| 摘要 |
<p>The invention comprises a method and apparatus for detecting the presence of a number of substances such as explosives or drugs in a container such as luggage (10) at an airport. The containers, travelling on a conveyor (15) for example are irradiated with fast neutron and gamma source radiation (6) preferably simultaneously and preferably of different frequencies. The radiation is detected (7) and the extent to which each species of the source radiation is transmitted through the container is measured. The measurements are analysed with reference to the known characteristic attenuation coefficients and density properties of the substances for each species of the source radiation.</p> |
