title: Analyses of the factors for the demagnetization of permanent magnets caused by high-energy electron irradiation.
abstract: 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.
authors.affiliation: XFEL/RIKEN, SPring-8, Sayo, Hyogo 679-5148, Japan. asano@spring8.or.jp
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Asano
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Bizen
authors.forename: Xavier
authors.initials: X
authors.lastname: Maréchal
mesh_terms: 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*