Gamma-Ray Source Detection With Small Sensors

Large detectors can give better background characterization and can detect radiation sources at larger standoff distances. Small detectors, on the other hand, are less expensive, can often get closer to source materials, and can access places that large detectors cannot (e.g., indoor environments). We systematically quantify the impact of detector size and number on source detection in area search applications. We analyze theoretical upper bounds on source detectability and establish first-order approximations thereof. We demonstrate that these approximations give good comparisons of different choices of sensor size and number for practical source detection algorithms using semisynthetic data. Our results indicate that multiple small detectors, in conjunction, can offer superior overall operational utility compared with a single large detector. Finally, we identify differences in detector response and likelihood of a close approach as key determinants of the relative utility of small sensors.