9th International Workshop on Thin Films and New Ideas for Pushing the Limits of RF Superconductivity

Session

RF and material characterization for SRF films

Mar 18, 2021, 8:00 AM

Virtual Edition

Conveners

RF and material characterization for SRF films: Part 1

• Reza Valizadeh (STFC Daresbury)

RF and material characterization for SRF films: Part 2

• Marc Wenskat (DESY)

RF and material characterization for SRF films: Discussion

• Tobias Junginger (University of Victoria and TRIUMF)

28. Overview of thin-film studies at KEK and Kyoto University.

Takayuki Saeki (KEK)

3/18/21, 8:00 AM

RF and material characterization for SRF films

We have a system for the third harmonic measurement of thin-film sample at KEK, and NbN thin-film samples were measured. We have another system for the third harmonic measurement of thin-film sample at Kyoto University and NbN and NbTiN thin-film samples were measured. The NbN thin-film samples were created by ULVAC, Inc. in collaboration with KEK. The NbTiN thin-film sample was created by...

29. Development of 3 Ghz cavities at KEK

Takayuki Saeki (KEK)

3/18/21, 8:20 AM

RF and material characterization for SRF films

Construction of test system for 3.0-GHz single-cell cavity at KEK.
Measurement system for lambda of thin-film sample at Kyoto University

24. A low power test facility for SRF thin film testing with high sample throughput rate

Daniel Seal (Cockcroft Institute/Lancaster University)

3/18/21, 8:40 AM

RF and material characterization for SRF films

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...

26. Upgrades to the Cornell sample host cavity

Thomas Oseroff (Cornell University)

3/18/21, 9:00 AM

RF and material characterization for SRF films

The Cornell sample host cavity was designed to measure the surface resistance of 5” diameter disks at 4 GHz as a function of temperature and RF field strength. Major changes to the system have been completed, including the addition of a transmitted power probe and a complete redesign of the fundamental power coupler. Calibration results demonstrating the improved performance are presented...

4. A New Quadrupole Resonator for SRF R&D

Marc Wenskat (DESY)

3/18/21, 9:20 AM

RF and material characterization for SRF films

As superconducting radio-frequency (SRF) cavities are now approaching the theoretical limits of the material, a variety of different surface treatments have been developed to further improve their performance; although no fully understood theory is yet available. Small superconducting samples are studied to characterize their material properties and their evolution under different surface...

34. INVESTIGATION OF SIS MULTILAYER FILMS AT HZB

Dmitry Tikhonov (Helmholtz Zentrum Berlin)

3/18/21, 10:00 AM

RF and material characterization for SRF films

The systematic study of multilayer SIS films (Superconductor-Insulator-Superconductor) is being conducted in Helmholtz-Zentrum Berlin. Such films theoretically should boost the performance of superconducting cavities, and reduce some problems related to bulk Nb such as magnetic flux trapping. Up to now such films have been presented in theory, but the RF performance of those structures have...

11. Investigation of Local Nonlinear Microwave Response of Nb3Sn and Nb-on-Cu in the Superconducting State

Chung-Yang Wang

3/18/21, 10:20 AM

RF and material characterization for SRF films

The microscopic origins of Superconducting Radio Frequency (SRF) cavity breakdown by surface defects are still not completely understood. To locally study the electrodynamics of superconductors, a near-field magnetic microwave microscope was built. We study the 3rd harmonic response as a function of rf field amplitude and temperature. In previous experiments on Nb, two different types of...

13. DC magnetic field penetration results for Nb thin films with superconducting radiofrequency applications

Daniel Turner (Cockcroft Institute/Lancaster University)

3/18/21, 10:40 AM

RF and material characterization for SRF films

The material of choice for current SRF accelerators is bulk Nb which is reaching the theoretical limits in terms of maximum accelerating gradient, Eacc. One method to increase Eacc is to use superconductor-insulator-superconductor, SIS, structures, where the thin films on the surface are smaller than the London penetration depth to screen the applied field, Happ, such that the thicker...

30. Measurement system for lambda of thin-film sample at Kyoto University

Yoshihisa Iwashita (Kyoto University)

RF and material characterization for SRF films

Measurement system for lambda of thin-film sample at Kyoto University