Numerical Calculations of the Magnetic Field of Bent Dipole Magnets

The high-energy storage ring (HESR) to be established as a part of the future facility for antiproton and ion research (FAIR) at gesellschaft fur schwerionenforschung (GSI) in Darmstadt (Germany) will be dedicated to studies with antiprotons in the momentum range from 1.5 GeV/c to 15 GeV/c. It will comprise 32 superconducting dipole magnets based on the RHIC DO design, yet with a radius of curvature of 15.279 m. The introduction of a finite radius is motivated by considerations both of field homogeneity along the particle path and available space for the HESR. On the other hand field distortions arise due to the curvature, which may compromise the advantage of the improved exploitation of the good-field region. This detrimental effect on our magnets has been quantified in this publication.