Ludlum Measurements 334A, Руководство по эксплуатации

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Model 334A Operations Manual
Ludlum Measurements, Inc 9 January 2021
Calibration
To maintain accurate measurements of dose and concentration, the unit must be calibrated
periodically. Separate Alpha and Flow calibrations are required for complete calibration.
The purpose of alpha calibration is to insure that the peak-fitting algorithm knows where in the
spectrum to expect the radon peaks. This ensures that proper radon background subtraction is
performed. If the radon peaks appear too far from the expected locations, the peak-fitting
algorithm will fail (POOR FIT status) and the unit will fail to alarm properly.
Flow calibration is important, as it determines if the Model 334A is converting the pump current
into the measured flow rate correctly.
The calibration functions are accessed from the Calibration item on the main menu. Two types
of calibrations can be performed on the Model 334A. The first is called the “Automatic Alpha”
calibration, which is a source calibration check. The other type of calibration is the “Advanced”
calibration, which separates Alpha Energy and Alpha Efficiency calibrations. Advanced
Calibrations should be performed in this order: Alpha Energy

Alpha Efficiency

Flow
NOTE: Ludlum instruments are shipped already calibrated at the factory elevation of
5100 feet. Because they are elevation-dependent, both the Advanced Alpha Energy
Calibration and Flow Calibration should be repeated at the customer site, for elevation
differences of greater than 1000 feet, before the instrument is put into service.
For new instruments, the customer should perform the “advanced” alpha energy and efficiency
calibrations so that subsequent Automatic Alpha calibrations start from an accurate calibration
baseline.
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