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

Geng, Rong -Li; Tyagi, P. V.; Hayano, Hitoshi; Kato, Shigeki; Nishiwaki, Michiru; Saeki, Takayuki; Sawabe, Motoaki

doi:10.1103/PhysRevSTAB.13.124702

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

Full Record
Other Related Research

Abstract

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:

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

Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Graduate University for Advanced Studies, School of Advanced Sciences (GUAS/AS), Ibaraki (Japan)
High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)
Graduate University for Advanced Studies, School of Advanced Sciences (GUAS/AS), Ibaraki (Japan); High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)

Publication Date:: Thu Dec 30 00:00:00 EST 2010

Research Org.:: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

Sponsoring Org.:: USDOE Office of Science (SC)

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

Resource 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)

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

Citation Formats


                    Xin Zhao, Geng, Rong -Li, Tyagi, P. V., Hayano, Hitoshi, Kato, Shigeki, Nishiwaki, Michiru, Saeki, Takayuki, and Sawabe, Motoaki. Surface characterization of Nb samples electropolished together with real superconducting rf accelerator cavities.  United States: N. p., 2010. 
Web.  doi:10.1103/PhysRevSTAB.13.124702.

Copy to clipboard


                    Xin Zhao, Geng, Rong -Li, Tyagi, P. V., Hayano, Hitoshi, Kato, Shigeki, Nishiwaki, Michiru, Saeki, Takayuki, & Sawabe, Motoaki. Surface characterization of Nb samples electropolished together with real superconducting rf accelerator cavities.  United States.  https://doi.org/10.1103/PhysRevSTAB.13.124702

Copy to clipboard


                    Xin Zhao, Geng, Rong -Li, Tyagi, P. V., Hayano, Hitoshi, Kato, Shigeki, Nishiwaki, Michiru, Saeki, Takayuki, and Sawabe, Motoaki. Thu .  
"Surface characterization of Nb samples electropolished together with real superconducting rf accelerator cavities".  United States.  https://doi.org/10.1103/PhysRevSTAB.13.124702.  https://www.osti.gov/servlets/purl/1004389.

Copy to clipboard


                    
@article{osti_1004389,

  title        = {Surface characterization of Nb samples electropolished together with real superconducting rf accelerator cavities},

  author       = {Xin Zhao and Geng, Rong -Li and Tyagi, P. V. and Hayano, Hitoshi and Kato, Shigeki and Nishiwaki, Michiru and Saeki, Takayuki and Sawabe, Motoaki},

  abstractNote = {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.},

  doi          = {10.1103/PhysRevSTAB.13.124702},

  journal      = {Physical Review Special Topics. Accelerators and Beams},

  number       = 12,

  volume       = 13,

  place        = {United States},

  year         = {Thu Dec 30 00:00:00 EST 2010},

  month        = {Thu Dec 30 00:00:00 EST 2010}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.1103/PhysRevSTAB.13.124702

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 6 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Similar Records in DOE PAGES and OSTI.GOV collections:

Surface characterization of niobium samples electropolished together with real cavities

Conference Zhao, Xin ; Geng, Rongli

We report the results of surface characterization of niobium samples electropolished together with single-cell niobium cavities. These witness samples were located in three regions of the cavity, namely at the equator, the iris and the beam-pipe respectively. 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 weremore »« less
https://doi.org/10.2172/1998860

Full Text Available
SURFACE CHARACTERIZATION OF NIOBIUM SAMPLES ELECTRO-POLISHED TOGETHER WITH REAL CAVITIES

Conference Zhao, Xin ; Geng, Rongli ; Funahashi, Y. ; ...

We report the results of surface characterizations of niobium samples electropolished together with single cell cavities. 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 sulphur (S) were found covering the samples non-uniformly. Niobium oxide granules with a sharp geometry were observedmore »« less
Full Text Available
Highly smooth Nb surfaces fabricated by buffered electropolishing

Journal Article Wu, Andy T ; Mammossor, John ; Phillips, H ; ...

It is demonstrated that highly smooth Nb surfaces can be obtained through Buffered ElectroPolishing (BEP) employing an electrolyte consisting of lactic, sulfuric, and hydrofluoric acids. Parameters that control the polishing process are optimized to achieve the smoothest surface finish with the help of surface observations using a scanning electron microscope and a Metallographic Optical Microscope (MOM). The polishing rate of BEP is determined to be 0.646 {micro}m/min that is much higher than 0.381 {micro}m/min achieved by the conventional ElectroPolishing (EP) process widely used in the Superconducting Radio Frequency (SRF) community. A high precision and large scan area 3-D profilometer ismore »« less
Full Text Available
Topographic evolution of heat-treated Nb upon electropolishing for superconducting rf applications

Journal Article Lechner, Eric M. ; Angle, Jonathan W. ; Baxley, Carrie ; ... - Physical Review Accelerators and Beams

Surface finish plays an essential role in the performance of superconducting radio frequency cavities. Several surface treatments have been developed to reduce surface resistance at modest accelerating gradient. We investigated the effects of sequential electropolishing on samples vacuum heat treated at 300 °C and 600 °C and N-doped Nb samples using atomic force microscopy. Most notably, N-doping promotes the growth of surface niobium nitrides during high-temperature heat treatment in a nitrogen atmosphere. The surface is left as a two-phase system composed of N-doped Nb substrate with nitrides protruding into the surface and preferentially growing at grain boundaries. During electropolishing, themore »« less
https://doi.org/10.1103/PhysRevAccelBeams.26.103101
Detailed Nb Surface Morphology Evolution During Electropolishing for SRF Cavity Production

Conference Tian, H. ; Reece, C. E. ; Dole, Nikhil ; ...

Electropolishing of niobium is currently an important part of attaining the best performance of SRF cavities. We endeavor to develop sufficient understanding of the process dynamics to gain predictive power over specific topographies subjected to controlled electropolishing conditions. This work examines the evolution of highly reproducible Nb surface morphology produced by centrifugal barrel polishing (CBP) of fine-grain and single-crystal material as this material is electropolished under different well-controlled conditions. The morphology evolution of Nb surface has been described using a combined approach of scaling analysis and predictions of the electropolishing theory. Our results shows that electropolishing at low temperature (<25more »« less
Full Text Available

Similar Records