The Model FP400 is a “fast purge” version of the Model 400SBDyC. Includes four small 110cc ionization chambers and a faster pump (2-4 LPM) to provide a quicker response rate, requiring just 12-15 seconds to reach 90% of the final reading. The cruciform chamber geometry provides nearly perfect gamma compensation regardless of photon energy, flux gradient, or flux direction. Two ion chambers are used for measurement (220cc total) and two for gamma compensation (220cc total). Useful for applications which require low-level sensitivity and extremely fast and stable response. In comparison, the Model 400SBDyC utilizes four 200cc ionization chambers and a pump rated for 1.5 – 2 LPM.
Power is supplied by a pair of “D” size alkaline or NiMH rechargeable batteries. 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 FP400 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 FP400 includes proprietary radon recognition and elimination circuitry to provide accurate, fast, and drift-free measurement.
|MEASUREMENT RANGE||1 – 19,999 μCi/m3, basic sensitivity of the order of 5 μCi/m3|
Other available measurement ranges:
0.1 to 1,999.9 MBq/m3 or DAC
1 to 19,999 μSv/h
|DISPLAY||0 – 19,999 digits, LCD panel meter|
|ACCURACY, SPAN||±10 % of reading, ±5 μCi /m3, whichever is greater|
|NOISE LEVEL||± 5μCi/m3, 1 S.D. (5 second electronic time constant)|
|ZERO STABILITY||after 30 seconds (or less) warm up, zero drift less than ± 5μCi/m3|
|GAMMA COMPENSATION||multiple chambers arranged in a cruciform geometry reduces errors due to external gamma radiation; volume: 220cc|
|ALPHA PULSE SUPPRESSION||a circuit provides recognition and cancellation of undesirable noise spikes attributed to airborne radon|
|RESPONSE RATE||12-15 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
|EXTERNAL CONNECTIONS||Optional RS-232 Data output|
|IONIZATION CHAMBER VOLUME||effective measurement volume: 220 cm3|
port to port volume: 240 cm3
|DUST FILTER||HEPA, external in-line disposable cartridge type|
|PUMP||internal rotary vane pump|
|FLOW RATE||nominally 2-4 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 5.7″ [145mm] H excluding handle, 6.5 lbs (3 kg)|