Radiation-induced magnetization reversal causing a large flux loss in undulator permanent magnets

Radiation-induced magnetization reversal causing a large flux loss in undulator permanent magnets

We report an unexpectedly large flux loss observed in permanent magnets in one of the undulators operated in SACLA, the x-ray free electron laser facility in Japan. Characterizations of individual magnets extracted from the relevant undulator have revealed that the flux loss was caused by a homogeneous magnetization reversal extending over a wide area, but not by demagnetization of individual m...

Magnetic reversal in Sm2Fe17Ny permanent magnets

Radiation-Induced Demagnetization of Nd-Fe-B Permanent Magnets

Introduction The Advanced Photon Source (APS), as well as other third-generation synchrotron light sources, uses permanent magnets in the insertion devices to produce x-rays for scientific research [1,2]. When placed in a high-energy storage ring, these permanent magnets are subjected to irradiation from synchrotron radiation, high-energy bremsstrahlung, and bremsstrahlung-produced neutrons. Pr...

First order reversal curve studies of permanent magnets

First order reversal curve (FORC) diagrams are a useful tool to analyze the magnetization processes in magnetic materials. FORC diagrams are computed from measured first order reversal curves on sintered Nd 2 Fe 14 B magnets. It is shown that the FORC diagram simplifies if the first order reversal curves a desheared using the macroscopic demagnetizing field given by the geometry of the sample. ...

Linear Transverse Flux Reluctance Machine with Permanent Magnets

A new structure of linear transverse flux machine (TFM) is presented in this paper. It is in fact a variable reluctance linear machine having permanent magnets on the mover. Its structure and its working principle will be discussed. After a preliminary design of the motor a 3D FEM analysis was carried out before optimizing the designed linear motor. The flux densities in the machine and the sta...