PerkinElmer QuantaSmart 1694267, Reference Manual

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ADVANCED FEATURES
PerkinElmer Life and Analytical Sciences 159
Alpha Beta Counting
Alpha Beta Discrimination is an optional feature on TriCarb Liquid scintillation
analyzers that provides the ability to discriminate between the gross alpha and
gross beta activity in a mixed sample. Results are reported as CPM alpha (CPMa)
and CPM beta (CPMA and CPMB).
In liquid scintillation counting, emission energies for alpha and higher energy beta
radionuclides such as
90
Sr/
90
Y will overlap, making discrimination between the
nuclides impossible on the basis of energy discrimination. However, alpha induced
pulses in a scintillation cocktail have a longer duration than beta induced pulses.
Pulse shape and duration are used to effectively discriminate between alpha and
beta activity.
TriCarbs equipped with the alpha/beta discrimination use Pulse Decay Analysis
(PDA), a form of pulse shape analysis, to perform the separation of alpha and
beta events. PDA uses a time based Pulse Decay Discriminator (PDD) to evaluate
the pulse duration of scintillation events and categorize the events as either alpha
or beta. Resolution of individual alpha or individual beta radionuclides is not
performed.