AVS 61st International Symposium & Exhibition
    Vacuum Technology Wednesday Sessions
       Session VT-WeM

Paper VT-WeM13
e-Cloud Activity of DLC Coated Chamber at FNAL Main Injector

Wednesday, November 12, 2014, 12:00 pm, Room 303

Session: Accelerator and Large Vacuum Systems I
Presenter: Shigeki Kato, KEK-High Energy Accelerator Research Organization, Japan
Authors: S. Kato, KEK-High Energy Accelerator Research Organization, Japan
J. Eldred, Indiana University
C.Y. Tan, FNAL
M. Backfish, FNAL
B. Zwaska, FNAL
Correspondent: Click to Email
Carbon material that has a low mass density (resulting a long electron penetration depth in bulk), a low δmax and a low secondary electron yield is of good option to mitigate electron cloud activity in particle beam chambers. In addition to this, diamond-like-carbon (DLC) coating on beam chambers would give advantages of a large deposition rate (a couple of μm/h ), inexpensiveness(~US$800.- /m for coating of 100m), a good uniformity(±5%) and coating applicability on any type of beam chamber ( even bent one ) and on any material without requirement of magnetic field. A DLC coated stainless steel chamber and a reference stainless chamber were installed into the FNAL main injector simultaneously in order to investigate e-cloud activity in the chambers with three retarding field analyzers(RFAs). Preliminary results at the low beam intensity showed RFA signals in the DLC coated chamber showed only 1/100 of that in the steel chamber. The e-cloud activity at the higher beam intensity and comparison of e-cloud activity at usually prepared surface (smooth surface) with roughed surface to aim further reduction of the activity will be also reported in the presentation.