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001-es BibID:	BIBFORM019351
Első szerző:	Papp Zoltán (fizikus)
Cím:	An intercomparison between gross [alpha] counting and gross [beta] counting for grab-sampling determination of airborne radon progeny and thoron progeny / Z. Papp
Dátum:	2006
ISSN:	0168-9002
Megjegyzések:	The instantaneous values of the airborne activity concentrations of radon progeny and thoron progeny have been determined 34 timesin a closed and windowless room in a cellar using two independent grab-sampling methods in order to compare the performance of themethods. The activity concentration of radon (222Rn) was also measured and it varied between 200 and 650 Bq/m3. Two samples ofradon and thoron progeny were collected simultaneously from roughly the same air volume by filtering. For the first method, the isotopeswere collected on membrane filter and gross a counting was applied over several successive time intervals. This method was a slightlyimproved version of the methods that are applied generally for this reason for decades. For the second method, the isotopes werecollected on glass-fibre filter and gross b counts were registered over several time intervals. This other method was developed a few yearsago and the above series of measurements was the first opportunity to make an intercomparison between it and another similar methodbased on a counting. Individual radon progeny and thoron progeny activity concentrations (for the isotopes 218Po, 214Pb, 214Bi and212Pb) were evaluated by both methods. The detailed investigation of the results showed that the systematic deviation of the methods issmall but significant and isotope-dependent. The weighted averages of the b/a activity concentration ratios for 218Po, 214Pb, 214Bi,EEDC222 (Equilibrium-Equivalent Decay-product Concentration of radon progeny) and 212Pb were 0.9970.03, 0.9070.02, 1.0370.02,0.9670.02 and 0.8070.03, respectively. The source of the systematic deviation is probably the inaccurate knowledge of the countingefficiencies mainly in the case of the a-counting method. A significant random-type difference between the results obtained with the twomethods has also been revealed. For example, the b/a ratio for EEDC222 varied between 0.8170.01 and 1.2270.03, where the errorsderive from the random errors of the independent b and a results. The detailed investigation of the results showed that the a method isresponsible for the overwhelming part of this random deviation that was caused mainly by the lower accuracy, stability and reliability ofthis method. The performance of the b method proved to be better mainly because of its higher accuracy, stability and reliability.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Radon progeny Thoron progeny Absolute beta counting GM-counter
Megjelenés:	Nuclear Instruments & Methods In Physics Research Section A-Accelerators Spectrometers Detectors And Associated Equipment. - 558 : 2 (2006), p. 569-575. -
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