Engineering limitations with electrons

The vacuum required for electron machines is determined by the beam lifetime and must be in the ultrahigh vacuum range. Since the emission of intense synchrotron radiation by the electron beam produces strong dynamic outgassing from the vacuum chamber, this gas load must be removed by a powerful, distributed pumping system. To achieve good beam lifetimes an extended in-situ cleaning (beam conditioning) by synchrotron radiation must be applied. High pumping speeds can be obtained using a distributed pumping system, e.g. based on linear, non-evaporable getter pumps. The absorption of the synchrotron radiation power, either by the vacuum chamber directly or on local aborbers,is closely linked to the design of the global system and to the choice of the vacuum chamber material.