Measuring chamber for determining alpha activity of radon gas in carrier gas esp. air - has detector producing measurement signal for detecting alpha particles produced with radon conversion in chamber and unit for producing electric field.

摘要

The unit for producing the electric field (10) has at least one electret, and attracts electrically charged daughter nuclides from the effective vol., at a distance to the first detector (2, 3). This distance is greater than the range of the most energy rich alpha particles in the carrier gas, emitted by the radon daughter nuclides. The chamber (1) includes at least one further alpha detectors (4, 7, 8), producing a measurement signal (M2). This detector is so arranged in the chamber, that it can detect alpha particles which are emitted from charged radon daughter nuclides, sucked from the effective vol. of the detector (2, 3) producing the first measurement signal (M1). The further detector detects alpha particles which are emitted from the radon itself and uncharged radon daughter nuclides. It has a smaller detection sensitivity than the first detector (2, 3). ADVANTAGE - Gives quicker and more exact determination of alpha activity of radon in carrier gas than units of this type hitherto.