PerkinElmer QuantaSmart 1694267, Reference Manual

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CHAPTER 7
124 PerkinElmer Life and Analytical Sciences
Following is a brief description of the IPA Definition fields.
3H (Tritium) Standard DPM
Enter the DPM value for the unquenched, sealed Tritium standard (supplied). The
DPM values for standards purchased from PerkinElmer Life and Analytical Sciences
are printed on the vial.
3H (Tritium) Reference Date
Enter the reference (calibration) date for the unquenched Tritium standard. This is
the date on which the standard has the specified amount of activity. You must
enter this value for half-life correction to occur. The reference date for standards
purchased from PerkinElmer Life and Analytical Sciences are printed on the vial.
Carbon-14 Standard DPM
Enter the DPM value for the unquenched, sealed Carbon-14 standard (supplied).
The DPM values for standards purchased from PerkinElmer Life and Analytical
Sciences are printed on the vial. No reference date is required due to the long
half-life of Carbon-14.
Background Count Time
This is the length of time (in minutes) the instrument will measure the
background counts. The background for both Carbon-14 and Tritium are collected
simultaneously. Typically, a 60 minute count time is used to assess background.
Tritium Figure of Merit Threshold
This is the lower limit for the calculated Tritium Figure of Merit value. If the figure
of merit value falls below the defined threshold, a message is displayed in the
main window. If this occurs, it indicates either an increase in background or a
decrease in efficiency. Typically, the default threshold can be used until sufficient
IPA data for this parameter is collected and an alternate threshold is established.
Carbon-14 Figure of Merit Threshold
This is the lower limit for the calculated Carbon-14 Figure of Merit value. If the
figure of merit value falls below the defined threshold, a message is displayed in
the main window. If this occurs, it indicates either an increase in background or a
decrease in efficiency. Typically, the default threshold can be used until sufficient
IPA data for this parameter is collected and an alternate threshold is established.
Do Chi-Square Test for Tritium?
Mark this box to enable a test that measures the degree of reproducibility for
sample counting for Tritium. If the Chi-Square value for a Tritium standard
counted 20 times falls within an acceptable range of values, the variation in
individual sample counts is a result of the count statistics of the sample, as
opposed to an instrument problem.