Multi-Isotope determination of uranium-rich material using accelerator mass spectrometry

Environmental detection of trace isotopes 233U and 236U are important forensic signatures for identifying uranium ore materials or tracking anthropogenic releases from weapons fallout or nuclear reprocessing. Currently, Accelerator Mass Spectrometry (AMS) is the only method sensitive enough to detect signatures of 233U/U and 236U/U at the natural level due to the molecular interferences of 232ThH and 235UH, respectively, often present in conventional mass spectrometry. In this work, we detail the AMS capabilities of actinides developed at the University of Notre Dame's Nuclear Science Laboratory (NSL). For the first time in our laboratory, we have measured isotopic ratios of 236U/U and explored additional signatures of 233U and decay chain products 231Pa and 230Th in both natural ore material and two National Bureau of Standards samples. In this work we estimate a system sensitivity for 236U/U of 1.4 x 10-11 and characterize the simultaneous detection of 233U, 231Pa, and 230Th.