Radiological Security for Mass Events

Increasingly, radiological security has become an integral aspect of mass event planning, especially of political summits attended by high-class dignitaries. This talk outlines a few best practices, typical equipment, and sensible interfaces between private security contractors and government authorities. In a first step a perimeter must be defined. All points of entry through the perimeter that allow access to the venue should be monitored with suitable equipment: All pedestrians as well as vehicles entering the perimeter should be conducted to pass through a Radiation Portal Monitor (RPM). RPMs exist as relocatable, man-portable devices. They can be set up within hours to monitor passageways. RPMs are a means of primary screening. Vehicles or pedestrians triggering an alarm in an RPM need to be taken aside for secondary screening. Alarm resolution may be performed using a Radioisotope Identification Device (RIID). RIIDs are available in the form of handheld detectors. While RPMs can be operated by personnel having minimal specific training, personnel operating RIIDs need to be sufficiently knowledgeable in the field of radiation protection to have an overview of typical medical isotopes, naturally occurring radioactive materials (NORM), and actual threat sources. If an alarm cannot be resolved by means of a RIID, the case should be handed over to governmental authorities. Once a perimeter has been established and access is controlled, the venue can be searched for radiological threats. This process is called profiling. Profiling can efficiently be conducted using one or several drone-borne gamma detectors running a systematic pattern covering the entire area. The goal is not just to discover concealed radiological threats, but also to understand the levels of background radiation for the entire venue. Visual inspection is equally necessary to discover shielded sources that could be hidden in places like trashcans. Inspection of such potential caches, as well as the resolution of any alarms arising in the profiling, can be performed using a RIID. Should no drones be available for profiling, a task can be performed in a more laborious manner by a team of security personnel each equipped with a Personal Radiation Detector (PRD), a device that does not necessitate excessive training in order to be effectively used. Networked PRDs are well suited for this purpose. Drone-based profiling of a venue may be conducted using novel compact and modular plastic scintillation detectors coupled to the drones. Recently, there has been development towards these detectors for detection of illicit trafficking of radionuclides, resulting in rugged SiPM based gamma detection systems to efficiently detect gamma radiation in a wide range of energies. Due to their modularity and ease of scalability, these gamma detectors can also be used in a variety of radiation monitoring systems with different scales, ranging from hand-held contamination monitoring systems up to radiation portal monitors. Once the venue has been profiled, guests can be permitted to enter the perimeter, always passing through RPMs. RPMs capable of isotope categorization serve to minimize the number of alarms and thus increase throughput. Note that besides being a tool for interdicting radiological threats, RPMs also have a deterrence value. During the event, a team of security personnel equipped with PRDs – ideally networked PRDs –may be introduced into the crowd to increase chances of detection. (author)