Characterization of γ -Ray Cross Talk in Cherenkov-Based Detectors for Active Interrogation Imaging Applications

In imaging arrays, the sensors are typically packed as tightly as possible to maximize spatial resolution, which leads to detector-to-detector scatter, or cross talk, adding to image noise and hindering contrast. In this paper, we compare custom-made quartz-based Cherenkov detectors with an inherent energy threshold to low-energy photons to standard sodium iodide detectors, which are typically used for x-ray detection due to their efficiency and spectroscopic capabilities. In particular, we evaluate pulse pileup and cross talk effects in high-flux applications. The quartz detectors, while having reduced intrinsic efficiency, outperform the sodium iodide with regards to pileup and cross talk. Simulation further shows that even at a 4 mm edge-to-edge separation, cross talk contributes less than 2% of the total signal in Cherenkov detectors.