Design of All-Superconducting User Magnets for EMFL

The magnetic field is an outstanding experimental tool for physics. To go beyond the conventional commercially available superconducting (SC) magnets, very large infrastructures such as the ones gathered within the European Magnetic Field Laboratory (EMFL) are necessary. The SuperEMFL project is a design study aiming at providing the European high field user community with much higher superconducting fields. This is meant to be achieved by combining high temperature superconductor (HTS) insert magnets, an emerging technology that can work in fields above 25 T, with low temperature superconductor (LTS) outsert magnets, a technology limited to fields below 25 T. The project has two design magnetic field targets, 32+T and 40+T. The first design target proposed to combined a single stack of HTS pancakes in combination with a 19 T / 150 mm LTS magnet; the second either a similar arrangement at the sake of a narrower central space or a design with two nested HTS coils combined with a 15 T/ 250 mm LTS magnet. The particular choice of the project is to use no insulation but a metallic tape co-wound with the bare HTS tape. This so-called Metal as Insulation (MI) technology enables a self-protection feature of the HTS coil by allowing the electrical bypass of defects as well as better mechanical performances in a very compact winding. The use of HTS inserts introduces a change of paradigm by providing an unprecedented combination of high magnetic field and long measurement times whilst saving vast amounts of energy in operation.