Field dependent surface resistance of niobium on copper cavities

Study of Ultra-clean Surface for Niobium SC Cavities

For a TeV energy particle physics, R&D of electron/positron linear colliders has been conducted very hard at many laboratories. Development of high field gradient cavities is one of key issues to realize such a machine. Field emission loading is a dominant phenomenon limiting high field. Particulate contamination on the inner surface is a main source of field emission. In this paper, we report ...

Surface Superconductivity in Niobium for Superconducting RF Cavities

A systematic study is presented on the superconductivity (sc) parameters of the ultrapure niobium used for the fabrication of the nine-cell 1.3 GHz cavities for the linear collider project TESLA. Cylindrical Nb samples have been subjected to the same surface treatments that are applied to the TESLA cavities: buffered chemical polishing (BCP), electrolytic polishing (EP), low-temperature bakeout...

3D Atom Probe Microscopy on Niobium for SRF Cavities

Fermi National Accelerator Laboratory (FNAL) is developing superconducting RF cavities for a future high-energy electron-positron linear collider as the next international, large-scale high energy physics discovery machine. Recently FNAL and the Northwestern University Center for Atom-Probe Tomography (NUCAPT), Evanston, Illinois, have joined forces to investigate the properties of the high pur...

Measurements at Slac on Superconducting Niobium Cavities and Structures

Tests are continuing at SLAC on superconducting niobium cavities and structures at Sand X-band frequencies. Peak electric and magnetic fields on the order of 20 MV/m and 400 G have been obtained in a TM mode cavity at 2.85 GHz with unloaded Q’s at high fields on the order of 1010. These fields and Q’s are adequate for superconducting RF systems for high energy storage rings and recirculating li...

Modeling, Fabrication, and Optimization of Niobium Cavities: Final Phase