Collective effects analysis for the Berkeley Femtosource

We present an overview of collective effects in a proposed ultrafast X-ray facility, based on a recirculating linac. The facility requires a small vertical emittance of 0.4 mm-mrad and is designed to operate with a "flat bunch" with a large emittance ratio. Emittance control from the electron source at the RF photocathode to the photon production chain of undulators, including understanding and mitigation of collective effects, is critical to successful machine operation. Key aspects of accelerator physics involved in beam break-up, coherent synchrotron radiation, resistive wall impedance and other effects have been addressed and reported here.