Magnetic field correction based on intelligent shimming method

Abstract

An APPLE-II elliptically polarized undulator (EPU) is commonly used in third-generation electron accelerator storage ring to provide varied polarization soft X-ray. When electron beam passes through an undulator, the radiation is generated and collimated. In order to have high photon flux, these collimated photons need to be coherent. Therefore, prefect magnetic fields are necessary for electron beam trajectory and phase. EPU46 consists of 1,320 magnet blocks to create sinusoidal magnetic field, and four-phase modes generate various polarization on synchrotron soft X-ray. The objective functions are to minimized electron trajectory/angle deviation and phase error. Without intelligent optimization method, field correction becomes a tedious and time-consuming work. In this chapter, a field shimming adapted with Genetic Evolutionary algorithm is developed; the methodology and results are presented. © 2013 Springer Science+Business Media New York.