For the design of high-performance particle accelerators and vacuum systems for high-energy colliders, the choice of materials and of their surface treatment is an essential prerequisite. Physical and optical properties of such materials and their coatings are input parameters for programs to simulate their performance and to validate machine design. Materials behavior after exposure to synchrotron radiation (SR), produced by the circulating particles, need to be studied because of its detrimental consequences, such as photo induced desorption, heat load, vacuum and beam induced instabilities. Reflectivity, its angular distribution and photo yield, i.e., the number of photoelectrons produced per incident photon, are essential ingredients to simulation codes. Such parameters must be studied not only on materials as they are in accelerators, but also in conditions as close as possible to the operative ones. In this work, we present results of such an experimental campaign, carried out at the Optics Beamline of BESSY-II. This experimental setup, designed to investigate quasiperfect x-ray-optical elements by “at-wavelength” metrology (from 35 eV to 1850 eV), is also an ideal tool to perform reflectivity and photo yield studies of vacuum chamber materials. As will be discussed, different roughness and various nano-, micro- or macro- modifications of a Cu-surface significantly influence the parameters under study. Energy- and angle-integrated values for the total reflectivity and photo yield are derived. Such integrated values are representative for material behavior under “white-light” irradiation for the various accelerators discussed here.

中文翻译：

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促进剂中铜的反射率和光电子产率

对于设计用于高能对撞机的高性能粒子加速器和真空系统，选择材料及其表面处理是必不可少的先决条件。此类材料及其涂层的物理和光学特性是程序的输入参数，以模拟它们的性能并验证机器设计。由于循环粒子产生的有害后果，例如光致脱附，热负荷，真空和束流引起的不稳定性，因此需要研究循环粒子产生的暴露于同步加速器辐射（SR）后的材料性能。反射率，其角度分布和光产率（即每个入射光子产生的光电子数）是模拟代码的基本要素。不仅必须像加速器中的材料一样研究这些参数，而且还要在尽可能接近手术条件的条件下进行。在这项工作中，我们介绍了在BESSY-II的“光学光束线”上进行的此类实验活动的结果。这种实验装置旨在通过“波长”度量（从35 eV到1850 eV）研究准完美的X射线光学元件，也是进行真空室材料的反射率和光良率研究的理想工具。如将要讨论的，Cu表面的不同粗糙度和各种纳米，微观或宏观修饰会显着影响所研究的参数。得出了总反射率和光产出的能量和角度积分值。这样的积分值代表了此处讨论的各种促进剂在“白光”照射下的材料行为。