Configuration, optics, and performance of a 7-GEV Energy Recovery Linac upgrade for the advanced photon source

The Advanced Photon Source (APS) is a 7-GeV storage ring light source that has been in operation for over a decade. In order to make revolutionary improvements in the performance of the existing APS ring, we are exploring the addition of a 7-GeV energy recovery linac (ERL) [1] to the APS complex. In this paper, we show the possible configuration of such a system, taking into account details of the APS site and the requirement that stored beam capability be preserved. We exhibit a possible configuration for the single-pass, 7-GeV linac. We discuss optical solutions for transport from 10 MeV to 7 GeV and back, including a large turn-around are that would support 48 additional user beamlines. Tracking results are shown that include incoherent and coherent synchrotron radiation, resulting in predictions of the beamline performance. We also demonstrate the desirability of operation at high beam energy.