Determination of moisture in porous materials by means of nuclear measurement techniques

In specific cases nuclear measurement techniques can advantageously be used to determine the moisture contents in porous materials. Two techniques are discussed. In the first technique a fast neutron source is used in combination with a thermal neutron detector and the second technique requires a gamma source and a gamma detector. The principle of the first method is based on the fact that moisture has a large neutron slowing-down power. The second method is based on intensity attenuation by passing matter. The theoretical aspects of both techniques are discussed as well as the actual way that the measurements can be carried out. Both techniques have successfully been applied for a number of years to determine the moisture content in coal, constructional materials, casting sand, peat, wood, ashes and slags. The measurements, which can be performed fast and are reproductive, have an accuracy of 1-2%. 6 figs., 3 tabs., 8 refs