Speaker
Description
The new Future Circular Colliders (FCC), including high-luminosity e⁺e⁻ collider, exploits the crab waist interaction scheme at interaction region (IR) with a beam crossing angle of 30 mrad. The small values of the beta functions at the interaction point requires strong and thin crab sextupole pair for chromaticity correction. Their location between 250 m and 700 m from the interaction region, makes helium bath cooling impractical and dry conduction-cooled sextupole magnet could be an attractive alternative.
For the energy sawtooth and energy scan scenario beyond 182.5 GeV, the required maximum sextupole magnet bore field is 4.72 T at 35 mm radius or a strength of 3850 T/m2 over a magnetic length of 350 mm. Low and high temperature superconductor (LTS and HTS) magnets are viable potential options for such operating field.
The HTS option, operating at 10-20 K, requires a simpler conduction cooling setup, and lower power than LTS, operating at around 4 K. Over the last decade, HTS ReBCO coated tape conductors (CC) benefited from substantial price to performance and long lengths availability improvements. Therefore, they are increasingly attractive for building the next generation of energy-efficient high-field magnets that are conduction cooled.
The alternative design options of construction of the cryogen-free conduction-cooled IR crab sextupole will be presented. The preliminary design focuses on the magnetic cross section optimisation for both LTF and HTS conductors and the proposed mechanical structure based on ReBCO tape racetrack winding. A first coil quench protection scheme is proposed and assessed as function of the winding manufacture choices.
Index Terms— ReBCO, HTS, cryogen-free conduction cooling, cryocooler-cooled superconducting magnet, high magnetic field, reinforced racetrack coil.
