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Elementary Analysis Of Line Shapes And Energy Resolution In Semiconductor Radiation Detectors

Published online by Cambridge University Press:  10 February 2011

J. E. Toney
Affiliation:
Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213
T. E. Schlesinger
Affiliation:
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213;
B. A. Brunett
Affiliation:
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213;
R. B. James
Affiliation:
Sandia National Laboratories, Livermore, CA 94550
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Abstract

We have used an elementary statistical technique to derive a closed-form expression for the hole-tailing line shape produced by photoelectric absorption of monoenergetic radiation in a semiconductor X-ray/γ-ray detector. In the case of compound semiconductors, where the drift length for electrons is much greater than that for holes, the line shape is given by a type of power law, except for a small region very near the photopeak. This analytical result agrees well with Monte Carlo simulations and is used to extract approximate μτ products from a 57Co pulse height spectrum. We also present an expression for the maximum obtainable energy resolution of a semiconductor detector in the presence of leakage current noise and intrinsic statistical fluctuations as a function of material parameters, along with a chart of the optimal band gap as a function of temperature and photon energy. Based on these considerations, the optimal band gap for room-temperature operation is approximately 2.0 eV.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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