| NUKLEONIKA 2009, 54(3):189-192
TEST MEASUREMENTS OF THORON CONCENTRATION USING
TWO IONIZATION CHAMBERS AlphaGUARD VS. RADON MONITOR RAD7
Elżbieta Kochowska1, Krzysztof Kozak1, Beata Kozłowska2, Jadwiga Mazur1,
Jerzy Dorda2
1 Laboratory of Radiometric Expertise,
The Henryk Niewodniczanski Institute of Nuclear
Physics, Polish Academy of Sciences,
152 Radzikowskiego Str., 31-342 Kraków, Poland
2 Nuclear Physics and Its Application Department, Institute of Physics, University of Silesia,
4 Uniwersytecka Str., 40-007 Katowice, Poland
The experiment aiming at testing the possibility of using AlphaGUARD monitors based on an ionization chamber for thoron measurements is presented. A single AlphaGUARD monitor working in the flow mode was applied to measure thoron concentration in the radon-free atmosphere. The sensitivity (correction factors) of the monitor to thoron was estimated by comparison with a RAD7 portable detector (Durridge Company), based on spectrometric analysis, in the thoron, radon-free atmosphere in a calibration chamber. This depends on the applied flow rate and changes from 8% for the flow rate of 0.3 dm3/min to 36% for
1 dm3/min. It was also revealed that the sensitivity of the monitor to thoron in the diffusion mode is equal to ca. 5% and may be neglected. The method involving two AlphaGUARD monitors working in two different modes (diffusion and flow) at the same time may be used to evaluate radon and thoron concentration in the natural environmental conditions where usually both isotopes appear together. In this method thoron concentration is estimated as the difference of results obtained from two AlphaGUARD monitors multiplied by the correction factor corresponding to the applied flow rate. The devices based on spectrometric analysis, e.g. RAD7 seem to be a better tool for thoron measurements in the environmental conditions.
Close X |