Status of the APS diagnostics undulator beamline

Abstract

We report the status of the diagnostics undulator beamline for the Advanced Photon Source (APS) storage ring. The beamline was designed for the characterization of the 7-GeV, low-emittance positron beam at high resolution. The special diagnostics undulator has been manufactured by STI Optronics. The device exhibits very low magnetic field errors at closed gap of 10.5 mm: first field integral less than 15 gauss/spl middot/cm, and optical phase error less than 1.5/spl deg/. The front end of the beamline and a monochromator are installed and tested for use on divergence and directional stability measurements with a target resolution of 3 /spl mu/rad utilizing the first harmonic radiation of 25 keV. Initial results for the divergence measurement show that the storage ring is operating well within its design goals.