A simple radon chamber for use with soil gas for calibration of radon measuring devices and instruments

A simple and easy to use radon calibration chamber of volume of 216 litres was designed and constructed for applications in calibration of radon measuring devices and for research studies. The main advantage of this chamber is that instead of using 226 Ra source to generate the 222 Rn inside the chamber, soil gas is utilised as a source of 222 Rn. Soil gas is drawn from the soil using a pump to fill the chamber in order to obtain radon with high concentrations inside the chamber. The advantage of this technique is that the desired radon concentration (ranging from few Bq/m 3 to about kBq/m 3 ) can be attained easily and fast at any time by filling the chamber with different volumes of soil gas. After demonstrating the usefulness of the technique, calibration experiments were carried out for radon measuring devices (charcoal canisters and scintillation cell) using the calibration chamber constructed in the present study.