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Title: Surface characterization of Nb samples electropolished together with real superconducting rf accelerator cavities

Here, we report the results of surface characterizations of niobium (Nb) samples electropolished together with a single cell superconducting radio-frequency accelerator cavity. These witness samples were located in three regions of the cavity, namely at the equator, the iris and the beam-pipe. Auger electron spectroscopy (AES) was utilized to probe the chemical composition of the topmost four atomic layers. Scanning electron microscopy with energy dispersive X-ray for elemental analysis (SEM/EDX) was used to observe the surface topography and chemical composition at the micrometer scale. A few atomic layers of sulfur (S) were found covering the samples non-uniformly. Niobium oxide granules with a sharp geometry were observed on every sample. Some Nb-O granules appeared to also contain sulfur.
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [3] ;  [3] ;  [3]
  1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
  2. Graduate University for Advanced Studies, School of Advanced Sciences (GUAS/AS), Ibaraki (Japan)
  3. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)
  4. Graduate University for Advanced Studies, School of Advanced Sciences (GUAS/AS), Ibaraki (Japan); High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)
Publication Date:
OSTI Identifier:
1004389
Report Number(s):
JLAB-ACC--09-1124; DOE/OR/23177--1065
Journal ID: ISSN 1098-4402; TRN: US1100670
Grant/Contract Number:
AC05-06OR23177
Type:
Accepted Manuscript
Journal Name:
Physical Review Special Topics. Accelerators and Beams
Additional Journal Information:
Journal Volume: 13; Journal Issue: 12; Journal ID: ISSN 1098-4402
Publisher:
American Physical Society (APS)
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; AUGER ELECTRON SPECTROSCOPY; CAVITIES; CHEMICAL COMPOSITION; EQUATOR; GEOMETRY; NIOBIUM; NIOBIUM OXIDES; PROBES; SCANNING ELECTRON MICROSCOPY; SULFUR; TOPOGRAPHY