等梯度加速结构中的尾场计算研究(英文)

Wake Field Calculation Studies in Constant Gradient Accelerating Structures

带电粒子束在穿过加速结构时激起的尾场,会导致束流能散和发射度的增大．准确计算尾场对正确估计尾场效应对束流性能的影响具有重要意义．本文对等梯度加速结构中短程尾场、中长程尾场和超长程尾场的计算方法进行了较系统的研究,并首次给出了超长程尾场的计算公式．此外,本文还给出了BEPCⅡ直线加速器等梯度加速结构中短程尾场、中长程尾场以及超长程尾场的计算结果,并对多种方法计算结果的一致性和在某些范围内的差别做了分析说明．

When charged particle beams traverse in an accelerating structure, the excited wake fields may dilute the beam energy spread and emittance. In order to estimate the wake field effects on the beam dynamics properly, it is very important to calculate the wake fields precisely. In this paper, the calculation methods of the short range, middle long range and super long range wake fields in constant gradient structures are systematically studied, and the expression of the super long range longitudinal wake field is first given. In addition, the wake fields for the BEPCⅡ Linac＇s disk-loaded structures are calculated by using analytical methods and various computer codes, the consistency and some deviations of the results obtained by different calculation methods are also discussed.