PAC09 - List of Authors (Xiao, B.)

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Xiao, B.

Paper	Title	Page
WE5PFP061	Commissioning of the SRF Surface Impedance Characterization System at Jefferson Lab	2144
	B. Xiao, R.L. Geng, F. Marhauser, H.L. Phillips, C.E. Reece, H. Wang JLAB, Newport News, Virginia M.J. Kelley The College of William and Mary, Williamsburg
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Much remains to be learned regarding the details of SRF performance effects with material variation, including niobium treated in different ways, and different bulk/thin film materials that are fabricated under different conditions. A facility that can measure small samples’ RF properties in a range of 0~180mT magnetic field and 2~20k temperature is necessary in order to answer this question. The Jefferson Lab surface impedance characterization (SIC) system has been designed to attempt to meet this requirement. The SIC system uses a sapphire-loaded cylindrical Nb cavity at 7.5GHz with 50mm diameter flat sample placed on a non-contacting end plate and a calorimetric technique to directly measure the rf dissipation in the sample in response to known rf fields over ~1 cm². We report on the commissioning of this system and its first uses for characterizing materials. Preliminary tests with Nb thin film sample sputtered on Cu substrate, and bulk Nb sample have been done at low field. The presently available hardware is expected to enable tests up to 20 mT peak magnetic field on the sample CW. Paths to higher field tests have been identified.

Paper

Title

Page

WE5PFP061

Commissioning of the SRF Surface Impedance Characterization System at Jefferson Lab

2144

B. Xiao, R.L. Geng, F. Marhauser, H.L. Phillips, C.E. Reece, H. Wang
JLAB, Newport News, Virginia
M.J. Kelley
The College of William and Mary, Williamsburg

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.

Much remains to be learned regarding the details of SRF performance effects with material variation, including niobium treated in different ways, and different bulk/thin film materials that are fabricated under different conditions. A facility that can measure small samples’ RF properties in a range of 0~180mT magnetic field and 2~20k temperature is necessary in order to answer this question. The Jefferson Lab surface impedance characterization (SIC) system has been designed to attempt to meet this requirement. The SIC system uses a sapphire-loaded cylindrical Nb cavity at 7.5GHz with 50mm diameter flat sample placed on a non-contacting end plate and a calorimetric technique to directly measure the rf dissipation in the sample in response to known rf fields over ~1 cm². We report on the commissioning of this system and its first uses for characterizing materials. Preliminary tests with Nb thin film sample sputtered on Cu substrate, and bulk Nb sample have been done at low field. The presently available hardware is expected to enable tests up to 20 mT peak magnetic field on the sample CW. Paths to higher field tests have been identified.