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

Journal Article · Thu Dec 30 00:00:00 EST 2010 · Physical Review Special Topics. Accelerators and Beams

DOI:https://doi.org/10.1103/PhysRevSTAB.13.124702· OSTI ID:1004389

Geng, Rong -Li ^[1]; Tyagi, P. V. ^[2]; Hayano, Hitoshi ^[3]; Kato, Shigeki ^[4]; Nishiwaki, Michiru ^[3]; Saeki, Takayuki ^[3]; Sawabe, Motoaki ^[3]

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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)

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.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC05-06OR23177
• OSTI ID: 1004389
• Report Number(s): JLAB-ACC-09-1124; DOE/OR/23177-1065; TRN: US1100670
• Journal Information: Physical Review Special Topics. Accelerators and Beams, Vol. 13, Issue 12; ISSN 1098-4402
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
AUGER ELECTRON SPECTROSCOPY
CAVITIES
CHEMICAL COMPOSITION
EQUATOR
GEOMETRY
NIOBIUM
NIOBIUM OXIDES
PROBES
SCANNING ELECTRON MICROSCOPY
SULFUR
TOPOGRAPHY