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Thoron progeny chamber commissioned for calibration


Due to a short half-life, it is difficult to collect data on Thoron (220Rn) in metrology and therefore, only very little is known about its influence. This is a problematic issue since, due to the different energies and half-lives in this decay chain, a 220Rn concentration yields a dose which is higher by a factor 14 (!) than a comparable 222Rn concentration. PTB has therefore introduced the project "Production and investigation of defined thoron progeny reference fields for the calibration of thoron progeny measuring instruments" into the environmental research plan (UFO Plan, BMU - Federal Environment Ministry) for the realisation of the unit Bq/m3 so that, in the future and thanks to quality assurance, reliable data on 222Rn and 220Rn measuring systems are available for radioprotection and epidemiologic research. The project was successfully completed at the end of 2007.

The chamber has been in operation since January 2008; the first orders for calibrations came from clients based in the EU.