Alpha track dosimetres offer a simple and inexpensive method of determining the radon average value over a longer measurement duration. The dosimetres are placed indoors. The measurement duration is from a few weeks up to one year. The annual average value is used for comparison with the legal guidelines.
Functionality, simplified:
- Radon gas diffuses passively into the dosimetre.
- Radon decay products are retained by the filter.
- During radioactive decay of radon, alpha particles are emitted and impact on the detector film of the dosimeter. This causes trace elements to remain.
- The dosimeters are sent to the laboratory for analysis. There the traces are made visible by using special etching methods. The traces are counted. High radon activity concentrations cause a corresponding number of traces and tracks.