Analysis of Source Detectability With Fast-Moving Sensors

We provide a comprehensive upper-bound analysis of radioactive source detection capabilities by characterizing performance of an idealistic system configuration. Specifically, we analyze scenarios where the sensors are moving relative to the source. We first present a simplified analytical model which allows us to compute a rough, yet comprehensive estimate of the minimum detectable amount (MDA) of source material for any given configuration. To our knowledge, this is the first analytical model to simultaneously account for and mutually relate sensor design parameters, physical properties of the environment, desired detection system performance, and application characteristics, all in one equation. For instance, for flyover applications, the model shows that if we reduce altitude of flight by half, we can increase the speed of the pass-by by a factor of approximately 8, while maintaining the same source detectability. We show the distributions of MDA that are feasible to attain across a variety of common sensor transport modalities and designs. By demonstrating what can possibly be attained in terms of detectability of sources of radiation when the ideal conditions are met, we can inform system design and perform comparative analysis of alternative designs, in particular. Our results are directly applicable to support system design, engineering, policy, and strategy decisions. They can mitigate risks and prevent time, resources, and funds from being directed toward attempts to achieve unrealistic goals in the broad range of applications of radiation detection technology.