Abstract
Main features and key issues of the vacuum system for large-scale particle accelerators are presented, taking the KEKB vacuum system as an example. Other than its large scale and complexity, a distinctive difference of the accelerator vacuum system from other vacuum systems is the presence of high-energy charged-particle beams in the vacuum chamber (beam pipe). This brings troublesome but interesting problems into the system, such as the gas desorption by the synchrotron radiation from beams, the electro-magnetic interaction between beams and vacuum components and the interaction between beams and electrons or ions. These problems are more obvious on the KEKB vacuum system due to the unprecedented high stored beam current. The vacuum system will become increasingly important in future high-performance accelerators.
