Insulation Development for the Next European Dipole

Abstract

Electrical insulation is one of the most challenging issues governing the engineering exploitation of niobium-tin conductors. This is especially true for future accelerator magnets manufactured by the "wind-and-react" route. Applications such as the LHC Interaction Region upgrade or in the longer term an LHC energy upgrade will require magnets to operate at high fields in demanding thermal and radiation environments. The Next European Dipole (NED) programme is aimed at the development of a large aperture (up to 88mm) high field (up to 15T conductor peak field) superconducting dipole magnet relying on niobium-tin conductors. Conventional insulation development is being addressed in two key areas, the engineering requirements for large scale magnet manufacture and the improvement of materials properties for magnet operation and performance. The paper will review the status of insulation technology for niobium-tin accelerator magnets and define the special requirements for NED. Particular emphasis will be placed on the development of fibre sizing technology and its influence on magnet manufacture and electrical/mechanical performance of insulation laminates. This work is supported in part by the European Community ABSTRACTElectrical insulation is one of the most challenging issues governing the engineering exploitation of niobium-tin conductors. This is especially true for future accelerator magnets manufactured by the "wind-and-react" route. Applications such as the LHC Interaction Region upgrade or in the longer term an LHC energy upgrade will require magnets to operate at high fields in demanding thermal and radiation environments. The Next European Dipole (NED) programme is aimed at the development of a large aperture (up to 88mm) high field (up to 15T conductor peak field) superconducting dipole magnet relying on niobium-tin conductors. Conventional insulation development is being addressed in two key areas, the engineering requirements for large scale magnet manufacture and the improvement of materials properties for magnet operation and performance. The paper will review the status of insulation technology for niobium-tin accelerator magnets and define the special requirements for NED. Particular emphasis will be placed on the development of fibre sizing technology and its influence on magnet manufacture and electrical/mechanical performance of insulation laminates.

Upscaling of superfluid helium flow in porous media

“…Nb 3 Sn superconducting magnets must undergo a heat treatment at 700°C for several hours to actually create the Nb 3 Sn compound. New type of insulations, based on ceramic materials, is under development [10,11]. These ceramic materials have the advantage of surviving the heat treatment and creating porosity.…”

Braiding ultrathin layer for insulation of superconducting Rutherford cables

“…The cables are heat treated at high temperature (650°-700°C) 14, 23 for about 7 days 14 . The heat treatment is carried out in vacuum or in presence of an inert gas 24 (argon) to avoid oxidation of the cable surface 23 .…”

Experimental investigation of heat transfer through porous media in superfluid helium

“…The superconducting coil cooling is mainly controlled by conductive heat transfer and Kapitza resistance [3][4][5][6]. To enhance the heat transfer, new type of insulations based on ceramic materials were developed [7]. The advantage of these ceramic materials is to resist to the heat treatment and to create porosity allowing superfluid helium, which has almost no viscosity, to penetrate the insulation.…”