Design of a Sm/Co Magnetic Circuit for $S$ -Band 2.6-MW Magnetrons

In order to meet the need of miniaturization and long-term magnetic field stability of a permanent magnet system for the S-band 2.6-MW magnetrons, we propose to replace AlNiCo magnets with samarium cobalt ones as to reduce the volume and to improve the long-term stability of the magnetic system. The simulation design and parameter optimization of the samarium cobalt (Sm2/Co17) permanent magnet system including magnetic pole pieces were carried out, and then the magnetic system was fabricated and tested. The simulation results of radial, angular, and axial magnetic field distributions in the interaction space are found to be in good agreement with those of the test. Both the simulation and testing show that the samarium cobalt magnetic system is able to realize uniform radial, angular, and axial magnetic field distributions to meet the requirements of the magnetron. This paper demonstrates that it is feasible to replace the AlNiCo magnetic system with the samarium cobalt ones to achieve miniaturization and long-term magnetic stability of the magnetic system for the 2.6-MW magnetron. The volume and weight of the magnetic system are reduced by 79% and 64%, respectively, and it has been applied in linear accelerators system.