Lawrence Berkeley National Laboratory

CIRCE (Coherent InfraRed CEnter) at the Advanced Light Source, Lawrence Berkeley National Lab (LBNL), is a proposal for a new electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range. One of the main requirement for this special mode of operation is the capability of the ring of operating at small momentum compaction values. In this regime, the longitudinal dynamics becomes strongly nonlinear and an accurate control of the higher order energy dependent terms of the mumentum compaction is necessary. The lattice for CIRCE allows controlling the seterms up to the third order. The paper describes the lattice and presents the calculated performances in terms of momentum acceptance, dynamic aperture , lifetime and momentum compaction tune capabilities.