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