be had to refrigeration devices a system of at least six superconducting individual coils is provided of the six superconducting individual coils two at a time are embodied and disposed in pairs in mirror symmetry to the beam control plane 6 accordingly in terms of individual coils the system includes two elongated saddle shaped coils 8 and 9 hereinafter called primary coils these coils each have two curved side parts 8 a 8 b and 9 a 9 b respectively extending laterally of the beam control tube 5 as well as end parts 8 c 8 d and 9 c 9 d on the face ends the end parts on the face ends may be each bent or angled in such a way out of the plane defined by the side parts of the primary coil that they each extend semi circularly around the outside of the beam control tube 5 the shaping of corresponding primary coils is generally known see for example european patent disclosure ep 0 276 360 b1 optionally however still other known saddle shapes are suitable resting on a curved cylindrical jacket face in other words the side parts 8 a 8 b and 9 a 9 b need not each extend exactly.