Author(s)
|
Hershcovitch, A. (Brookhaven) ; Blaskiewicz, M. (Brookhaven) ; Brennan, J.M. (Brookhaven) ; Chawla, A. (Brookhaven) ; Fischer, W. (Brookhaven) ; Liaw, C-J (Brookhaven) ; Meng, W. (Brookhaven) ; Todd, R. (Brookhaven) ; Custer, A. ; Erickson, M. ; Jamshidi, N. ; Kobrin, P. ; Laping, R. ; Poole, H.J. ; Jimenez, J.M. (CERN) ; Neupert, H. (CERN) ; Taborelli, M. (CERN) ; Yin-Vallgren, C. (CERN) ; Sochugov, N. (Tomsk, Inst. H. C. Electronics) |
Note
| Comments: 8 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Italy 8 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Italy |
Abstract
| To rectify the problems of electron clouds observed in RHIC and unacceptable ohmic heating for superconducting magnets that can limit future machine upgrades, we started developing a robotic plasma deposition technique for $in-situ$ coating of the RHIC 316LN stainless steel cold bore tubes based on staged magnetrons mounted on a mobile mole for deposition of Cu followed by amorphous carbon (a-C) coating. The Cu coating reduces wall resistivity, while a-C has low SEY that suppresses electron cloud formation. Recent RF resistivity computations indicate that 10 {\mu}m of Cu coating thickness is needed. But, Cu coatings thicker than 2 {\mu}m can have grain structures that might have lower SEY like gold black. A 15-cm Cu cathode magnetron was designed and fabricated, after which, 30 cm long samples of RHIC cold bore tubes were coated with various OFHC copper thicknesses; room temperature RF resistivity measured. Rectangular stainless steel and SS discs were Cu coated. SEY of rectangular samples were measured at room; and, SEY of a disc sample was measured at cryogenic temperatures. |