An Evaluation of the Helical Winding Method Applied to the Next European Dipole Project

The Next European Dipole (NED) Collaboration is working to develop the technology of high field, dipole magnets for a future luminosity upgrade of the LHC at CERN. The challenge is to design and build a short prototype, large aperture (88 mm), dipole magnet to operate at 15 T using conductors. While the baseline design uses a cosine- winding configuration, a key part of the NED program has been the evaluation of other winding configurations. This paper reports on an evaluation of the helical dipole winding method and its applicability to the high field, large aperture magnets required for NED. The paper describes the development of magnetic models using the OPERA3D code. These models have been used to assess the field homogeneity, peak field performance, forces and conductor efficiency of the helical winding. The parameters developed from this analysis are compared with cosine- models. A conceptual winding geometry is presented and evaluated.