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Title: Experiment and Results on Plasma Etching of SRF cavities

The inner surfaces of SRF cavities are currently chemically treated (etched or electropolished) to achieve the state of the art RF performance. We designed an apparatus and developed a method for plasma etching of the inner surface for SRF cavities. The process parameters (pressure, power, gas concentration, diameter and shape of the inner electrode, temperature and positive dc bias at inner electrode) are optimized for cylindrical geometry. The etch rate non-uniformity has been overcome by simultaneous translation of the gas point-of-entry and the inner electrode during the processing. A single cell SRF cavity has been centrifugally barrel polished, chemically etched and RF tested to establish a baseline performance. This cavity is plasma etched and RF tested afterwards. The effect of plasma etching on the RF performance of this cavity will be presented and discussed.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2]
  1. Old Dominion Univ., Norfolk, VA (United States)
  2. Jefferson Lab., Newport News, VA (United States)
Publication Date:
OSTI Identifier:
1221917
Report Number(s):
JLAB-ACC--15-2085; DOE/OR/23177--3545
DE-SC0007879; TRN: US1601461
DOE Contract Number:
AC05-06OR23177
Resource Type:
Conference
Resource Relation:
Conference: IPAC 2015, Richmond, VA (United States), 3-8 May 2015
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26); USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ETCHING; SUPERCONDUCTING CAVITY RESONATORS; PLASMA; PERFORMANCE; CYLINDRICAL CONFIGURATION; SURFACES; COMPARATIVE EVALUATIONS