Measurement of permanent magnet material demagnetization due to irradiation by high energy electrons

Demagnetization of NdFeB permanent magnet (PM) samples delivered by the Stanford magnets company, has been measured as a function of radiation dose induced by high energy electrons. The 5 GeV electron beam from 12 GeV Cornell synchrotron was used as a radiation source. Calorimetric technique was employed for radiation dose measurement. Experimental data demonstrated strong correlation between susceptibility to demagnetization induced by radiation and temperature. The correlation was described by an exponential function with two parameters acquired from the data fitting. The obtained results will be used for evaluation of ERL IDs performance degradation rate under expected operation conditions. Experimental setup, measurement technique, results, analysis and conclusions are described.