The LANL prototype Compton gamma-ray imager: design and image reconstruction techniques

Today we face serious terrorist threats from radiological dispersion devices, improvised nuclear devices, and unsecured nuclear materials. It is imperative that we develop and implement radiation detection technology capable of locating and tracking nuclear material moving across and within our borders. Common detectors available today suffer from large background rates and have only minimal ability to localize the position of the source without the use of mechanical collimators, which reduces efficiency. Imaging detectors using the Compton scattering process have the potential to provide greatly improved sensitivity through their utility to reject off-source background. We are developing a prototype device using commercially available detector systems to demonstrate the Compton imaging technology. Here we discuss the concept of our detector design and results from Monte Carlo simulations of our prototype detector. We present a novel approach to Compton scatter image reconstruction based on adaptation of a technique from the astronomy community.