Design of a superferric dipole magnet with high field quality in the aperture

A project to design and construct a new international accelerator was proposed by GSI (Darmstadt, Germany). This project includes the design of several new facilities. One of them is a collector ring (CR). The magnets of the CR operate at constant field (DC), but the level of this field varies for different operational tasks. The magnet system of the CR includes 24 deflecting dipole magnets. The maximum operating field in the aperture is 1.6 T, with a deflection angle of 15 degree, and a bending radius of 8.125 m. The most important requirement for this dipole is a high field uniformity (better than ±0.01% over a volume of 380 mm × 150 mm). This requirement must be met for all levels of magnetic flux density in the aperture. Several magnet designs have been investigated including window frame and H-type versions with normal and superconducting coils. The best economical and technical parameters were obtained for a superferric H-type magnet with a wide air filter in the pole. The field homogeneity requirements were fulfilled in such a magnet for field range of 0.2-1.63 T. The effects of the field distortion in the end parts of the magnet, as well as influence of the end plates on the field quality, were also investigated.