• A.H. Lumpkin, W. Berg, M. Borland, N. Sereno
  ANL, Argonne, Illinois

Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

The interest in bunch compression to generate higher peak current electron beams with low emittance continues in the free-electron laser (FEL) community. At the Advanced Photon source (APS) we have both an rf thermionic gun and an rf photocathode (PC) gun on the S-band linac. At the 150-MeV point in the linac, we have a flexible chicane bunch compressor whose four dipoles bend the beam in the horizontal plane. There is also a vertical bend dipole after the chicane that allows measurement of energy and horizontal beam size at the imaging screen station to study possible effects on emittance due to coherent synchrotron radiation (CSR) in the chicane. A far-infrared (FIR) coherent radiation monitor is located downstream of the chicane as well. We have begun recommissioning of this device with coherent transition radiation (CTR), but we also have directly observed CSR from the bunch-compressed beam as it transits the vertical dipole and goes into the down leg. The unique geometry allows simultaneous tracking of bunch length, horizontal emittance, and energy distribution effects. Initial measurements of the CSR and CTR as a function of linac phase are described.