Round Coil Superferric Magnet - Design and Test Results of the First MgB2 Accelerator Magnet

• Riccardo Umberto Valente - riccardo.valente@mi.infn.it (LASA)

Room: ZOOM Abstract: In the framework of the High Luminosity LHC program, the LASA Laboratory (INFN, Milan) collaborated with CERN to construct and test six different types of High Order corrector superconducting magnets NbTi-based. Besides the conventional design of these superferric magnets with Low-Temperature Superconductors (LTS), the Magnet Group of LASA also developed a novel and innovative alternative, a magnet in MgB2, which, with a high critical temperature (~39 K), opens interesting scenarios for Accelerator Physics applications. The seminar aims to present the innovative Round Coil Superferric Magnet (RCSM) design developed at LASA, based on an idea of I. F. Malyshev and V. Kashikhin, and re-proposed by G.Volpini. An arbitrary multipolar field can be produced by shaping the iron yoke properly and exciting a single large round coil (diameter > 100 mm), making the design particularly suitable for strain-sensitive materials like MgB2. Moreover, the RCSM can be assembled in a modular configuration simplifying the construction process, where a complete module consists of an even number of coils to cancel out the solenoidal field component completely. The Magnet Group at LASA fabricated and tested a RCSM in sextupolar configuration, assembled with two MgB2 round coils. The magnet has been tested at its operating current of 149 A, which corresponds to 40% of the margin on the load line at 4.2 K. Moreover, the magnet performance has been pushed to the maximum current, exploring the limit of the design and the technology eventually. In this talk, the test results will be presented, and the lessons learned will be discussed, in order to share the experience made in this first MgB2 application for accelerator magnets.