Model TASC-HT-HTO

Features:

  • Ultra-reliable tritium air sampler
  • Includes mass flow air control for consistent, precise sampling
  • Collects both HT and HTO with cascaded vials to ensure virtually 100% collection efficiency
  • Thermal oxidizer with a temperature indicator to convert HT to HTO, regulated range 455 – 475 °C
  • Standard flow rate sensitivity for 3H: 10-9 µCi/ml (10-9 Ci/m3) for 7-day period at 100 ml/min
  • High flow rate sensitivity for 3H: 10-9 µCi/ml (10-9 Ci/m3) for 24-hour period at 1 L/min

Description:

The Model TASC-HT-HTO is a high-quality and reliable passive tritium in air sampler.  Airborne tritium in the sample stream is continuously collected in vials filled with a liquid collection medium (water or glyocol).  The amount trapped increases linearly with elapsed time.  At regular intervals, the sampling is stopped, the contents removed and assayed using liquid scintillation counting to determine the amount of radioactivity collected.  Knowing the collection flow rate and the results of the scintillation assay, the average sample activity can be calculated for the period of time over which the sample was collected.   Passive samplers, although they do not provide real-time data, provide a low-cost and highly effective method of measuring extremely low levels for ensuring compliance with local regulations.

The TASC-HT-HTO is carefully designed and engineered so that it is easy to use, reliable, and consistent.  It has been in service for over 23 years, and many of the original units are still working to this day which is a testament to its reliability.  The sample holder tubing is made of 304/316 stainless steel which is cut, bent into shape, and brazed directly into sample holder caps which hold the sample collection bottles.  The whole assembly is leak tested, sandblasted for a uniform finish free of burs and oxidation, and finally electroplated for a bright nickel finish.

The TASC-HT-HTO collects both elemental tritium (HT) and tritium oxide (HTO).  First, the sample air is filtered by a high efficiency HEPA filter (99.99% at 0.1 microns) to remove dust and other particulates.  Next, HTO is directly trapped in the first set of vials, while the HT fraction of airborne tritium is trapped in the second set of vials by converting HT into HTO by means of a tube furnace.  Cascaded sets of vials are used to ensure virtually 100% sample collection.

A highly reliable mass flow meter precisely controls the flow rate through the sampler at a consistent value.  On the standard flow version, the mass flow rate is adjusted at the factory to 100 3 scc/min, and is set by a potentiometer on the flow controller circuit board.  The high flow version includes a front panel potentiometer to easily adjust the flow rate from 300 to 1,000 scc/min.

The front panel of the instrument has digital displays for flow rate, elapsed time, tube furnace temperature, as well as a visual indicator for low sample flow.  The high flow version also includes a digital display for totalized flow (flow rate x elapsed time).

Available in two versions:

Standard flow rate: 100 scc/min, with choice of 6x20mL collection vials or 4x60mL collection vials

High flow rate: 300 to 1,000 scc/min, flow rate adjustable via front panel potentiometer, with 4x250mL collection vials, includes totalized flow display

 

 

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