BERTHOLD TECHNOLOGIES LB4710-050, User Manual

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Chapter 5 Explanations
Mini-Switch LB 471
59
b) Second best method
If the source has already been installed, the following prerequisites
should be met:

closed radiation exit channel

full container
c) Third best method
If the container cannot be filled above the monitoring level, then at
least the radiation exit channel has to be closed.
If this method is used, the detector often receives a minor amount
of residual radiation from the radiation source, which is negligible
for Cs-137 sources. For Co-60 sources this method may be used
only if the influence of the residual radiation on the measurement
can be estimated.
Figure 7:
Determining the zero count
rate at full container
Figure 8:
Determining the zero count
rate at empty container
closed radiation
exit channel
Empty container
closed radiation
exit channel
full container