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Demagnetization of Nd-Fe-B Permanent Magnet at 2.5 GeV Electron Accelerator

Permanent magnets Nd2Fe14B are the main component of the insertion devices of the synchrotron radiation facilities and used at other accelerators. The radiation induced demagnetization of permanent magnets, becomes one of the most important issues of the next generation light sources. To investigate the radiation damage the magnetic field change of Nd2Fe14B magnet exposed to a 2.5 GeV electron beam has been measured. The radiation field near the magnet and the distribution of energy deposition in the magnet are studied with Monte Carlo code FLUKA. The radiation induced demagnetization is analyzed and a fitted formula is proposed to estimate the relative reduction of remanence.