| 摘要 |
<p>The invention is a method and apparatus for performing a radiation scan of a structure (10) by arranging a source (18) of penetrating radiation and a radiation detector (20) at opposed ends of a radiation path through the structure, oriented in such a way that the source emits radiation along the path through the structure and the detector is capable of detecting the radiation after it has passed through the structure and monitoring the radiation emitted from the source that is detected by the detector; comprising mounting at least one continuous loop of a cable (16) on the structure between at least two fixed locations (22, 24) on said structure so that the cable is movable along its length relative to the structure, fixing at least one of the source of penetrating radiation and the radiation detector to the cable, arranging the other of the source and detector to emit radiation to or detect radiation from the source or detector that is fixed to the cable, monitoring the radiation received by the detector when the cable is in a first position, moving the cable along its longitudinal axis to move the source or detector fixed to the cable to a second position relative to said structure and monitoring the radiation received by the detector in the second position. Preferably both source and detector are fixed to the cable so that movement of the cable moves the source and detector by the same distance in the same direction.</p> |
