INFN/LNL, Legnaro (PD), Italy
CEA-IRFU, Gif-sur-Yvette, France
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
Cockcroft Institute, Warrington, Cheshire, United Kingdom
CEA-DRF-IRFU, France
Piccoli, Noale (VE), Italy
INFN/LASA, Segrate (MI), Italy
INFN- Sez. di Padova, Padova, Italy
The University of Liverpool, Liverpool, United Kingdom
Lancaster University, Lancaster, United Kingdom
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
University Siegen, Siegen, Germany
HZB, Berlin, Germany
University of Siegen, Siegen, Germany
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
Riga Technical University, Riga, Latvia
HZDR, Dresden, Germany
Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
IEE, Bratislava, Slovak Republic
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
JLab, Newport News, Virginia, USA
Thin-film cavities with higher Tc superconductors (SC) than Nb promise to move the operating temperature from 2 to 4.5 K with savings 3 orders of magnitude in cryogenic power consumption. Several European labs are coordinating their efforts to obtain a first 1.3 GHz cavity prototype through the I.FAST collaboration and other informal collaborations with CERN and DESY. R&D covers the entire production chain. In particular, new production techniques of seamless Copper and Niobium elliptical cavities via additive manufacturing are studied and evaluated. New acid-free polishing techniques to reduce surface roughness in a more sustainable way such as plasma electropolishing and metallographic polishing have been tested. Optimization of coating parameters of higher Tc SC than Nb (Nb₃Sn, V₃Si, NbTiN) via PVD and multilayer via ALD are on the way. Finally, rapid heat treatments such as Flash Lamp Annealing and Laser Annealing are used to avoid or reduce Cu diffusion in the SC film. The development and characterization of SC coatings is done on planar samples, 6 GHz cavities, choke cavities, QPR and 1.3 GHz cavities. This work presents the progress status of these coordinated efforts.
INFN/LNL, Legnaro (PD), Italy
INFN- Sez. di Padova, Padova, Italy
Rösler Italiana s.r.l., Concorezzo, Italy
In this study, Metal Additive Manufacturing (MAM) was evaluated as a viable method for producing seamless 6 GHz pure copper and niobium prototypes without the use of internal supports. Preliminary tests were performed to evaluate printability, leading to further investigations into surface treatments to reduce surface roughness from 35 µm to less than 1 µm. Additional prototypes were printed using different powders and machines, exploring various printing parameters and innovative contactless supporting structures to improve the quality of downward-facing surfaces with small inclination angles. These structures enabled the fabrication of seamless SRF cavities with a relative density greater than 99.8%. Quality testing was conducted using techniques such as tomography, leak testing, resonant frequency assessment, and internal inspection. The results of this study are presented herein.
