Metrological Operations - ECOTEST VIRTUOSO RKG-14 Operating Manual

2.10 Metrological operations

The mode of metrological operations is used in cases where it is necessary
to make sure that the device preserves metrological characteristics in the most
responsible type of measurement - namely, in the measurements of specific
activity.
This mode is also used when it is necessary to compare the device
measurement results with those of other measuring instruments, especially
laboratory spectrometers-radiometers.
This mode is recommended only in specific cases and only to experienced
professionals who know the rules and how to select conditions, geometry and
measurement modes.
The "Metrological operations" measurement mode can be accessed by
tapping "TEST" button in the mode of gamma dose rate measurement (see
Fig. 2.4). Select either "Cs" or "K, Ra, Th" tabs and touch the "Metrological
operations" icon.
Since metrological samples are typically located in the Marinelli vessels,
this mode is designed for such measurement geometry.
The detector should be put on the top surface of Marinelli vessel.
Figure 2.68 – Detector on the top of Marinelli vessel
If the comparative measurements are performed in the laboratory, where
there is a lead shield, the metrological vessel with the detector can also be placed in
the shield. However, it is possible to carry out this measurement without additional
shield after checking natural background level at the point of measurement (it
should not exceed 0.15 mSv/h) and the absence of outside (background) radiation.
In the event of a similar test for measurement of specific activity of naturally
occurring radioactive materials the background radiation component should be
properly considered (especially with low-level metrology samples). Only an expert
familiar with the method of background radiation compensation can do that.
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