Septum-magnet for the Main Extraction Line of the Tesla linear collider

The results of calculations and the. key design problems for the normal-conducting septum magnet for the Main Extraction Line of the TESLA linear collider are presented. The septum magnet is required to vertically deflect the so-called "spent beam" (after the interaction point) into the extraction line channel, while leaving the incoming (oppositely charged) beam undisturbed. The distance between the incoming beam and the copper septum is about 9 mm. The total length of the magnet core is 16 m. The 0.175 T magnetic field in 85 mm gap is produced by the copper winding and steel core. The septum is 5 mm thick. The stray field should not exceed 1 G. The septum-magnet should operate in the continuous regime. The required distribution of the magnetic field and the pole dimension of the septum-magnets have been calculated and optimized using two-dimensional models. A full-scale mock-up of one section of the septum-magnet has been developed and will be constructed for testing at the D.V. Efremov Scientific Research Institute of Electrophysical Apparatus.