| Photon activation analysis (PAA) was utilized to nondestructively detect and quantify
trace quantities of actinides for potential application in nuclear forensics and in industry. PAA
employs active interrogation techniques to provide a rapid sample assay without the need for
complete sample dissolution and/or chemical assays. PAA was applied to ore sam- ples
containing trace amounts of thorium and uranium with the aim of both determining the
minimum detectable mass of actinides in the sample as well as quantifying the concen- trations
of thorium and uranium through the development of an analysis technique that can be
deployed to rapidly characterize such samples. The differing photofission product yields of
uranium and thorium allow the quantification of the trace amounts of these actinides in
the uranium reference ore samples. By utilizing the differences in the fission fragment yields
of fission daughter products, the gamma peaks produced through the deexcitation of key
daughter products can be fit and analyzed to calculate the concentration of actinides in
radioactive samples. A method to determine the amounts of trace actinides in soil samples is
presented as well as improvements that need to be made to reduce the errors inherent in this
method.
Key Words: Photon Activation Analysis, Reference Ore, Photofission, Bremsstrahlung, Min-
imum Detectable Mass, Concentration Calculation |