Journal of Vacuum Science & Technology A, Vol.16, No.3, 1137-1138, 1998
Design of a low cost, low magnetic susceptibility, ultrahigh vacuum compatible, flanged electrical break
At Brookhaven National Laboratory, the g-2 experiment, a muon storage ring, requires a totally nonmagnetic vacuum system. All the vacuum components must have a low magnetic Susceptibility. The design of the beam vacuum system requires hanged electrical breaks on pumping manifolds in order to prevent ground loops. The electrical breaks developed at Brookhaven consist of a ceramic disk clamped between two Conflat flanges. A nonconductive retaining ring is used to support and center the ceramic disk and Seals with respect to the flanges. Two Helicoflex Delta seals are used to seal the flanges to the ceramic disk which has metallized surfaces in the seal area. Threaded rods which are electrically insulated from the flanges with bushings are used to provide the clamping force necessary to compress the vacuum seals. The assembly remains leak tight after repeated bakeouts up to 200 degrees C. This design offers several advantages over commercially available Conflat hanged ceramic breaks. These breaks do not use Kovar and are totally nonmagnetic. In addition to the cost being lower the overall length of the break is much shorter than commercial breaks. The same design concepts can be used for different sized Conflat flanges and for other types of flanges. The detailed design and the performance of this break are presented in this article.