Prototype of a primary calibration system for measurement of radon activity concentration.
To calibrate measurement devices for monitoring the activity concentration of (222)Rn in air, a prototype of a calibration facility is tested using a solid (226)Ra source and a high-purity germanium (HPGe) detector. An emanation box was mounted on the detector for online gamma measurements. Inside this box, a 32.8 kBq ±3% (226)Ra standard source was placed. An AlphaGUARD control radon monitor was connected to the emanation box with a pumping air system in an open flow mode as a reference monitor. The emanation coefficient of the source was controlled online by comparing the gamma activity of (214)Bi (Eγ=609.3 keV), progeny of (226)Ra, to that of the calibration source. A standard (137)Cs source, installed within the emanation box, was used as a reference for gamma spectroscopy using the HPGe detector, with a total systematic error of 4% and a random error less than 2%. The ratio between gamma measurements and AlphaGUARD was 0.94±0.4; which is within the 9% uncertainties of AlphaGUARD calibration.
Ural Federal University, Ekaterinburg, Russia. Electronic address: Mostafa_85@mail.ru.
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Mostafa
Ural Federal University, Ekaterinburg, Russia; Institute of Industrial Ecology UB RAS, Ekaterinburg, Russia.
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Vasyanovich
Institute of Industrial Ecology UB RAS, Ekaterinburg, Russia.
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Zhukovsky
Emanation factor; Radon; Radon decay products; Radon standard source