Optimization of a Compton Suppression Detection System Using CdZnTe and Liquid Scintillators

Year
2009
Author(s)
S. D. Clarke - School of Nuclear Engineering, Purdue University
S. D. Clarke - School of Nuclear Engineering, Purdue University
S. A. Pozzi - Department of Nuclear Engineering & Radiological Sciences
S. A. Pozzi - Department of Nuclear Engineering & Radiological Sciences
M.M. Bourne - Department of Nuclear Engineering & Radiological Sciences
M.M. Bourne - Department of Nuclear Engineering & Radiological Sciences
A, Gueorguiev - ICx Radiation
A, Gueorguiev - ICx Radiation
Abstract
The detection of characteristic gamma rays is desirable for material identification because of the uniqueness of energy emissions from each isotope. For homeland security applications, detection systems must be inexpensive, portable, and capable of collecting meaningful data in a short measurement time. In some cases, current detector systems show some limitations with respect to these needs. Therefore, the goal of this work is to explore and optimize a new gamma-ray and neutron detection system that combines cadmium-zinc-telluride (CZT) detectors with organic liquid scintillation detectors into a single detector. This detector utilizes a Compton suppression technique to isolate the photopeaks in the resulting gamma-ray spectrum, making the photopeak energies easier to identify. The dimensions of the liquid scintillator are optimized to provide a high level of suppression (highest probability of secondary gamma-ray interaction in the scintillator) relative to detector portability. The optimization is performed with an algorithm that uses the output from a series of Monte Carlo simulations using MCNP-PoliMi. In the optimized detection system, the number of photopeak counts relative to partial-energy, Compton counts was increased by varying degrees for a range of detector system weight.