一种高重频废束桶束窗的设计及热结构分析

深圳中能高重频X射线自由电子激光（S3FEL）将建设成为全球唯一软X射线波段的高重频自由电子激光。废束桶是S3FEL装置的重要设备，在系统调束中发挥着重要作用。废束桶束窗是废束桶的重要组成部件，用于隔离和保护加速器超高真空环境。本文对几种常用的废束桶束窗材料进行了对比分析，最终选择铍作为束窗的材料，并依此设计了一种带有水冷结构的束窗。通过蒙特卡罗方法计算得到不同厚度束窗的沉积功率，采用有限元分析方法对不同厚度的束窗进行热结构计算与分析，得到厚度为1.6 mm的水冷铍窗效果最佳，其最大温度为121.6℃，低真空为1 Pa时的最大应力与中心变形分别为198.7 MPa和0.000 82 mm，低真空为101 325 Pa时的最大应力与中心变形分别为204.2 MPa和0.097 mm，结果均满足使用要求。此研究为S3FEL的废束桶束窗设计提供了重要的理论依据。

Design and thermal structure analysis of a dump beam window for high repetition frequency

Shenzhen Superconducting Soft X-ray Free Electron Laser (S3FEL) will be the only high refrequency free electron laser in soft X-ray band in the world. Dump, playing an important role in system beam tuning, is an important equipment of S3FEL device. As an important component of dump, dump beam window is used to isolate and protect the ultra-high vacuum environment of the accelerator. In this paper, several commonly used materials for dump beam window are compared and analyzed, beryllium is finally chosen as the material. A dump beam window with water-cooled structure is designed using to beryllium. The deposition power of beam window with different thickness is calculated by Monte Carlo method. The thermal-mechanical simulations based on the finite element analysis method show that the water-cooled beryllium window with a thickness of 1.6 mm is the best and meet the application requirements. Its maximum temperature is 121.6 ℃. The maximum stress and central deformation at low vacuum of 1 Pa are 198.7 MPa and 0.000 82 mm respectively. The maximum stress and central deformation at low vacuum of 101 325 Pa are 204.2 MPa and 0.097 mm respectively. The present study provides a critical theoretical basis for the design of dump beam window in S3FEL.