The Model 400SBDyC is a high-performance lightweight portable tritium in air monitor and the basis of the 400 series. All models in the 400 series include four 200cc ion chambers arranged in a cruciform geometry which provides nearly perfect gamma compensation regardless of photon energy, flux gradient, or flux direction. Two ion chambers are used for measurement (400cc total) and two for gamma compensation (400cc total). The Model 400SBDyC has a fast response time of less than 30 seconds and can accurately detect tritium down to a sensitivity of 2 µCi/m3 or 0.1 MBq/m3.
Power is supplied by a pair of “D” size batteries in your choice of alkaline or NiMH rechargeable. Onset of the battery depletion is signaled by illumination of an LED located next to the meter face. This same LED will also signal red when there is a malfunction with the high voltage power supply. A nine-position alarm level stepped attenuator, adjustable over partial scale (2 to 1,000 µCi/m3) is located on the front panel. A steady tone is emitted by an acoustic signaler if the measurement exceeds the alarm set-point (illuminates red LED), or if the sample airflow has been interrupted and is too low (illuminates yellow LED). The alarms are non-latching.
Zero adjustment is unnecessary, the electrometer is completely temperature stable and shows zero drift from 0° C to 50° C due to special design and careful selection of an ultra-high impedance semiconductor with low internal current leakage and long-term DC stability. The 400SBDyC can reliably measure currents as low as 10-16 amperes and the span calibration is permanently stable. The ionization chamber polarizing voltage is supplied by an electronic low-noise regulated dual high-voltage power supply (±80VDC). The 400SBDyC includes proprietary radon recognition and elimination circuitry to provide accurate, fast, and drift-free measurement.
The Model RS400 is the same as the Model 400SBDyC but includes RS-232 data output.
|MEASUREMENT RANGE||1 – 19,999 µCi/m3|
Other available measurement ranges:
0.1 to 1,999.9 MBq/m3 or DAC
1 to 19,999 µSv/h
|SENSITIVITY||2 µCi/m3 (0.1 MBq/m3)|
|DISPLAY||0 – 19,999 digits, LCD panel meter|
|ACCURACY, SPAN||±10 % of reading, ±2 µCi /m3, whichever is greater|
|NOISE LEVEL||± 1μCi/m3, 1 S.D. (10 second electronic time constant)|
|ZERO STABILITY||after 30 seconds (or less) warm up, zero drift less than ± 1μCi/m3|
|GAMMA COMPENSATION||chambers in a side by side pattern reduce errors due to external gamma radiation.|
|ALPHA PULSE SUPPRESSION||a circuit provides recognition and cancellation of undesirable noise spikes attributed to airborne radon|
|RESPONSE RATE||30 seconds to reach 90% of final reading|
|ALARM (ACOUSTIC)||1. Ten position stepped attenuator set point for signal alarm|
2 – 1,000 µCi/m3, steady tone. OFF position is included.
2. Low flow produces an intermittent tone
3. Mute switch silences audible tone
|ALARM (VISUAL)||signal level: red LED|
low flow: yellow LED, flashing
low battery: red LED
HVPS: red LED illuminates to indicate a malfunction with the high voltage power supply (HVPS) used to bias the ionization chambers
|EXTERNAL CONNECTIONS||Not Included. Data output (RS-232) only available on the following models: RS400, 400AC.|
|IONIZATION CHAMBER VOLUME||effective volume: 400 cm3|
port to port volume: 440 cm3
|DUST FILTER||HEPA, external in-line disposable cartridge type|
|PUMP||internal rotary vane pump|
|FLOW RATE||nominally 1.5 – 2 LPM|
|ENVIRONMENTAL||0° C to +40° C, 10 – 95 % relative humidity non-condensing|
|BATTERIES||two “D” size NiMH or Alkaline batteries|
external jack for supplementary power input and charging
|POWER CONVERTER||100-240 VAC, 50/60 Hz, .25 A to 3.3 Vdc @ 1.2 A|
5.5 mm O.D. x 2.1 mm I.D. Plug, center pin is positive
|SIZE AND WEIGHT||7.6″ [193mm] L x 5.2″ [132mm] W x 6.9″ [175mm] H excluding handle, 6.5 lbs (3 kg)|
|ACCESSORIES INCLUDED||• 2 “D” Size NiMH or Alkaline Batteries|
• Sniffer Hose
• Dust Filter
• AC Power Converter
• Optional– Carrying Case