Process for manufacturing hollow fused-silica insulator cylinder

Patent · Sun Dec 31 23:00:00 EST 2000

OSTI ID:874171

Sampayan, Stephen E ^[1]; Krogh, Michael L ^[2]; Davis, Steven C ^[2]; Decker, Derek E ^[3]; Rosenblum, Ben Z ^[4]; Sanders, David M ^[5]; Elizondo-Decanini, Juan M ^[6]

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1. Manteca, CA
2. Lee's Summit, MO
3. Discovery Bay, CA
4. Overland Park, KS
5. Livermore, CA
6. Albuquerque, NM

A method for building hollow insulator cylinders that can have each end closed off with a high voltage electrode to contain a vacuum. A series of fused-silica round flat plates are fabricated with a large central hole and equal inside and outside diameters. The thickness of each is related to the electron orbit diameter of electrons that escape the material surface, loop, and return back. Electrons in such electron orbits can support avalanche mechanisms that result in surface flashover. For example, the thickness of each of the fused-silica round flat plates is about 0.5 millimeter. In general, the thinner the better. Metal, such as gold, is deposited onto each top and bottom surface of the fused-silica round flat plates using chemical vapor deposition (CVD). Eutectic metals can also be used with one alloy constituent on the top and the other on the bottom. The CVD, or a separate diffusion step, can be used to defuse the deposited metal deep into each fused-silica round flat plate. The conductive layer may also be applied by ion implantation or gas diffusion into the surface. The resulting structure may then be fused together into an insulator stack. The coated plates are aligned and then stacked, head-to-toe. Such stack is heated and pressed together enough to cause the metal interfaces to fuse, e.g., by welding, brazing or eutectic bonding. Such fusing is preferably complete enough to maintain a vacuum within the inner core of the assembled structure. A hollow cylinder structure results that can be used as a core liner in a dielectric wall accelerator and as a vacuum envelope for a vacuum tube device where the voltage gradients exceed 150 kV/cm.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• DOE Contract Number: W-7405-ENG-48
• Assignee: The United States of America as represented by the United States Department (Washington, DC)
• Patent Number(s): US 6331194
• OSTI ID: 874171
• Country of Publication: United States
• Language: English

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