Sensitivity estimation for beam position monitors using a boundary element method

Abstract

BackgroundTo measure the beam positions of High Energy Photon Source (HEPS), different types of beam position monitors (BPMs) have been developed. The position sensitivity coefficient is an important parameter of BPMs by which the position of the beam can be calculated.PurposeThis study aims to establish a method for calculating the position sensitivity coefficient of BPMs.MethodsThe position sensitivity coefficients of various types of BPMs, such as round, elliptical, and octagonal pipes, were determined by using the boundary element method (BEM). The azimuth button angles in the elliptical BPM of the HEPS booster and the button distances in an octagonal BPM on the Beijing Electron Positron Collider II (BEPCII) storage ring were derivated by the application of BEM. Furthermore, the position sensitivity mappings of the BPMs was calculated.ResultsThe difference in sensitivity results of the round BPM calculated by the BEM and the analytical value is approximately 1%. The error between the calculated and experimental measurement results of the position sensitivity coefficients of the elliptical and octagonal sections is approximately 2%.ConclusionsThe BEM is a reliable method for calculating the position sensitivity coefficient of BPMs, which can be used in BPM design.

Keywords

• boundary element method
• beam position monitor
• position sensitivity coefficient
• high energy photon source