Apparatus for measuring particularly quick changes in volume activity of radon in air

摘要

In the present invention, there is disclosed an apparatus for measuring especially quick changes in volume activity of radon in air being comprised of an ionizing radiation detector having a detection space enclosed in an electrically conducting jacket (1) serving as an electrostatic shield with a collecting electrode (2) reaching in the detector detection space and evaluation circuits being connected to said detector. The ionizing radiation detector consists of an alpha radiation detector employing air as a working gas and an electrically conducting grid (8) performed in a portion of the electrically conducting jacket (1) enclosing the detection space. The detector is provided with a filter (7) and in said electrically conducting jacket (1) there is performed an aperture to which a ventilation device (6) for air exchange within the detector detection space is connected. For the amount of airflow (P) generated by the ventilation device (6) and for the size of the detector detection space (V) the condition is met that the ventilation coefficient K = P/V is greater than or equal to 0.3 mine-1.