The IRGprobe system consists of the radon gas probe and a case with power supply, sampling pump, printer, keyboard and optional battery. The microcomputer of the intelligent probe controls the measurement, evaluates the data and prints directly the results.
For measurements in the soil a hand operated drilling tool and an set of stainless steel tubes can be ordered. A hole is drilled into the ground, a stainless steel tube is inserted, and the probe is shifted into the tube. The top of the tube is closed, and the space between tube and the wall of the bore-hole must be sealed with filling material. If the soil is too wet the probe can be pulled up, to protect the detector from water.
The probe of the IRGprobe system is a self contained instrument with all elements of an intelligent data collection system and an alpha-spetrometer including:
The figure shows a cross section of the cylindrical probe. The radon gas enters the decay chamber via the inlet filter. In the passive mode the radon enters by diffusion. In the active mode the gas is sucked in by the pump of the supply case which is also controlled by the micro computer.
The radon in the
chamber decays into its daughters which deposit at the walls of the chamber and
at the detector surface. The integrated multichannel analyser collects continuously
the alpha-spectrum of the deposited activity. The micro-computer analyses the spectrum
and calculates the gas activity from the collected
In the active mode the micro computer increases the air flow rate in predefined steps and prints or plots the activity concentration as a function of the flow rate. This function is one information which is needed to predict the radon concentration in a hypothetical house at the given location.
The IRGprobe uses the double filter method with an inlet filter, a decay chamber, and a second filter which collects the progeny, growing in the chamber. The inlet filter is a mechanical filter. The deposition of the progeny by diffusion acts as the second filter. The air sampling is done by diffusion or by a variable air flow.