The EuCARD-2 Future Magnets European Collaboration for Accelerator-Quality HTS Magnets

Abstract

Abstract-EuCARD-2 is a project supported by FP7-European Commission that includes, inter alia, a work-package (WP10) called "Future Magnets". This project is part of the long term development that CERN is launching to explore magnet technology at 16 T to 20 T dipole operating field, within the scope of a study on Future Circular Colliders. The EuCARD2 collaboration is closely liaising with similar programs for high field accelerator magnets in the USA and Japan. The main focus of EuCARD2 WP10 is the development of a 10 kA-class superconducting, high current density cable suitable for accelerator magnets, The cable will be used to wind a stand-alone magnet 500 mm long and with an aperture of 40 mm. This magnet should yield 5 T, when stand-alone, and will enable to reach a 15 to 18 T dipole field by placing it in a large bore background dipole of 12-15 T. REBCO based Roebel cables is the baseline. Various magnet configurations with HTS tapes are under investigation and also use of Bi-2212 round wire based cables is considered. The paper presents the structure of the collaboration and describes the main choices made in the first year of the program, which has a breadth of five to six years of which four are covered by the FP7 frame.

An equation for the quench propagation velocity valid for high field magnet use of REBCO coated conductors

“…[1][2][3][4] HTS are not subjected to stability issues as LTS, and can, in principle, be operated without any protection. 5 However, this is usually not the case for HTS magnets, whose protection against quenchinduced damages is motivated by their high cost.…”

Superconducting magnetic energy storage and superconducting self-supplied electromagnetic launcher

“…BOSSE project is part of a strong technological development around REBCO HTS tapes. It has a synergy with other projects such as very high field superconducting magnets (NOUGAT project) [22] or high field HTS dipole magnets considered for the future of the Large Hadron Collider in CERN (projects EUCARD et EUCARD-2) [10,30].…”

“…Even if cables with currents of several kA have been manufactured and tested under field [9,10], cables with currents in the range of hundreds of kA or more are not existing today. Another solution consists in using the SMES as a buffer power supply in order to quickly recharge a capacitor bank.…”

“…Copper is used as stabilizer but adds negligible mechanical reinforcement. Furthermore, the 1 MJ range leads to rather large inductances unless using multi-tape cables [9,10], which would add another layer of complexity and was not considered in this project. Such high inductance slows down the coil discharge.…”

Development of a Roebel-cable-based cos-theta dipole: design and windability of magnet ends

“…Indeed, Low Temperature Superconductors (LTS) such as Nb-Ti or Nb3Sn do not allow for generating magnetic fields larger than 15 T. Both technologies -LTS and HFS -must be coupled into one hybrid magnet where only its core, subjected to the highest field, would consist of HFS, the outer windings being made of LTS. Therefore, in the framework of two European Commission funded projects, namely EuCARD-WP7 [2] and EuCARD2-WP10 [3][4], application of HFS to accelerator magnet inserts has been developed. Progress about the EuCARD-WP7 HFS racetrack insert can be found in [5].…”