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Model 3030P Technical Manual
Section 7
Ludlum Measurements, Inc. Page 36 February 2021
Background QC Count Time (min):
the background count time in minutes
used when the Override Count Time function is enabled
Alpha/Beta Upper & Lower Limits
: These determine what range is
acceptable for the background during a QC check. If the background does
not fall within these values, the QC check will fail.
STEPS FOR PERFORMING A QC CHECK
1. To enable the QC mode, click on the box marked “Normal QC” in
the tab marked “QC Settings.”
2. Press the button marked “Reload Last Values” at the top of the
screen to see the last values calculated during the last QC check.
The data shown includes the Last QC Performed, the Last Alpha
Efficiency, the Last Beta Efficiency, the Last Alpha Background,
and the Last Beta Background. These numbers are shown for
reference ONLY. The QC-check predetermined limits must be
chosen and input by the user.
3. Enter values for the Standard Alpha Efficiency and the Standard
Beta Efficiency. The values input here should reflect the average
efficiency with the given sources. After entering the values, press the
Update button.
4. Enter values for the Allowable QC Efficiency. These percentage
values entered allow the instrument to accept efficiencies that are
somewhat higher and lower than the standard efficiency. For
example, if the Standard Alpha Efficiency is 25% and the Allowable
QC Efficiency is 5%, the acceptable alpha efficiency will be from
20% to 30%. After entering the values, press the Update button.
5. Enter the Alpha Source Activity and Beta Source Activity of the
sources to be used during the QC check. It is preferred to use the
DPM or µCi column wherever possible. Conversion from CPM to
DPM using a factor of 2 may not be correct, depending on isotope
and source material. After entering the values, press the Update
button.
Enter in upper and lower background limits for both alpha and beta
background. Since alpha background is usually very low, it is acceptable to
use a lower limit of 0. After entering the values, press the Update button.