Berthold LB 134, Руководство пользователя

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LB 134 Design and Mode of Operation of the LB134
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1.3 Nuclides and Measurement Types
A separate calibration factor is needed for each nuclide to de-
termine alpha, beta or gamma contamination. We distinguish
between alpha and beta/gamma nuclides and assign a calibra-
tion factor to each nuclide. Betas and gammas are essentially
measured in the same measuring channel and cannot be dis-
tinguished alone with the detector. Since there are two different
definitions for the calibration of the detectors, according to the
DIN 25415 and DIN ISO 7503 standards, we need two calibra-
tion factors for each nuclide. The nuclide tables of the contami-
nation probes contain about 70 nuclides with the following en-
tries for each nuclide: Name, DIN and ISO calibration factor,
alarm threshold, type of radiation (α, β, γ or n), unit, integral
threshold, integral unit, time base for integration and status in-
dication whether it is enabled. Before each measurement, you
have to select the desired alpha and beta nuclide so that the
correct settings are selected. DIN or ISO standard are deter-
mined on initial setup of the device by the supervisor and set in
the system parameters, and is then usually not changed any
more. Nuclides can be deleted or entered new or their parame-
ters can be changed.
When using a gamma or neutron doserate probe, for example,
no nuclide data are needed because these probes are energy
independent and, therefore, nuclide independent in the defined
measuring range. You do not have to select a nuclide prior to
the measurement. Instead of a nuclide selection, the LB 134 in-
cludes a "measuring type" selection for these and similar
probes. Each measuring type also has, very similar to the pa-
rameters of a nuclide, a parameter set with almost the same en-
tries; however, there is only one calibration factor. This can be
used, for example, to define one of the following measurement
types:

Dose rate 1:
With calibration factor for ambient dose equivalent rate
H*(10), unit µSv/h, thresholds as desired

Dose rate 2:
With calibration factor for ambient dose equivalent rate
H*(10), unit mrem/h, thresholds as desired (USA)

etc.
Of course, the correct calibration factors must be entered for
the parameters of the individual measurement types. Using this
method, one can very quickly change, similar to the nuclides,
the measurement types to adapt to the requirements of other
countries.