The Model 347 is an ultra-sensitive stationary tritium in air monitor designed for continuous duty. The 347 utilizes four 2L ionization chambers for the best possible sensitivity, stability, and gamma compensation available. The large chamber volume provides additional sensitivity and stability, even in areas with elevated or fluctuating background levels. Two chambers are used for measurement and two for gamma compensation, arranged in a cruciform geometry to provide near perfect gamma compensation regardless of photon energy, flux gradient, or flux direction. The pump system is mounted on a separate panel and includes an ultra-pure filter element, HEPA filter, pump, and flowmeter. The ultra-pure filter element combined with the HEPA filter ensure the sample air is completely clean of particulates before being measured to enhance the sensitivity and accuracy. With radon rejection, the Model 347 is fast, ultra-sensitive, and accurate.
The Model 347 includes a standard 0-10VDC analog output found on all our stationary instruments and can support one additional data output (choice of: RS-232, RS-485, 4-20mA, or Ethernet). It has a simple alarm system consisting of a single independent signal alarm and a toggle switch with three alarm modes: on, off, and reset. The signal alarm activates the acoustic signal and will continue to operate until manually reset, even if the displayed signal has receded below the setpoint. A remote alarm unit can be added that includes a latching or timing circuit to easily mute and re-set the alarm. Relay interface connections are included on a terminal block at the rear of the enclosure.
Proprietary circuitry provides recognition and cancellation of undesirable noise spikes attributed to airborne radon. Unique plate-out proof wire-grid ion chambers are available in place of the standard solid-wall chambers which will reduce tritium contamination by three orders of magnitude by decreasing the true surface area of the chamber.
The only maintenance required for the 347 is periodic service of the pump and replacement of the dust filter. The sensitivity, accuracy, and noise level of the Model 347 is superior to competitive instrumentation by an order of magnitude.
Calibration of the 347 tritium monitor can be accomplished by three different methods:
|RANGES||Available in the following ranges:|
a) 1 to 19,999 μCi/m3, MDA is 0.5 μCi/m3
b) 0.1 to 1,999.9 μCi/m3, MDA is 0.5 μCi/m3
c) 0.01 to 199.99 MBq/m3, MDA is 0.02 MBq/m3
|DISPLAY||4 ½ digit panel meter|
|ACCURACY||±10 % of reading, 1 µCi/m3 whichever is greater|
|STABILITY AND DRIFT, LONG TERM||±0.5 µCi/m3, ambient temperature, after warm-up|
|NOISE||<1 µCi/m3, 1 sigma, with 20 second time constant|
|GAMMA COMPENSATION||second pair of ionization chambers of equal volume, mounted in cruciform pattern, serves to cancel effects of external gamma fields, total compensation volume: 4,000 cm3|
|RESPONSE RATE ELECTRONIC||two linear time constants, 30 seconds for <80 µCi/m3|
3 seconds for >80 µCi/m3
|WARM-UP TIME||less than 5 minutes required for high voltage power supplies to stabilize|
|ALARM SYSTEM||single alarm, with set point adjustable from 1 to 1000 µCi/m3|
|IONIZATION CHAMBER MEASUREMENT VOLUME||measuring: 2900 cm3|
total wetted: 4000 cm3
|ENVIRONMENTAL||storage: -40° C to +60° C|
operating: 0° C to +50° C
0 to 95 % R.H. non-condensing
|FLOWMETER||0 -10 LPM adjustable rotameter|
|DIMENSIONS||8.8” [223mm] H x 19.0” [483mm] W x 16.0” [406mm] D|
|WEIGHT||45 lbs [20.4 kg]|
|POWER||115 VAC or 240 VAC 50/60 Hz|
|DUST FILTER, FLOW METER, and PUMP separately mounted|
|DIMENSIONS||7.0” [178mm] H x 17.0” [432mm] W x 16.0” [406mm] D|
|WEIGHT||20 lbs [9.1 kg]|
|OPTIONS||Choice of one data output:|
-RS232, USB, Ethernet, 4-20mA, or logarithmic Output
-Stainless Steel Wheeled Cart