A Prototype Compton Camera Array for Localization and Identification of Remote Radiation Sources

A functional prototype two-plane Compton camera array for localization and identification of remote radiation sources, consisting of four PVT and four NaI(Tl) scintillation detectors with PMT readout, is presented. The large-volume, 76 × 76 ×76 mm scintillators provide a broad field of view for scattered photons and facilitate maximum efficiency at moderate cost. Each detector is equipped with a voxelSPEC, a compact electronic module that provides high voltage for the PMT, signal processing, detector stabilization, and an Ethernet communication interface. The voxelSPEC delivers list-mode event data with nanosecond precision timing over non-proprietary Ethernet and makes a system extension very easy. A software package has been developed for real-time data processing and image reconstruction. Advantages in the hard- and software allow stable, unattended operation of the camera array for many days, and provide easy-to-read information on the radiation source in real time. Measurements with the prototype array have been performed for a few standard scenarios and geometries to verify the model predications obtained by Monte-Carlo simulations. Simulations have been further performed to explore larger camera arrays with 2 × 4 × 4, 2 × 8 × 8, 2 × 10 × 10, 2 × 13 × 13 and 2 × 16 × 16 detectors.