Thermo Scientific DensityPRO NAI Series, User Manual

Page: 110 / 196

Operation
Application Screens
4
-
58 DensityPRO User Manual Thermo Scientific

Radioactive Source Activity (mCi)

Isotope Half Life (years)
3. The Detector Data Counts Hold Mode dropdown allows the user to operate in
Live mode or Hold mode. In the Hold mode, the user may enter a value in the
Detector Data Counts Hold Value textbox. In Live mode, the user does not have
this option.
4. The user has the option of entering values into the following textboxes:

Total Background Counts

Detector under range limit (cps)

Detector over range limit (cps)

Total Raw Data Count (cps)

Total Filtered Data Count (cps)
Standardization
Standardization is defined as a process that takes a radiation measurement for a
standard process configuration to establish a reference point for the gauge. This process
also ensures confidence in the accuracy of the calibration curve. The procedure requires
the measurement section to be either pipe empty or full. When full is selected, the pipe
should be filled with carrier or to be in some other repeatable condition.
The standardization measurement provides the gauge with a standard configuration
reference point. During the standardization cycle, the gauge averages the detector
signal. The default cycle time lasts about two minutes. This averaged detector signal
provides a repeatable measurement of the signal produced in the standard
configuration.
Once the standardization measurement is completed, it can be repeated later to
compensate for any changes, such as increased attenuation due to process material
buildup on the pipe walls. The gauge can then adjust the calibration values based on
the new standardization value. The calibration values are adjusted automatically
whenever a new standardization is performed. Thus, it is not necessary to repeat the
calibration measurements.
Using as a Default
Calibration Value
By default, the gauge uses carrier density as the calibration (CAL) point. For some
applications, this default CAL point may provide adequate measurement accuracy
without performing any additional calibration measurements. For example, if the
standardization is performed on a pipe full of clean carrier (for a slurry material type)
and solids concentration is selected as the primary measurement, the measurement
readout should be reasonably accurate.