• The Ludlum Model 333-2 Beta Air Monitor together with the optional Model 333-1P Regulated Vacuum Pump form a complete air monitoring system. The Model 333-2 is configured for continuous sampling of airborne beta-emitters. The detection system consists of a primary pancake detector facing the upstream side of the filter paper and a second gamma subtract pancake detector located behind and facing the back of the Primary Detector. The sampling assembly is surrounded by 2 inches of lead shielding. The Model 333-2 has dual alarm setpoints that provide independent setting of the ALERT level (strobe) and the ALARM level (bell). Setpoints may be checked via the front panel pushbuttons; however, the adjustments controls are located behind the calibration cover plate. Failure detection is provided for loss of count in the primary detector. Contact closure is provided for all three of the alarm annunciations listed above. Two recorder outputs are provided. A Lo/No air flow indicator flashes.

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