| 摘要 |
Two detectors mounted on footprints (12) and (13) of a plate (5) can be permuted and placed in turn in front of a measuring location set in a plate (1) connected to the plate (5). Concentric sealing joints (24, 25) bound with the plates (1, 5) a closed cavity wherein a vacuum should be created to perform measurements. The joints enable the plate to be mutually moved without sealing loss. The invention is however applicable to any device implying a relative displacement of two parts in front of each other, a stronger pressure existing outside of the parts than between them, which tends to collapse them against each other. |
