Abstract: Device to implement the method according to claim 1, wherein it is constituted of a vessel (2) provided with an intake tube (4) and an evacuation tube (8) for the gaseous atmosphere and whose inside forms the closed sampling space, is subdivided into a large number of small elementary intercommunicating volumes so as to enable the taken gaseous sample to be homogenized, as well as to allow for the diffusion and the spatially homogeneous trapping of all the solid daughter products thus constituting a homogeneous emitting source for the spectrometry chain which examines this source from outside.

Abstract: Process for the detection of atmospheric contamination by alpha particle aerosols eliminating the background noise due to radon daughter nuclei, of the type consisting of collecting, by circulation of the atmospheric air, the alpha particles to be detected on a filter placed in front of a detection and counting system, wherein there is discrimination between the alpha particles present in the atmosphere coming from a polluting source and which it is wished to detect and count and the alpha particles constituting the background noise and which are normally present in the atmosphere, on the basis of their different grain sizes. The invention also relates to a portable detector for performing the aforementioned process. Application to monitoring the ambient air of laboratories, etc.

Abstract: The present invention relates to a pressure reducing device and to an apparatus for detecting aerosols and particularly aerosols of solid particles emitting .alpha. rays. This apparatus comprises a measuring chamber equipped with a sampling filter and a radiation detector and linked with the outside by an inlet pipe and an outlet pipe. The inlet pipe is equipped with a venturi tube making it possible to produce a pressure reduction in the measuring chamber and exert on the solid particles of the aerosol fluid flow forces exceeding the forces tending to make these particles adhere to the walls. Application to the detection of .alpha. radiation emitting aerosols.