Development of an HPXe-Based Nuclear Explosion Monitor

The Radiological Aerosol Sampler/Analyzer (RASA) has proven to be one of the most authoritative monitoring systems for detecting and confirming nuclear explosions, as required for implementing the Comprehensive Test Ban Treaty (CTBT). Because these monitors must be deployed worldwide under extreme environmental conditions, their reliability and ease of use is crucial to their acceptance. The first and second most probable causes of downtime for existing RASA monitors have been documented as failures of the germanium detector and of the multi-filter sampling system. Therefore, improved reliability in the detector and sampling systems, along with reduced operator support requirements, would greatly enhance the value of automated gamma spectroscopy systems for authoritative nuclear explosion monitoring. This project will apply recently-developed High-Pressure Xenon (HPXe) detectors that provide not only the sufficient energy resolution needed to address the nuclear-explosion monitoring application but also significant advantages over germanium detectors with respect to reliability, sampling system flexibility, and simplified support requirements. Phase I will measure and document the performance of state-of-the-art HPXe detectors. Preliminary designs for a simplified sampling system, and for data collection and processing, will be developed. In Phase II, a prototype HPXe nuclear explosion monitor for field application will be constructed and evaluated . Commercial Applications and other Benefits as described by the awardee: A rugged, high-resolution, room-temperature gamma ray detector, capable of supporting radionuclide identification in field applications that have complex gamma envirnoments, would offer significant benefits in several areas: continuous-duty field systems for nuclear explosion monitoring, truck and vehicle monitors at borders, safeguards measurements, cargo container monitoring, well borehole logging, monitoring of nuclear plant operations, waste management, and routine environmental monitoring.