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 b attery 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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