Measurement of short-lived radon progenies by simultaneous alpha gamma-spectrometry at the German radon reference chamber

In the German radon reference chamber, the short-lived radon progenies are separated by a sample tube according to the attached or unattached fraction , while their activity concentration is afterwards measured by simultaneous alpha- and gamma-spectrometry. The results are expressed by the equilibriu m factor F and the unattached fraction f(p) (International Commission on Ra diological Protection, ICRP Publication 50, Ann. ICRP 17 (1987) 1). Both F and f(p), can be therefore studied with respect to the full set of environm ental parameters, e.g. temperature, humidity, air pressure and aerosol conc entration (Honig et al., Nucl. Instr. and Meth. A 416 (1998) 525). Up to no w, well-defined and stable equilibrium factors in the interval from 0.1 to 1.0 have been established. In correlation with this, the unattached fractio n can be varied from 0.01 to 0.9. The sample and measuring technique for th e short-lived radon progenies described in this work is the basis for funda mental studies with regard to the equilibrium factor and the unattached fra ction as well as for application as a calibration facility. (C) 1999 Elsevi er Science B.V. All rights reserved.