The Einstein Telescope (ET) is a project aiming to realize a facility to host a gravitational wave (GW) detector of the third generation. The new instrument will change our vision of the Universe by observing millions of GW signals emitted during the coalescence of stellar and intermediate-mass black hole binary systems. It will permit to shed light on the first phase of the Universe formation and it will contribute to solving the dark matter enigma. The new GW detector is conceived as a series of six nested Michelson interferometers forming a triangle of 10 km side. The laser light biasing the interferometers must propagate in large ultra-high vacuum (UHV) tubes in order to reduce the noise induced by the residual gas pressure fluctuations, setting a requirement on the residual pressure in the ${10}^{-10}$ mbar range. The vacuum system will be made of a pipe with a 1 m diameter and an overall length of 120 km, making ET one of the largest UHV systems ever made. The giant UHV project asks for attentive optimization of material choice, manufacturing processes, post-processing treatments of the tubes, and pumping systems in order to find a cost-effective solution. In this article, we shortly review the vacuum solution adopted in the case of the second generation of GW detectors. After a general description of the main elements that constitute the ET vacuum system, the detailed design being the subject of the next 3 years of work, we will present a refined calculation of the noise due to residual-gas pressure fluctuations in the ET beam pipe.

中文翻译：

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爱因斯坦望远镜项目超高真空束管：挑战与展望

爱因斯坦望远镜 (ET) 是一个旨在实现承载第三代引力波 (GW) 探测器的设施的项目。新仪器将通过观察恒星和中等质量黑洞双星系统合并期间发出的数百万 GW 信号来改变我们对宇宙的看法。它将揭示宇宙形成的第一阶段，并将有助于解决暗物质之谜。新的 GW 探测器被设想为一系列六个嵌套的迈克尔逊干涉仪，形成一个边长为 10 公里的三角形。偏置干涉仪的激光必须在大型超高真空 (UHV) 管中传播，以减少残余气体压力波动引起的噪声，从而对干涉仪中的残余压力提出要求${10}^{-10}$ 毫巴范围。真空系统将由直径为 1 米、总长度为 120 公里的管道制成，使 ET 成为有史以来最大的特高压系统之一。这个巨大的特高压项目要求对材料选择、制造工艺、管道后处理和泵送系统进行细心优化，以找到具有成本效益的解决方案。在本文中，我们简要回顾了第二代 GW 探测器采用的真空解决方案。在大致描述了构成 ET 真空系统的主要元件之后，详细设计是未来 3 年工作的主题，我们将对 ET 光束管中残余气体压力波动引起的噪声进行精细计算.