Portable Tritium-in-Air-Monitor

Tyne Engineering’s new handheld Tritium In-Air Monitor monitors for both tritium and gamma in a single robust, portable instrument.

• Simple to use, with only one operating switch with four settings: Off, Sample, Pump, Set Up.

• Gamma Compensation with four large ion chambers arranged in a cruciform configuration. Two chambers are used for measuring the air sample, and two are for compensation.

• Less than 10% inaccuracy in 20 mR/hr field

• High Sensitivity. The volume of a measured charge is 500 cc. The current amplification circuit employs ultra-low leakage technology. Each chamber has its individual amplifier, increasing the Signal-Noise Ratio of the analog circuit.

• Sensitivity is 1µCi/m³.

• Radon compensation is provided by the analog filter circuit designed to separate the radon spike. The software can distinguish the radon spike from the tritium signal occuring as a slow-change signal.

• Ion-traps are built into each ion chamber.

• Noble gas compensation is accomplished by interposing a desiccant cartridge between the ports of the measurement and compensation chambers. The airflow to and from these chambers is channeled through ports that are accessible from the instrument's faceplate. The noble gas signal can be displayed by the micro-processor.

• Direct gamma measurement is provided using an installed GM tube.

• Decontamination by purging of all 4 ion chambers can be achieved with use of the centrally installed cartridge heater.

Compensation for Gamma background is crucial in tritium measurement, since a gamma field of 1mR/Hr will generate 500 times the ionization generated in 1µCi/m³ of tritium. Tyne designed the four, 250 cc ion –chambers in a cruciform with each chamber connected to an ultra sensitive electrometer amplifier and filter. All signals pass through the ADC converter, and the micro-processor calculates and displays the tritium value. To cover high ranges of tritium a separate small ion chamber is used. Measurements such as flow from the solid-state flowmeter and chamber temperature are also monitored by the micro-processor.

Instrument output includes analog (0-5V, 4-20mA); relay alarm contact (30VDC, 1A) for operation of external equipment; and communication (RS232/RS485) to enable downloading or recording of information onto a computer. The TFT full color LCD display mounted on the surface plate clearly displays instrument readings in both digital and graphic format to show real time measurements and trends.

The well balanced, easy-to-carry instrument can be placed on its end for easy visibility of the touch screen monitors to operators working away from the instrument.

Batteries installed in the handle are easily replaced.

A powerful long-life pump can be used to draw air through a 10 meter tube. This allows the instrument to be used to measure the inside of rooms without the need to enter the room.