Mechanical design of a flexible bunch compressor for APS linac

A bunch compressor has been installed in the APS linac to produce high peak currents for the FEL project and to explore the effects of coherent synchrotron radiation (CSR). The bunch compressor design is based on an asymmetric four-dipole chicane configuration in which asymmetry and variable R₅₆ can be optimized to control CSR-induced emittance growth. This flexibility is achieved by allowing the middle two dipoles to move transversely to the beam and the last dipole to move longitudinally. In this paper we describe the design of the stages used for precise movement of the bunch compressor magnets and associated diagnostics components