Study of some options for the CLIC final focusing quadrupole

This paper describes a feasibility study and the preliminary design for the CLIC final focusing quadrupoles. A possible design for a quadrupole consisting of rare-earth permanent magnet material is introduced. Due to its radiation hardness and its high remanence, Sm2Co17 seems to be the best suited permanent magnet material. The very high field gradients of 450 T/m can be achieved if pre-magnetized sectors made of permanent magnet material are assembled in ”zero clearance” design. An alternative solution with small superconducting coils is presented and briefly discussed, but would need further investigations.