Studies On The Optimum Beam Orbit Correction For High Energy Electron Linacs

Obtaining a high quality beam bears on many factors at the exit of a high energy electron linear accelerator (Linac), beam orbit effect is one of the most important factors. The beam orbit offset effects caused by the initial beam offset and linac componets' offsets in beam transferring process. A high quality beam has low emittance and low energy dispersion. In order to obtain a high quality beam at the exit of a Linac, seriously controlling on the beam orbit in the linac is greatly important.In this paper, the beam orbit theory and possible offset effects described first. Secondly, the beam orbit offset effects caused by the initial beam offset and the linac components' offsets have been quantitatively studied first. As an example with the injector linac for Beijing Electron Positron Collider upgrading project (BEPCII), the beam orbit offset caused by the above error effects have been simulated and analyzed. Then, the beam orbit correction in BEPCII Lianc is simulated by optimum LIAR program and a design study on the optimum orbit correction system for BEPCII Linac is discussed. The optimum corrector's distribution and the required tolerances of misalignment of the linac components are given.