Monte Carlo Optimization of a Two-Plane Compton Imager

Year
2009
Author(s)
B.A. Maestas - University of Michigan
P.R. Stanfield - University of Michigan
M. Flaska - University of Michigan
S.A. Pozzi - University of Michigan
A. Guergueiev - ICx Radiation Inc.
C.M. Herbach - ICx Radiation Inc.
J. Stein - ICx Radiation Inc.
Abstract
Compton cameras have been used for astronomical and medical imaging applications as early as the 1970s. Recent interest in their potential for the detection and localization of special nuclear material and radioactive sources has led to increasing investigations. In this work, a large area (1 m2) Compton camera consisting of two planar arrays of gamma-ray detectors was evaluated for the following materials: LaBr3, YAP, CaF2, Si, and CZT. Procedures for the optimization of plane thickness and individual detector (voxel) size are presented. Theoretical figures of merit (FOM) are developed considering the intrinsic Compton camera efficiency and angular uncertainty of the proposed system. Each material is investigated at 186, 662, and 1001 keV source energies. The MCNP-PoliMi code was used to simulate photon interactions within the voxels and an analytical technique was used to calculate angular uncertainties. Detailed interaction information provided by MCNP-PoliMi was post processed using a specialized algorithm developed to analyze detector events.