Radiation detection systems
RDS Radon Calibration Chamber
RDS Radon Calibration Chamber (ERnCC)
The environmental radon calibration chamber (ERnCC) was developed to provide a "near zero" radon activity concentration in air in order to establish the background count rate of radon monitors. Three constant low-level radon activity concentrations inside the ERCC air are maintained for at least 6 – 12 hours in order to establish the count rate per unit radon activity concentration in air.
The ERnCC can provide 4 different radon level ranges:
a) Near zero RnAC;
b) 30 – 50 Bq/m3;
c) 70 – 150 Bq/m3;
d) 250 – 500 Bq/m3.
Fine fraction of the soil sediment that contains below regulatory concern 226Ra activity concentration has been used to generate radon for the ERnCC. The RnACs inside the RnCC are measured (logged) by the RDS Continuous Radon Monitor (CRnM1) that was calibrated against the European Union (EU) radon activity concentration standard.
The main features
The body of the ERnCC consists of a 0.75 m high x 0.60 m wide x 0.45 m deep enclosure that was constructed out of the 2.5 mm thick welded galvanised iron sheet. Several air inlet and outlet ports of the ERnCC were equipped with "quick connectors". The radon monitors are inserted into the ERnCC through the 0.4 m x 0.3 m opening. The opening is sealed with a 0.5 m high x 0.3 m wide and 30 mm thick clear acrylics window that is screwed against a rubber seal that is inside of a precision groove of the aluminium window frame.
An air fan mixes air inside of the ERnCC and the radon activity concentration in air is also continuously monitored by the Radiation Detection System's E-Continuous Radon Monitor (CRnM2). Measured 10 min RnAC data are sent every 10 min via wi-fi to the RDS Monitoring Platform (RDSMP).