APS INSERTION DEVICES - RECENT DEVELOPMENTS AND RESULTS

The Advanced Photon Source (APS) now has a total of 23 insertion devic es (IDs). Over two-thirds of them are installed on the storage ring. T he installed devices include 18, 27 and 55 mm-period undulators; an 85 mm-period wiggler; a 16 cm-period elliptical multipole wiggler; and m any 33 mm-period undulators. Most of the IDs occupy storage-ring strai ght sections equipped with 8 mm vertical-aperture vacuum chambers. All of the IDs were measured magnetically at the APS and, in most cases, underwent a final magnetic tuning in order to minimize variation in th e various integrals of the field through the ID over the full gap rang e. Special shimming techniques to correct magnetic field parameters in appropriate gap-dependent ways were developed and applied. Measuremen ts of the closed-orbit distortion as a function of the ID gap variatio n have been completed, and results are in a good agreement with magnet ic measurements. Spectral diagnostics of the ID radiation, including m easurements of the absolute spectral flux, brilliance and polarization , show excellent agreement between calculated and measured results. St udies of the sensitivity of IDs to radiation exposure and measurements of the dose rate received by the IDs are in progress.