PerkinElmer QuantaSmart 1694267, Reference Manual

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CHAPTER 10
186 PerkinElmer Life and Analytical Sciences
Radioactivity Units
The Curie and the Becquerel represent different units of measure for radioactivity.
The Becquerel is the International System (SI) unit of activity.
2 Sigma % (%2s)
This value represents the percent of uncertainty in a gross count value (with 95%
confidence limits). It is calculated as:
The following table indicates the total accumulated counts necessary to achieve
the corresponding 2% Sigma:
Figure 10-1 Gross Count Equivalents for 2 Sigma Percent Values
Becquerels 10 x 3.7 Curie One
(DPS) Second Per tion Disintegra One Becquerel One
10
=
=
counts d accumulate
200
%2s
=