Magnet Design and Measurement Results of the Solenoids and Bunch Compressor Bending Magnets of the SwissFEL Test Facility

The SwissFEL Injector Test Facility at the Paul Scherrer Institute (PAI/Switzerland) started its operation in August 2010. This Facility represents the first stage of the 6 GeV acceleration complex foreseen for the SwissFEL X-Ray coherent light source planned at the PSI. The 250 MeV Injector consists of an S-Band RF photo injector followed by four S-Band acceleration structures of 4 m length each. For fine focusing corrections each accelerating structure is surrounded by four solenoids (WFS) of 0.8 m length and a maximum field of 0.1 T. Each solenoid consists of two coils in one yoke tube. To decrease the bunch length of the electron beam a magnetic bunch compressor chicane with four dipoles (AFBC2) providing a maximum magnetic field of 0.4 T for a length of 0.25 m was build. The central dipoles of the compressor chicane are sited on a movable girder to allow extensive compression studies with dipole angles between 0° and 5°. The preservation of a high brightness and a low emittance for the femto-second electron pulse impose severe tolerances in the field quality and in the magnet positioning. In this paper we review the design of two magnet types and discuss the results of field quality and magnetic axis measurements in terms of the specifications.