Remagnetizing utilization of the radiation damaged wiggler

In this paper, a study of the radiation damage and re-magnetizing utilizati on of the permanent magnet wiggler used in the Beijing Free Electron Laser facility is reported. For the radiation damaged wiggler, the magnetic stren gth can be restored to the original value by magnet re-magnetization, arran gement optimization and re-assembly. The preliminary experimental result sh ows that the effective lifetime of the re-magnetized wiggler can be longer than the original wiggler under the same beam radiation condition. Also the mechanism of the magnet damage by radiation and the modification method ar e discussed.