A small, lightweight and portable tritium air monitor
The Model 400AC is a compact and lightweight portable tritium in air monitor with several advanced features, including a gamma compensation on/off toggle switch for straightforward gamma calibration, NiMH rechargeable batteries, RS-232 data output, and automatic calibration software.
With four 200cc ion chambers arranged in a cruciform geometry, the Model 400AC can ensure nearly perfect gamma compensation regardless of photon energy, flux gradient, or flux direction.
Rechargeable battery and adjustable alarm thresholds
Powered by two “D” size NiMH rechargeable batteries, an LED indicator shows the onset of battery depletion. This LED will also turn red to signal a malfunction with the high voltage power supply.
The front panel features a nine-position alarm level stepped attenuator, which can be adjusted over a range of 2 to 1,000 µCi/m3. If the measurement exceeds the alarm set-point, a steady tone is emitted and the red LED illuminates. Similarly, if the sample airflow is interrupted, the yellow LED lights up and the steady tone sounds.
Drift-free with high sensitivity
Zero adjustment is unnecessary as the electrometer is temperature stable and exhibits zero drift from 0°C to 50°C. This stability is achieved through the careful selection of an ultra-high impedance semiconductor with low internal current leakage and long-term DC stability.
The 400AC can reliably measure currents as low as 10-16 A, with permanently stable span calibration. The ionisation chamber polarising voltage is provided by an electronically regulated, low-noise dual high-voltage power supply (±80VDC). Additionally, the 400AC features proprietary radon recognition and elimination circuitry for accurate, fast, and drift-free measurements.
Key Features
- High performance portable tritium air monitor with upgraded features
- Gamma compensation ON/OFF toggle switch for easy gamma source calibration
- Automatic recalibration software
- Cruciform gamma compensation (400cc volume) with virtually no offset in fields up to 10 mR/h
- Sensitivity: 2 µCi/m3, 0.1 MBq/m3
- Range: 1 to 19,999 µCi/m3 or 0.1 to 1,999.9 MBq/m3 (µSv/h also available)
- Audible and visual alarm indicators for low flow, low battery, and signal level
- High voltage power supply malfunction alarm
- Alpha pulse suppression, radon rejection
- RS-232 Data Output
- No long-term drift, no manual zero adjustments
- Offset potentiometer control included
- CE Marked
Technical Specifications
Measurement Range | 1 – 19,999 µCi/m3 Other available measurement ranges:
|
Sensitvity | 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 | RS232 serial data output for tritium measurement, level alarm status and calibration |
Ionisation chamber volume | Effective volume: 400 cm3 port to port volume: 440 cm3 |
Dust filter | External in-line disposable cartridge type |
Pump | Internal rotary vane pump, flow rate: nominally 1.5 – 2 LPM |
Environmental | 0° C to +40° C, 20 – 90 % relative humidity non-condensing |
Batteries | Two “D” size NiMH 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) |
Calibration | Automatic Calibration using pc-based software (included) Manual Calibration by adjusting a calibration potentiometer |
Accessories included | • 2 “D” Size NiMH Batteries • 2.3 meter DB9 cable for RS-232 serial data output • Sniffer hose • Dust filter • AC Power converter • Carrying case (optional) |
Documents
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Model-400AC-Brochure
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