Strontium-90 and Plutonium Analyses To measure 9°Sr content, °°Y was chemically separated from °° Sr, collected Plutonium was extracted by ion exchange, electroplated on platinum discs, and analyzed by alpha spectrometry with systems using Surface barrier alpha detectors and pulse-height analyzers. Chemical yield was determined by use of 2**Pu as a ee ene tracer. Error Limits For a single sample, the erro given for ail radionuclides listed are two-sigma, propagated, counting errors. The error term for more than one sample is one standard deviation and disregards counting error. Limits of Detection Many factors influence the limit of detection, including the type of detector and analyzer, the presence of other radionuclides, the duration of the counting period, the size and density of the sample, and the geometry relationship of the sample and detector. Hence, the limits of detection varied considerably for various radionuclides and types of samptes, but can be summarized by stating that the detection limits were approximately as follows: By gamma detection “eK 2.1 pCi/g or less 238y 0.41 ®°Co, 145Sb, 137Cs, P5S5Eu, 244 Am 0.12 pCi/g or less By beta detection 9°Sy By alpha detection 239,240py pneee ee on a filter paper and counted with a low-level beta counting system. ny a 0.2 pCi/g or less 0.02 pCi/g or less