Evaluation of the possibility of upgrading the advanced photon source to an energy recovery linac

One of the concepts being explored for a next-generation X-ray source is the energy recovery linac (ERL). It is well known that, as a synchrotron radiation source matures, the value of the X-ray beamlines and experimental infrastructure approaches and then exceeds the value of the accelerator complex. Hence, it makes sense to think of eventually upgrading the advanced photon source (APS) to an ERL. We explore through simulation the potential performance that might be obtained by injecting an ERL beam into the APS and circulating one or more turns. Issues covered include lattice choices, coherent synchrotron radiation effects, and bunch lengthening. We also give a comparison of the expected brightness to that of the present APS.