Optimization of a compton suppression detector system using CdZnTe and liquid scintillators

The goal of this work is to explore and optimize a gamma-ray detection system combining cadmium-zinc-telluride (CZT) and organic liquid scintillator into a single detector for homeland security applications. The size and location of the CZT cell as well as 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 a newly-developed algorithm that relies on 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 a factor of 3.0 relative to a bare CZT cell at a total detector weight of 16 lbs. (authors)