Conveners
Superconducting Radio Frequency: Directions for R&D
- Sergey Belomestnykh
Superconducting Radio Frequency: Technology (i)
- Cristian Pira
Superconducting Radio Frequency: Technology (ii)
- Ursula Helga Van Rienen
Superconducting Radio Frequency: Technology (iii)
- Kellen McGee (Fermi National Accelerator Laboratory)
- Anne-Marie Valente-Feliciano
The FCC-ee must accommodate very different RF system requirements at different energy points driven by a fixed synchrotron radiation power budget of 100 MW. This talk presents the new baseline for the RF system implementation. The key update to the baseline scenario is a unification of the cavity designs for three beam energies (45.6, 80, and 120 GeV) due to the inclusion of the reverse phase...
The recent evolution of the FCC operational regime towards Reverse Phase Operation (RPO) for Z-pole has reduced by factor 2 RF power level required to feed individual cavities and put stringent requirements on the temporal RF power modulation of the two sets of accelerating SRF cavities in the collider. In this new environment, High Efficiency TS MBK Klystron, developed for FCC in the past few...
SRF R&D activities at INFN LNL cover all the cavity production chain with the main goal of producing the first prototype of a Nb3Sn on Cu 1.3 GHz elliptical cavity by the end of 2025. In particular INFN is focusing on Cu surface preparation by Plasma Electrolytic Polishing (PEP) and Nb3Sn coatings by DC Magnetron Sputtering.
Cu surface preparation by PEP presents several advantages over...
The SRF R&D project was launched in 2023, with the purpose to introduce a more detailed structure, coordination and progress reporting of the SRF R&D activity which is taking place since several years at CERN. More recently, the project was renamed as SRF R&D-R, to distinguish it from the twin SRF R&D-D, which is focused on producing demonstrators for the FCC. The overarching purpose of the...
The goal of FCCee, high energy and luminosity collisions, imposes technical challenges to the SRF cryomodules. To cope with high current e+/e- beams with relatively high accelerating gradients, one needs to achieve an extremely high-quality factor in accelerating mode while efficiently damping other modes. The former can be achieved by niobium cavities with dedicated heat treatment and the...
The development of cavity substrate for FCC involves a combination of activities aiming at both providing optimal substrates for superconducting coating studies and establishing a strategy for an industry-ready production of the full cavity series required by the FCC SRF scheme. The presentation will provide an overview of the status of these activities, which are ongoing at CERN,...
CERN now possesses both the tools and expertise required to electropolish 400 MHz copper elliptical cavities. This contribution provides a brief overview of the electropolishing setup, the associated interfaces, and the simulation efforts undertaken to design the system and optimize the process. A comparison between simulation data and results from actual processing will be presented and...
The Electron-Ion Collider (EIC) under construction at Brookhaven National Laboratory is being developed in partnership with the U.S. Department of Energyโs Thomas Jefferson National Accelerator Facility. The EIC will deliver high-luminosity, variable center-of-mass energy collisions of highly polarized electron beams with highly polarized proton beams and ion beams. Superconducting...
As part of a recently approved Accelerator R&D programme at CERN, we aim at building a new cryomodule demonstrator at 400 MHz: DEMO.
DEMO will be a full scale FCCee cryomodule housing four two-cell cavities of a novel design and operating at the RF parameters for the Reverse Phase Operation (RPO), the new RF baseline for FCCee to accelerate ee- beams at currents and energies spanning from...
This presentation will cover the latest status of the accelerating cavity designs for the FCC-ee main collider and booster, taking into account reverse phase operation. It will include the 2-cell 400 MHz cavities developed for the Z, W, H modes and part of the voltage needed for the ttฬ collider, as well as the 6-cell 800 MHz cavities designed for the ttฬ collider and booster. Each working...
Novel cooling schemes for SRF cavities are under study in the Cryolab at CERN aiming to improve cooling performance of the cavities in terms of heat transfer, lowering cooling source influences and improve cooldown behavior esp. at the transition temperature of the superconducting material. The studied options of integrated channel cooling are currently applied to 1.3 GHz coated copper...
The technical specifications for the cryomodules have been evolving following the SRF requirements and the approval of the Reverse Phase Operation (RPO) scheme. The conceptual design for the 400MHz and 800MHz cryomodules, as described in the FCC Feasibility Study Report, have been completed accounting for the SRF needs but also for the integration of the equipment and dedicated services in the...
800 MHz SRF cavity and cryomodule developments at FNAL towards FCC have been progressing through active and fruitful collaboration with CERN colleagues. With the recently published FCC Feasibility Study Report, the 800 MHz systems have changed from 5-cell to 6-cell bulk Nb cavities, and employ 112 cavities in 28 cryomodules for the booster up through the ZH operating point. At the ttb...
To address the challenges of helium and energy consumption in next-generation particle accelerators such as the Future Circular Collider (FCC), it is essential to reduce the demands placed on cryogenic infrastructure. This has spurred a growing interest within the scientific community in advancing technologies that support operation at temperatures above 2 K. Within this framework,...
The accelerating ramps of the high-energy booster are optimised to comply with the transverse beam size requirements at extraction energy while maintaining longitudinal beam stability. Specifically, the Z mode ramp includes an energy overshoot to boost the synchrotron radiation damping effect. Beam stability challenges are foreseen at low energy, which are mitigated with damping wigglers at...
The FCC-ee accelerating cavities need reliable power couplers to deliver high RF power across different operation modes. This presentation will cover the design of a 400 MHz coupler for the collider cavities, capable of delivering around 400 kW with a Qext adjustable between 9ร10โต and 5ร10โถ, for Z, W, H, and top-quark (ttฬ) operation. It will also present the design of an 800 MHz coupler for...
Niobium coated copper cavities proved their usefulness in several accelerators (e.g. LHC, HIE-ISOLDE). They allow operation at 4.5 K instead of 1.9 K leading to significant increase in the efficiency of cryogenic cooling. The main limitation of these cavities have been the significant Q-slope (the degradation of quality factor with increasing accelerating gradient). Another difficulty is...
Nb3Sn thin films are a promising candidate for use in superconducting radio frequency (SRF) cavities in order to achieve higher operating temperatures and reduced surface resistances.
Thin film with A15 phase can be manufactured e.g. by chemical vapor diffusion or DC magnetron sputtering.
In this work within the FCC Study, we present TEM, SEM and FIB investigations performed on thin Nb3Sn...
The SWELL and WOW cavities are novel superconducting RF (SRF) concepts developed within the framework of the FCC study, specifically designed for high beam current acceleration and deflection. Exploiting niobium thin film technology on copper substrates, these cavities offer significant advantages in terms of cost efficiency and performance robustness. This presentation summarizes preliminary...
