)