Covert system for detecting nuclear dirty bombs in public venues

Background In the past two decades, the potential threat of a radiological dispersal device (RDD) or “dirty bomb,” which combines conventional explosives with radioactive material, has been a concern for counterterrorism efforts. The accessibility of radioactive materials used in various applications, such as medicine, industry, and research, makes RDDs a viable weapon of choice for terrorists. While the radiation released from an RDD is generally not lethal beyond a short range, the long-term health, environmental, and psychological effects of radiation release will have an impact on the future of a society. Providing proactive security measures will aid in the deterrence of potential radiological terrorist threats. Methods The use of commercial off-the-shelf detectors and GPS modules can be integrated with software to provide the approximate location of a radioactive anomaly. With the strategic placement of a circular array of 4-inch × 4-inch Thallium dopped Sodium-Iodide (NaI) in a façade of a full trashcan, it is possible to determine if, when, and the general direction of a hand- carried threat entering a venue. A supplemental detector containing a Cesium-Iodide (CsI) crystal and a GPS module fitted to a plate carrier vest can further refine the location of a threat. In tandem, these two designs are capable of providing the RDD screening that is currently lacking in public. Conclusions While a true threat may contain a radiation source well in the hundreds of Curies, the designs selected are tested and calibrated to 1-microcurie button sources. Which provides scaled results that indicate the possibility for the deployment of such a detection scheme in a venue. Although the devices tested are limited by commercial GPS resolution, the ability for both designs to determine the presence and approximate location of a button source within 10 feet is promising for further larger scale tests.