• M. Borland, V. Sajaev
  ANL, Argonne

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
An Energy Recovery Linac (ERL) is one possibility for an upgrade to the Advanced Photon Source (APS). In addition to the linac itself, our concept involves a large turn-around arc (TAA) at 7 GeV that would eventually accommodate many new beamlines. Previously, we based the TAA design on isochronous triple-bend archromat (TBA) cells, since these are expected to provide some immunity to the effects of coherent synchrotron radiation. In the present work, we compare the previous TBA-based design to a new design based on double-bend achromat cells, in terms of emittance growth, energy spread growth, and energy recovery. We also explore the trade-off between optimization of the beta functions in the straight sections and minimization of emittance growth.

• V. Sajaev, M. Borland
  ANL, Argonne

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
One of the possible options for the Advanced Photon Source (APS) upgrade is an energy-recovery linac (ERL). In its main operating mode, the ERL bunch length would be two picoseconds. Even though this bunch length is already a factor of 20 shorter than the present APS bunch length, some experiments might require shorter X-ray pulses. For the APS storage ring, we plan to use an rf deflection technique* to generate one-picosecond X-ray pulses. In this approach, an rf cavity is used to deliver longitudinally dependent vertical kick to the electron beam and then a pair of slits is used to slice vertically streaked X-ray beam. We investigate the possibility and benefits of utilizing this technique to generate shorter X-ray pulses at the ERL.

*A. Zholents, et al., Nucl. Instr. and Meth. A 425 (1999) 385.

• V. Sajaev
  ANL, Argonne

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
An energy recovery linac (ERL) is one of the candidates for an upgrade of the Advanced Photon Source (APS). In addition to the APS ring and full-energy linac, our design also includes a large turn-around arc that could accommodate new X-ray beamlines as well. In total, the beam trajectory length would be close to 3 km. The ERL lattice has a strong focusing to limit emittance growth, and it includes strong sextupoles to keep beam energy spread under control and minimize beam losses. As in storage rings, trajectory errors in sextupoles will result in lattice perturbations that would affect delivered X-ray beam properties. In storage rings, the response matrix fit method is widely used to measure and correct linear lattice errors. Here, we explore the application of the method to the linear lattice correction of ERL.