Devices for SRF material characterization

Journal Article · Fri Oct 07 00:00:00 EDT 2016 · Superconductor Science and Technology

DOI:https://doi.org/10.1088/0953-2048/30/1/013001· OSTI ID:1329797

Goudket, Philippe ^[1]; Xiao, B. ^[2]; Junginger, T. ^[3]

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1. STFC Daresbury Lab. (United Kingdom). Cockcroft Inst. of Accelerator Science and Technology (AST)
2. Brookhaven National Lab. (BNL), Upton, NY (United States)
3. TRIUMF, Vancouver, BC (Canada); Helmholtz-Zentrum Berlin (HZB), (Germany). German Research Centre for Materials and Energy

The surface resistance Rs of superconducting materials can be obtained by measuring the quality factor of an elliptical cavity excited in a transverse magnetic mode (TM010). The value obtained has however to be taken as averaged over the whole surface. A more convenient way to obtain Rs, especially of materials which are not yet technologically ready for cavity production, is to measure small samples instead. These can be easily man ufactured at low cost, duplicated and placed in film deposition and surface analytical tools. A commonly used design for a device to measure Rs consists of a cylindrical cavity excited in a transverse electric (TE110) mode with the sample under test serving as one replaceable endplate. Such a cavity has two drawbacks. For reasonably small samples the resonant frequency will be larger than frequencies of interest concerning SRF application and it requires a reference sample of known Rs. In this article we review several devices which have been designed to overcome these limitations, reaching sub - nΩ resolution in some cases. Some of these devices also comprise a parameter space in frequency and temperature which is inaccessible to standard cavity tests, making them ideal tools to test theoretical surface resistance models.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: SC00112704; AC02-98CH10886; SC0004410; AC05-06OR23177
• OSTI ID: 1329797
• Alternate ID(s): OSTI ID: 1332138
• Report Number(s): BNL-112739-2016-JA; R&D Project: KBCH139; 18034; KB0202011; TRN: US1700109
• Journal Information: Superconductor Science and Technology, Vol. 30, Issue 1; ISSN 0953-2048
• Publisher: IOP Publishing
• Country of Publication: United States
• Language: English

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