| 摘要 |
<p>This device consists of: a light source (44) capable of emitting a narrow light beam; a system for displacing this narrow beam, this system for displacing the beam comprising a means (12) of rotating the light beam in a plane cutting through the object around a point on a detection axis (X) contained in the aforesaid plane, the beam passing through this point on the detection axis, and at least one fixed mirror (18) for sending back the rotating beam, this mirror (18) meeting the cutting plane and being placed off the axis and provided in order to displace the beam reflected by it in the cutting plane obliquely with respect to the detection axis and also in order to scan the object by this reflected beam in the cutting plane; a photodetecting system (8) capable of detecting light being propagated along the detection axis and emerging from a point in the object, located in the said plane and corresponding to a predetermined position of the beam scanning the object, this position being related in one-to-one manner with the distance between the point in the object and the photodetecting system, the latter being capable of creating a signal at the moment of detection, a signal-processing system (24) enabling the point in the object to be located using this moment of detection. Application to the determination of cross-sections. <IMAGE></p> |
