The Model 200SB-HTO is a low-cost, lightweight, portable tritium in air monitor designed to measure tritium oxide (HTO) only, even in the presence of other radioactive gases such as noble gases, as well as background gamma. A rapid warmup, high-volume rotary vane pump, and fast electronics combine to give this tritium monitor a very quick overall response. Meter readings will reach 90% of the final value within just 5 seconds to a step response of aspirated tritium. The Model 200SB-HTO uses two coaxial 200cc ionization chambers, one for measurement and one for gamma compensation. A desiccant column is interposed between the measurement and compensation chambers to provide a differential measurement proportional to HTO only. The 200SB-HTO is our economy model, with medium sensitivity, a wide range, and fast response.
Power is supplied by a pair of “D” size alkaline batteries. Onset of the battery depletion is signaled by illumination of an LED located next to the meter face. A nine-position alarm level stepped attenuator, adjustable over partial scale (.01 – 5%) 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 200SB-HTO 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 a long-life electronic low-noise regulated dual high-voltage power supply (±80VDC). The 200SB-HTO includes proprietary radon recognition and elimination circuitry to provide accurate, fast, and drift-free measurement.
The Model 200SB-HTO includes 6 hose connections which can be adjusted for two operating modes to measure either:
For HTO measurement, an external desiccant column is interposed between the measurement and compensation chambers which absorbs and removes the HTO to provide a differential measurement that is proportional to HTO only [HTO + other radionuclide – (other radionuclide) = HTO].
|MEASUREMENT RANGE||10 – 199,999 µCi/m3|
Other available measurement ranges:
0.1 to 1,999.9 MBq/m3
1 to 19,999 DAC or MPCa
|SENSITIVITY||10 µCi/m3 (0.4 MBq/m3 or 1 MPca)|
|DISPLAY||LCD panel meter|
|ACCURACY, SPAN||±10 % of reading, ±10 µCi /m3, whichever is greater|
|NOISE LEVEL||± 10 μCi/m3, 1 S.D. (3 second electronic time constant)|
|ZERO STABILITY||after 1 minute (or less) warm up, zero drift less than ± 10 μCi/m3|
|GAMMA COMPENSATION||chambers in a side by side pattern reduce errors due to external gamma radiation.|
|RESPONSE RATE||5 seconds to reach 90% of final reading|
|ALARM (ACOUSTIC)||Nine position stepped attenuator set point for signal alarm
20 – 10,000 µCi/m3, steady tone.
Low flow produces a steady tone
|ALARM (VISUAL)||signal level: red LED|
low flow: yellow LED
low battery: red LED
|EXTERNAL CONNECTIONS||not available|
|IONIZATION CHAMBER VOLUME||effective volume: 200 cm3|
port to port volume: 220 cm3
|DUST FILTER||external in-line disposable cartridge type P/N 12082|
|SAMPLING SYSTEM||6 hose barb ports are located on the front panel for measuring either Total Tritium or HTO only|
|PUMP||special high volume internal rotary vane pump|
|FLOW RATE||nominally 2-3 LPM|
|ENVIRONMENTAL||0° C to +50° C, 0 – 95 % relative humidity non-condensing|
|BATTERIES||two “D” size batteries, alkaline|
|SIZE||7.6″ L, 5.2″ W, 4.4″ H excluding handle|
|WEIGHT||5 lbs (2.3 kg)|
|Accessories included:||• 2 “D” Size Alkaline batteries|
• Sniffer hose
• Dust filter
• Two desiccant cartridges (filled with desiccant) for HTO only measurement
• AC Power converter (optional)
• Carrying case (optional)