| 摘要 |
PCT No. PCT/NZ93/00025 Sec. 371 Date Oct. 11, 1994 Sec. 102(e) Date Oct. 11, 1994 PCT Filed Apr. 14, 1993 PCT Pub. No. WO93/21546 PCT Pub. Date Oct. 28, 1993.A method and apparatus detects 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 of radiation is transmitted through the container is measured. The measurements are analyzed with reference to the known characteristic attenuation coefficients and density properties of those substances for each species of the source radiation. |
