Materials and Surface Aspects in the Development of SRF Niobium Cavities

Vol. XII, Editorial Series on Accelerator Science (R.S. Romaniuk, J.-P. Koutchouk - Editors) 
 
For more information see page eucard-old.web.cern.ch/eucard-old/activities/communication/booklets/
 
Słowa kluczowe: materiały nadprzewodzące dla techniki akceleratorowej, niod nadprzewodzący, technologia powierzchni niobu, inżynieria materiałowa niobu nadprzewodzącego, wnęki niobowe
 

Keywords: superconducting materials for accelerator technology, superconducting niobium, technology of niobium surface, material engineering of superconducting niobium, niobium cavities
 

Abstract:

In last two decades the SRF community reached immense progress in technology of fabrication and preparation of superconducting resonators. For example beginning of nineties the required accelerating gradient of 15 MV/m for 1.3 GHz 9-cell cavities for Tesla Test Facility was considered as an ambitious aim. Nowadays gradients of 45 MV/m are demonstrated on such ENGINE of cavities. All this achievements have been reached thanks to improvements in our understanding of many technological and fundamental aspects: e.g. procedures of material production from ore to niobium semi-finished product, material diagnostic, cavity fabrication procedure in particular the features of the electron beam welding, preparation procedures in particular of the surface contamination and cleanness items etc. New techniques and procedures have been developed and many of them applied in the meantime for cavity serial production, for example for European XFEL: eddy current scanning, surface treatment by electropolishing, ethanol rinsing, baking at 120°C. Good progress is achieved in fabrication of large grain cavities, weld-less fabrication by hydroforming or spinning, dry ice cleaning etc. The most of mentioned aspects of innovative techniques are described and analyzed in the book presented to the readers.