Coaxial multi-mode cavities for fundamental SRF research in an unprecedented parameter space
arXiv:2010.02192 · doi:10.1103/PhysRevAccelBeams.23.122001
Abstract
Recent developments in superconducting radio-frequency (SRF) research have focused primarily on high frequency elliptical cavities for electron accelerators. Advances have been made in both reducing RF surface resistance and pushing the readily achievable accelerating gradient by using novel SRF cavity treatments including surface processing, custom heat treatments, and flux expulsion. Despite the global demand for SRF based hadron accelerators, the advancement of TEM mode cavities has lagged behind. To address this, two purpose-built research cavities, one quarter-wave and one half-wave resonator, have been designed and built to allow characterization of TEM-mode cavities with standard and novel surface treatments. The cavities are intended as the TEM mode equivalent to the 1.3GHz single cell cavity, which is the essential tool for high frequency cavity research. Given their coaxial structure, the cavities allow testing at the fundamental mode and higher harmonics, giving unique insight into the role of RF frequency on fundamental loss mechanisms from intrinsic and extrinsic sources. In this paper, the cavities and testing infrastructure are described and the first performance measurements of both cavities are presented.
References in corpus (14)
- Nitrogen and argon doping of niobium for superconducting radio frequency cavities: a pathway to highly efficient accelerating structures
- Unprecedented Quality Factors at Accelerating Gradients up to 45 MV/m in Niobium Superconducting Resonators via Low Temperature Nitrogen Infusion
- Field-dependent nonlinear surface resistance and its optimization by surface nano-structuring in superconductors
- Flux expulsion in niobium superconducting radio-frequency cavities of different purity and essential contributions to the flux sensitivity
- Accelerating fields up to 49 MV/m in TESLA-shape superconducting RF niobium cavities via 75C vacuum bake
- The Role of Magnetic Flux Expulsion to Reach Q0>3x10^10 in SRF Cryomodules
- Comment on Field-dependent surface resistance for superconducting niobium accelerating cavities
- Field of first flux entry and pinning strength of superconductors for RF application measured with muon spin rotation
- Extension of the Measurement Capabilities of the Quadrupole Resonator
- Muon spin rotation studies of niobium for superconducting RF applications
- Fermilab experience of post-annealing losses in SRF niobium cavities due to furnace contamination and the ways to its mitigation: a pathway to processing simplification and quality factor improvement
- Improved RF Measurements of SRF Cavity Quality Factors
- Determination of the magnetic field dependence of the surface resistance of superconductors from cavity tests
- Achievement of Ultra-High Quality Factor in Prototype Cryomodule for LCLS-II