Ludlum Measurements 334A, Руководство по эксплуатации

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Model 334A Operations Manual
Ludlum Measurements, Inc 13 January 2021
Performing the Calibration
Alpha energy calibration consists of aligning the peak markers with the corresponding
isotope peaks in the spectrum. This is most efficient when a mid-energy (e.g. 5 MeV) source
is verified to appear near channel 120, then resetting the spectrum and accumulating a radon
spectrum overnight. Once the spectrum is positioned, the peak markers may be aligned.
Observe the following steps for more detail.
Consideration for Radon Mode
The Model 334A can be operated in “Radon Mode” where the radon/thoron progeny are
used to determine the PAEC (potential alpha energy concentration) exposure to the worker
in milli-working levels (mWL). There will be no marker for the PAEC channel. The PAEC
reading will replace the first isotope-of-interest, but a second IoI can be enabled, usually
Mixed Uranium, which will have a marker. In radon mode, a peak marker will also appear
for Po210. The energy of the Po210 peak is at 5.3 MeV, left of the Po218 peak.
Roughing in the Source Peak
If any of the configuration settings are drastically changed, it helps to perform this step to
reset them and get the radon peaks to appear in the correct location.
Place a mid-energy alpha source such as Am-241 in the sampling head and verify that the
peak appears just below mid spectrum (near channel 120) and that the peak tail narrows to
near zero at the left end of the spectrum. Adjust the Offset if needed, tapping reset
spectrum after each adjustment. This insures that the three radon progeny peaks should be
visible after the overnight run.
Collecting an Alpha Radon Spectrum
Reset the spectrum, and then make sure a clean filter has been inserted into the detector
head and leave the Alpha Energy Calibration window open on the screen before leaving the
Model 334A to collect the radon spectrum. Leave the Model 334A operating in a high
radon area for 8-12 hours so that a well-defined radon spectrum can be accumulated.