The AM2M is a continuous air monitoring system designed to measure the particulate and noble gas activity in a sample airstream. The AM2M uses two separate measuring channels arranged in series to perform the measurement. A common vacuum pumping system is used for transport of the sample gases through the system. Local RM1W display and control units are included for system operation, data concentration and communication. The particulate channel uses a lead shielded moving filter providing collection of airborne particles using a continuous spool of filter paper. The filter paper deposition is designed to provide an even distribution and includes the capability of adjusting the filter paper speed to accommodate applications that deposit higher activities, such as post-accident monitoring and analysis. The particulate channel will be equipped with a beta sensitive plastic scintillation detector (model SD201PB) for detection of beta emitting particles. The detector interfaces with a locally mounted pulse analyzer (model SDA3E) which provides the biasing voltage to the detector, analyzes the nuclear pulses for counting, and provides an automatic gain control function.

The SDA3E unit communicates with the skid mounted display and control unit (model RM1W) using Ethernet (TCP/IP), RS232 or RS485 communications for display of the measured activity and for alarm determination. The exhaust from the particulate channel is plumbed to the inlet of the noble gas monitoring channel. The sample gases, with particulate and iodine activity removed, enter the noble gas sampler for measurement. The noble gas sampler (model GS54) is a lead shielded sampler enclosing a sensitive volume. A SD201PB beta scintillation detector is located with the sensitive volume for measurement of noble gas activity. Again, the detector detects the nuclear events, pulses, biasing voltage, and performs gain stabilization. The noble gas sampler includes a vacuum transducer to automatically correct the measured activity to standard pressure. The vacuum pumping system uses a positive displacement carbon vane pump for transport of sample gases through the monitoring system. A mass flow meter and proportional control valve allows the sample flow rate to be either manual set to the desired flow or to match the sample flow rate to a stack or vent velocity for representative sampling. The flow rate is provided to the local RM1W electronics for determination of total release and for calculation of concentrations. Alarms are included for annunciation of a low flow condition.