Title: Novel techniques and devices for in-situ film coatings of long, small diameter tubes or elliptical and other surface contours

Abstract

In this study, devices and techniques that can, via physical vapor deposition,coat various surface contours or very long small aperture pipes, are described. Recently, a magnetron mole was developed in order to in-situ coat accelerator tube sections of the Brookhaven National Lab relativistic heavy ion collider that have 7.1 cm diameter with access points that are 500 m apart, for copper coat the accelerator vacuum tube in order to alleviate the problems of unacceptable ohmic heating and of electron clouds. A magnetron with a 50 cm long cathode was designed fabricated and successfully operated to copper coat a whole assembly containing a full-size, stainless steel, cold bore, of the accelerator magnet tubing connected to two types bellows, to which two additional pipes made of accelerator tubing were connected. The magnetron is mounted on a carriage with spring loaded wheels that successfully crossed bellows and adjusted for variations in vacuum tube diameter, while keeping the magnetron centered. Electrical power and cooling water were fed through a cable bundle. The umbilical cabling system, which is enclosed in a flexible braided metal sleeve, is driven by a motorized spool. To increase cathode lifetime, movable magnet package was developed, and thickest possible cathode wasmore » made, with a rather challenging target to substrate distance of less than 1.5 cm. Optimized process to ensure excellent adhesion was developed. Coating thickness of 10 μm Cu passed all industrial tests and even exceeded maximum capability of a 12 kg pull test fixture. Room temperature radio frequency (RF) resistivity measurement indicated that 10 μm Cu coated stainless steel accelerator tube has conductivity close to copper tubing. Work is in progress to repeat the RF resistivity measurement at cryogenic temperatures. Over 20 years ago, a device using multi axis robotic manipulators controlling separate robotic assemblies resulted in nine-axes of motion combined with conformal shape of the cathodes that can adapt to various curved surface contours was developed and successfully used for depositing optical coating on aircraft canopies. The techniques can be utilized for in situ coating of elliptical and other surface contour RF cavities and long beam pipes with thick superconducting films. Plans are to incorporate ion assisted deposition in those techniques for attaining dense, adherent and defect free coatings.« less

Authors:

Hershcovitch, Ady ^[1]; Blaskiewicz, Michael ^[1]; Brennan, Joseph Michael ^[1]; Fischer, Wolfram ^[1]; Liaw, Chong -Jer ^[1]; Meng, Wuzhang ^[1]; Todd, Robert ^[1]; Custer, Art ^[2]; Dingus, Aaron ^[2]; Erikson, Mark ^[2]; Jamshidi, Nader ^[2]; Poole, Henry Joe ^[2]

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+ Show Author Affiliations

1. Brookhaven National Lab. (BNL), Upton, NY (United States)
2. PVI, Oxnard, CA (United States)

Publication Date:

Thu Jul 30 00:00:00 EDT 2015

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Nuclear Physics (NP)

OSTI Identifier:

1228863

Report Number(s):

BNL-108602-2015-JA
Journal ID: ISSN 2166-2746; JVTBD9; R&D Project: KBCH139; 18033; KB0202011

Grant/Contract Number:  

SC00112704

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Vacuum Science and Technology B

Additional Journal Information:

Journal Volume: 33; Journal Issue: 5; Journal ID: ISSN 2166-2746

Publisher:

American Vacuum Society/AIP

Country of Publication:

United States

Language:

English

Subject:

43 PARTICLE ACCELERATORS; metallic coatings; copper; relativistic heavy ion collisions; cathode; magnets