Detection and Analysis of Uncharged Particles Using Consumer-grade CCDs

摘要

In the current climate of increased global terrorism, the threat of a radiological incident is becoming more realistic than ever, and as such, the necessity of early-warning detection is paramount to national security. To assist with this need, we have investigated the detection of uncharged particle emissions from radiological sources using charged-coupled devices (CCDs), which are contained within a variety of products, including consumer cellphones and traffic cameras. Because the CCD is intrinsically sensitive to charge accumulation as a result of linear energy transfer by the incident particles, each event can be counted and quantified using video-image processing and an estimated energy band assessed by the properties of the pixels. In an effort to make this process applicable to the widest possible range of CCDs available, this experiment was conducted using low-quality CCDs contained within consumer-grade, budget web cameras. Within a Pu-239-Be neutron howitzer, particles were detected using several camera models: Gigaware X76, Z76 and Logitech C170, C270. Particle detection events were counted by post-processing with Matlab, and an efficiency for each CCD was determined relative to both a theoretical flux model and a calibrated He-3 tube detector. The relative detection efficiencies for the cameras tested fell within the range 14-18% and showed a linear correlation between incident energy and pixel response.