论文标题
冷冻和真空系统
Cryopumping and Vacuum Systems
论文作者
论文摘要
对在低温温度下运行的复杂和/或大型真空系统的理解需要在这种温度下对真空科学的特定知识。在室温下，没有泵送与表面的低结合能的分子。但是，在低温温度下，由于温度降低，它们的逗留时间显着增加，这允许“冷冻倾斜”。该讲座介绍了低温真空领域，讨论表面解吸，粘附概率，热蒸腾，吸附等温线，常规气体的蒸气压，工业表面和粗糙度因子。这些方面用大型硬核对撞机的情况说明了其束屏幕，以及在低温环境中进行的冷冻，泄漏和梁真空系统建模。最后，讨论了针对LHC和其他低温机器的低温束真空系统的运行。
The understanding of complex and/or large vacuum systems operating at cryogenic temperatures requires a specific knowledge of the vacuum science at such temperatures. At room temperature, molecules with a low binding energy to a surface are not pumped. However, at cryogenic temperatures, their sojourn time is significantly increased, thanks to the temperature reduction, which allow a "cryopumping". This lecture gives an introduction to the field of cryogenic vacuum, discussing surface desorption, sticking probability, thermal transpiration, adsorption isotherms, vapour pressure of usual gases, industrial surfaces and roughness factors. These aspects are illustrated with the case of the Large Hardon Collider explaining its beam screen and its cryosorber, leaks and beam vacuum system modelling in a cryogenic environment. Finally, operation of cryogenic beam vacuum systems is discussed for LHC and other cryogenic machines.
