Improved method for minimizing vibrational motion transmitted by pumping lines.

A description is given for a technique that is very effective in reducing vibrations transmitted along large-diameter ( greater, similar8 cm) vacuum and gas pumping lines. This technique uses a supported double-gimbal metal bellows design. When compared with other techniques such as the crossed T metal bellows design, a factor of 7 improvement was measured. An analysis is included which compares the various techniques, and shows that, in principle, improvement factors as high as 80 or more can be realized with the double-gimbal design.