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Physics-based, Bayesian sequential detection method and system for radioactive contraband

United States Patent

March 18, 2014
View the Complete Patent at the US Patent & Trademark Office
Lawrence Livermore National Laboratory - Visit the Industrial Partnerships Office Website
A distributed sequential method and system for detecting and identifying radioactive contraband from highly uncertain (noisy) low-count, radionuclide measurements, i.e. an event mode sequence (EMS), using a statistical approach based on Bayesian inference and physics-model-based signal processing based on the representation of a radionuclide as a monoenergetic decomposition of monoenergetic sources. For a given photon event of the EMS, the appropriate monoenergy processing channel is determined using a confidence interval condition-based discriminator for the energy amplitude and interarrival time and parameter estimates are used to update a measured probability density function estimate for a target radionuclide. A sequential likelihood ratio test is then used to determine one of two threshold conditions signifying that the EMS is either identified as the target radionuclide or not, and if not, then repeating the process for the next sequential photon event of the EMS until one of the two threshold conditions is satisfied.
Candy; James V. (Danville, CA), Axelrod; Michael C. (San Ramon, CA), Breitfeller; Eric F. (Dublin, CA), Chambers; David H. (Livermore, CA), Guidry; Brian L. (Livermore, CA), Manatt; Douglas R. (Livermore, CA), Meyer; Alan W. (Danville, CA), Sale; Kenneth E. (Castro Valley, CA)
Lawrence Livermore National Security, LLC (Livermore, CA)
12/ 259,198
October 27, 2008
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT The United States Government has rights in this invention pursuant to Contract No. DE-AC52-07NA27344 between the United States Department of Energy and Lawrence Livermore National Security, LLC for the operation of Lawrence Livermore National Laboratory.