An Improved Analysis of PPM Focusing Structures Including the Effect of Magnetic Saturation in the Iron Pole Pieces

摘要

In this paper, an improved analysis of the periodic permanent magnet (PPM) focusing structure for linear beam tubes is presented. An estimation of critical dimensions for the iron pole pieces to avoid magnetic saturation is made. The method is based on the permeance calculation of all possible flux paths using magnetic circuit theory. The analytically calculated axial magnetic field using the present approach is compared with measured and simulated results obtained by using the finite-element- method-based commercial software ANSYS. The agreement is very good.