Selective, high-energy beta scintillation sensor for real-time, in situ characterization of uranium-238 and strontium-90

A novel scintillating-fiber sensor for detecting high-energy beta particleshas been designed and built at the Pacific Northwest Laboratory to characterize238U and90Sr in surface soils. High-energy betas generate unique signals as they pass through multiple layers of scintillating fibers that make up the active region of the detector. Lower-energy beta particles, gamma rays, and cosmic-ray-generated particles comprise the majority of the background interferences. The resulting signals produced by these latter phenomena are effectively discriminated against due to the combination of the sensor's multi-layer configuration and its interlayer coincidence/anti- coincidencecircuitry.