The Advanced Photon Source low-energy undulator test line

There are a number of fully commissioned 3rd-generation synchrotron light sources in the world today. So far they have met the demanding requirements of the user community; however, there is always a desire to go beyond what is presently available or even desirable. The Advanced Photon Source (APS) Low-Energy Undulator Test Line (LEUTL) was conceived to address the advancement of synchrotron light sources. The LEUTL uses the existing APS linac and a low-emittance electron gun, and by means of measurements of the beam and generated light, will test new and innovative undulators and push the technology and physics of single-pass, coherent light sources. The design and status of the LEUTL are described along with its immediate capabilities and those planned for the future.