Nonlinear Optics Studies on the MAX IV Storage Rings

Abstract: The MAX IV Laboratory in Lund, Sweden, houses two electron storage rings operating at the energies 1.5, and 3 GeV. Both of these produce high-brilliance synchrotron radiation for beamline users. While the 1.5 GeV storage ring is a conventional third generation storage ring, employing a double-bend achromat structure, the MAX IV 3 GeV ring is the first realised fourth generation synchrotron. This ring employs a 7-bend achromat lattice structure to achieve a horizontal emittance of a few hundred pmrad. The multi-bend achromat design is the basis for many fourth generation synchrotron light sources. These lattice designs often require strong non-linear magnets in order to achieve their desired performance in terms of momentum acceptance and dynamic aperture, which in turn is needed to achieve the requirements in terms of beam lifetime and injection efficiency. The MAX IV 3 GeV storage ring itself is no exception, as it has a large number of chromatic sextupoles designed to minimize quadratic chromaticity. It also employs largely harmonic octupoles to minimise the amplitude-dependent tune shifts. Because of the high requirements of the fourth generation storage rings' non-linear magnets, it is of general interest to find schemes which allow for accurate tuning of these elements, as well as the characterisation of the non-linear optics of the accelerator. Schemes of these types are already well established when dealing with the linear optics of a storage ring, and need now be developed further for the non-linear case. This thesis presents schemes and results regarding the characterisation, correction, and optimisation of the non-linear optics of the MAX IV storage rings. These studies are mainly focussed on the MAX IV 3 GeV ring, but are aimed to be general enough that they can be applied on most fourth or third generation storage rings. This thesis also presents a specific case of the non-linear dynamics of a storage ring, where its properties are used to achieve pseudo single bunch through transverse resonance island buckets.