LATTICE STUDIES FOR THE MAX-IV STORAGE RING

The lattice for the future MAX-IV storage rings at MAX-Lab has been studied. The MAX IV facility consists of two similar rings operated at 1.5 GeV and 3 GeV electron energies. The ring consists of 12 supercells each built up by 5 unit cells and matching sections. The high periodicity of the lattice combined with the high gradients in the small gap dipole magnets yield a small emittance of 1 nm.rad with good dynamic aperture and momentum acceptance [1]. In the matching section, soft end dipole magnet is introduced to reduce the synchrotron radiation power hitting the upstream straight section [2]. In this paper we present part of the cure to the resistive wall related instabilities by over compensation of the chromaticities. Also the closed orbit correction scheme used to compensate for the magnet elements errors is studied. MAX-IV LATTICE EVOLUTION The MAX-IV lattice is designed to take advantage of the features of small gap and short period superconducting undulators. This opens the possibility for using small magnet aperture with strong multipoles and hence keeping the ring circumference short with very small emittance. The original lattice [1] was with high bending field in the matching magnet which constitutes rather high heat load on the upstream superconducting insertion device. The matching section is modified by introducing a soft end bending magnet with 0.2 T [2] in order to minimize the synchrotron radiation power hitting the SC insertion devices. The principal parameters for the latest lattice are given i