Enhancing RHIC luminosity capabilities with in-situ beam piple coating [electronic resource].

Published:: Washington, D.C. : United States. Dept. of Energy, 2009.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Additional Creators:: Brookhaven National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

Electron clouds have been observed in many accelerators, including the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory (BNL). They can limit the machine performance through pressure degradation, beam instabilities or incoherent emittance growth. The formation of electron clouds can be suppressed with beam pipe surfaces that have low secondary electron yield. At the same time, high wall resistivity in accelerators can result in levels of ohmic heating unacceptably high for superconducting magnets. This is a concern for the RHIC machine, as its vacuum chamber in the superconducting dipoles is made from relatively high resistivity 316LN stainless steel. The high resistivity can be addressed with a copper (Cu) coating; a reduction in the secondary electron yield can be achieved with a titanium nitride (TiN) or amorphous carbon (a-C) coating. Applying such coatings in an already constructed machine is rather challenging. We started developing a robotic plasma deposition technique for in-situ coating of long, small diameter tubes. The technique entails fabricating a device comprised of staged magnetrons and/or cathodic arcs mounted on a mobile mole for deposition of about 5 {micro}m (a few skin depths) of Cu followed by about 0.1 {micro}m of TiN (or a-C).

Report Numbers:

E 1.99:bnl--81821-2009-cp
bnl--81821-2009-cp

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Published through SciTech Connect.
05/04/2009.
"bnl--81821-2009-cp"
"KB0202011"
Particle Accelerator Conference; Vancouver, B.C., Canada; 20090504 through 20090508.
Fischer, W.; Blaskiewicz, M.; Poole, H. J.; Herschcovitch,A.

Funding Information:

DE-AC02-98CH10886

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