Environmental control of the German radon reference chamber

In the radon reference chamber of the PTB, radon and its progenies are measured with different systems for α- and γ-spectrometry with the full set of environmental parameters, e.g. temperature, humidity, air pressure and aerosol concentration being controlled. Measurement and control of the environmental parameters is important not only for the quality of the calibration of radon activity concentration but also absolutely necessary for all measurements of activity concentrations of radon progenies and the resulting equilibrium factors. Therefore, the basic design and construction of the chamber, the climate control, the aerosol generation and the air cleaner are properly chosen to provide stable conditions and a wide variation of the parameters. The main advantages of the German radon reference chamber with respect to the variation of environmental parameters is given in this work.