Design of a Cloverleaf-Racetrack Dipole Demonstrator Magnet With Dual ReBCO Conductor

Abstract

For future 20+ T accelerator type magnets, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Re</i> BCO superconductors are ideal for their high current density in high magnetic field. At CERN, demonstrator dipole magnets using <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Re</i> BCO conductor are being developed in order to study their feasibility. In this work, a design of a cloverleaf-racetrack magnet is presented, which consist of two poles. A key problem in such magnets is how to realize the coil-ends without causing degradation due to coil winding, cool down and operation. The cloverleaf geometry accommodates the particle beam pipe without any hard-way <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Re</i> BCO tape bending. To design such geometry of the coil-end, a new method using Bézier splines is presented. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Re</i> BCO coils are wound with dual tape conductor where the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Re</i> BCO layers are facing each other. For quench protection, the coils are non-insulated, allowing the coil current at quench to redistribute transversally through the winding pack. A comparison between dry-wound and soldered non-insulated coils is made. Progress on the electromagnetic and mechanical design of the cloverleaf magnet is reported in this paper.