A NEW 5BA LOW EMITTANCE LATTICE FOR SIRIUS

Sirius is a third-generation low emittance synchrotron light source under construction at LNLS, the Brazilian Synchrotron Light Laboratory. A new 5BA lattice was designed in replacement for the previous TBA lattice with the aim to reduce the emittance to sub-nm.rad values. The new design has a circumference of 518 m with 20 achromatic straight sections and a natural emittance of 0.28 nm.rad at 3 GeV for the bare lattice (without IDs). The dipoles combine low 0.58 T field magnets for the main beam deflection with a 2 T short superbend magnet sandwiched in the center dipole. This creates a longitudinal dipole gradient that is used both to lower the emittance and to provide hard X-ray dipole sources.