The XHV requirements for current and future light sources
Middleman, Keith; Herbert, Joe; Weston, Tom; Malyshev, Oleg; Jones, Lee United Kingdom
The Energy Recovery Linac Prototype (ERLP) is a new accelerator being built at Daresbury Laboratory that will demonstrate the process of energy recovery by the autumn of 2007. The project is a research facility to develop the technology required to build a 4th Generation Light Source (4GLS). These new facilities will use technologies that are new to our domain such as superconducting RF technology, photocathode materials and controlled clean room environments. The vacuum science group of ASTeC is directly responsible for the design of the vacuum systems in these key areas and for studying what influence the vacuum system can have on performance. This paper details the results of studies at Daresbury on the influence of vacuum on the performance of GaAs photocathodes showing the requirement for a controlled vacuum environment in order to achieve Quantum Efficiencies suitable for operation of ERLP. The paper will also detail the clean room techniques employed and the results of how particles are generated when handling vacuum equipment. This paper will also highlight how bakeout procedural changes can affect the vacuum environment in an XHV system, as well as the measurement limitations that exist with current vacuum equipment and how they have been overcome for the successful operation of an accelerator.