The continuous monitoring of radon gas concentration is a useful method for studying the effects
of ventilation on radon concentration levels. The determination of average radon concentration is more
preferable than the active-type. For this purpose, a model chamber of cubic shape made of plexy-glass
Radon calibration chamber is a good tool for testing radon measurements for different devices and
techniques, a 0.65m3 plexy-glass chamber was constructed to compare between different detecting devices
with the change of environmental conditions (temperature–relative humidity–samples concentration) as
well as the use of devices inside or outside the chamber. This chamber resembles to a great extend the
mines atmosphere which helps in using it as a pilot plant.
For this purpose, two devices (RDA-200 and TRI-MET 372) are used for active-type. (RGM l/l and
CRM-1027) devices are used for continuous monitoring. The experiments are carried out at two different
environmental conditions, one by using high temperature (40oC) and relative humidity (100%), the other by
using low temperature (16oC) and low relative humidity (50%).
The obtained results show that, lower stability in the measurements with the change in environmental
conditions. More stability for the RDA - 200 and Tri-Met devices at high temperature and high humidity
was observed. From the other hand, a more stability for both RGM and CRM devices is clearly appeared
at low temperature and low humidity conditions. This may be attributed to that the measurements depend
mainly on an electronic circuit which has a higher performance at these environmental conditions.