Analyses of the factors for the demagnetization of permanent magnets caused by high-energy electron irradiation.
Demagnetization owing to high-energy electron irradiation has been analyzed for permanent magnets used in insertion devices of synchrotron radiation sources, using the Monte Carlo code FLUKA. The experimental data of a thermally treated Nd(2)Fe(14)B permanent magnet with a copper or a tantalum block at electron energies ranging from 2 to 8 GeV were compared with the calculation data of the absorbed doses, photoneutron production distributions and star densities. The results indicate that low-energy photoneutrons and bremsstrahlung photons are not involved in the demagnetization process, and suggest that the star density owing to the photoneutrons is strongly correlated with the demagnetization process.
Asano
Yoshihiro
Y
XFEL/RIKEN, SPring-8, Sayo, Hyogo 679-5148, Japan. asano@spring8.or.jp
Bizen
Teruhiko
T
Maréchal
Xavier
X
D003198:Computer Simulation; D017076:Computer-Aided Design; D004583:Electrons; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008280:Magnetics / Q000295:instrumentation*; D015233:Models, Statistical; D009010:Monte Carlo Method; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017356:Synchrotrons / Q000295:instrumentation*