Speaker
Description
A low-power SRF test facility is currently being developed at Daresbury Laboratory as part of the superconducting thin film testing programme. The facility consists of a bulk niobium choked test cavity operating at 7.8 GHz surrounded by three RF chokes housed within a dry, liquid helium free cryostat. The cavity is able to test thin film planar samples of up to 10 cm in diameter at temperatures down to 4 K with a maximum RF power of 1 W. Having the cavity surrounded by RF chokes allows it to be physically and thermally isolated from the sample, thus reducing the need for a complicated and time consuming sample mounting procedure, while at the same time minimising the electromagnetic field leakage out of the cavity. Heaters connected to the sample allow for direct measurements of the surface resistance of samples using a DC-RF calorimetry method. Due to the simple sample mounting procedure, we are able to test samples with a fast turnaround time of two to three days per sample. This is the main advantage of this facility compared with other test facilities. When fully operational, results from RF tests will be compared alongside the thin film deposition parameters, deposited film characterisation with SEM, XPS, XRD and other techniques, and DC/AC measurements to fully analyse the performance of different thin film samples. Details of this facility will be presented at this workshop.
