Title: Commissioning of the JLab Surface Impedance Characterization (SIC) System
Author: Charles Reece
Institution: Jefferson Lab, Newport News (VA) USA
Abstract: Binping Xiao, Larry Phillips, and Charles Reece
A system for making direct calorimetric measurements of the surface resistance at 7.5 GHz of small samples of variously prepared superconducting surfaces has been commissioned at JLab. The flat, 50 mm diameter sample temperature is regulated independently of the balance of the TE011 sapphire-loaded cavity, enabling Rs and Δλ measurements from 2 K to Tc of the sample. Initial operation, limited by available rf power, has extended to Bpk of 18 mT. The calorimeter resolution is better than 10 nΩ, and the sampled surface area is ~ 0.8 cm2. The SIC has been commissioned with a bulk Nb sample, demonstrating excellent agreement with standard BCS characterizations. Initial application to SRF thin films has begun. We are eager to apply it to non-niobium materials. Preparations for a second generation with extended dynamic range have already begun.