Abstract: The invention relates to a method for indicating the presence of concealed minerals and/or deposits in prospecting or exploration operations. A flow of ascending free geogas is analyzed with respect to its content of entrained substances of exploration interest. The gas is suitably sampled at locations beneath or above the surface of the ground, and its content of carried substances caused to be released, and then collected and analyzed. The gas may suitably be caused to flow through a device in which solid substances of interest are collected for example by absorbtion and/or adsorbtion techniques. Electrically charged particles can also be collected with the aid of an electric field.

Abstract: The invention relates to a method and apparatus for measuring at least one of the parameters flow rate, flow velocity, concentration and quantity of radon and/or radon daughters in the ground. The method is characterized by collecting gas arriving from the ground in a first chamber which is gas-permeable at the bottom thereof, at least the downwardly extending boundaries of the chamber being in contact with the ground, so that atmospheric gas is prevented from passing into the chamber. At least one detector which measures alpha-radiation from the decomposition of radon and radon daughters is placed in a second chamber communicating with the first chamber. Positioning of the second chamber and the detector is selected so that the detector can continuously be observed and utilized for the measuring operation. The gas is allowed to pass continuously. through the chambers over a given period of time, to expose the detector to the gas.

Abstract: The invention relates to a method of measuring the concentration of radon and radon daughters in the ground, particularly at great depth and/or below the ground-water level. In accordance with the invention a detector is freely suspended from a wire and placed in a container intended for collecting gas rising up from the ground. The container is buried at a desired depth beneath the surface of the ground and the detector is exposed to the gas in the container over a given period of time. Subsequent to this exposure period, the detector is drawn up by means of the wire, together with a sleeve, protecting the detector from contact with surrounding ground, through the roof of the container and up through the ground, to a location so selected that the registered contents of radon and radon daughters can then be determined on the basis of the data registered on the detector. The invention also relates to preferred apparatus for carrying out the method.

Abstract: The invention relates to a method for detecting and measuring alpha-emitting substances, such as radon and/or daughter products of radon, by registering nuclear tracks on a detector. By conducting away during measuring any electrostatic field which may have built-up on the detector, there is eliminated the risk of erroneous information being obtained with respect to the dosage of radiation received.A device in the form of a dosimeter for carrying out the detecting and measuring method is also provided in accordance with the invention. Arranged on or in the immediate vicinity of the registering surface (1) of the detector is an electrically conductive material (2) which at least partially covers the registering surface. In a preferred embodiment, the dosimeter may include at least one absorber (4) arranged between the registering surface and the electrically conductive material.