title: Online beam energy measurement of Beijing electron positron collider II linear accelerator.
abstract: This paper describes online beam energy measurement of Beijing Electron Positron Collider upgraded version II linear accelerator (linac) adequately. It presents the calculation formula, gives the error analysis in detail, discusses the realization in practice, and makes some verification. The method mentioned here measures the beam energy by acquiring the horizontal beam position with three beam position monitors (BPMs), which eliminates the effect of orbit fluctuation, and is much better than the one using the single BPM. The error analysis indicates that this online measurement has further potential usage such as a part of beam energy feedback system. The reliability of this method is also discussed and demonstrated in this paper.
authors.affiliation: Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.affiliation: Centre for High Energy Physics, University of the Punjab, Lahore 45590, Pakistan.
authors.forename: M
authors.initials: M
authors.lastname: Iqbal
authors.affiliation: Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: R
authors.initials: R
authors.lastname: Liu
authors.affiliation: Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Chi