SOLEIL II is an upgrade project of the existing Synchrotron SOLEIL facility. It aims to reach fourth-generation light source parameters. This includes reductions of the transverse beam emittance, vacuum chamber dimensions and momentum compaction factor. A new impedance model of the SOLEIL II storage ring was developed. This paper demonstrates the evaluation of transverse single- and coupled-bunch instabilities with an up-to-date impedance model. Storage ring operation with a harmonic cavity is an essential component of the project. A harmonic cavity provides bunch lengthening and perturbs synchrotron motion. Its effects on transverse instabilities in SOLEIL II are reported in this contribution.

The Innovation Fostering in Accelerator Science and Technology (I.FAST) project aims to enhance innovation in the particle accelerator community, mapping out and facilitating the development of breakthrough technologies common to multiple accelerator platforms. Task 7.2 of the I.FAST project, Enabling Technologies for Ultra Low Emittance Rings, focuses on networking in the area of low emittance rings dominated by the recent X-ray storage ring upgrades and exploiting synergies with existing and future e+/e- colliders. Strengthening networking activities in essential technologies ranging from magnet design, RF systems, vacuum, injection systems to feedback systems and beam instrumentation leads to a state where technological difficulties are shared, so that the R&D path is strongly linked to other facilities and scientific fields. Such a state also stimulates joint organizations to collaborate on projects with organic links worldwide. To facilitate networking, Task 7.2 has so far organized several thematic workshops, and is planning further workshops to prepare opportunities to strengthen networking. In this contribution we present our activities in the past and for the future.

Previous TDR (Technical Design Report) studies for the SOLEIL upgrade project (SOLEIL II) have converged towards a lattice alternating 7BA and 4BA HOA (High Order Achromat) type cells providing an ultra low natural horizontal emittance value in the 85 pm·rad range at an energy of 2.75 GeV. The new TDR lattice is an evolution that keep the insertion devices photon source points at their present location, allows a better relative magnet positioning and more space for accommodating photon absorbers, BPMs (Beam Position Monitor) and other mandatory diagnostics. This last evolution includes a better modeling of all the bend magnets based on their realistic field profiles and the accommodation of height super-bends for beam-lines as well as for beam size diagnostics. In addition an exhaustive investigation of the systematic and especially the cross-talk multipoles as well as the phase 1 portfolio of insertion devices impacts has been carried out. This paper reports the linear and the non-linear beam dynamic optimizations as well as future directions for performance improvement.

The synchrotron SOLEIL is the French third-generation 2.75 GeV synchrotron light source, a research laboratory at the forefront of experimental techniques for the analysis of matter down to the atomic level, and a service platform open to all scientific and industrial communities. We present the performance of the accelerators, which deliver extremely stable photon beams to 29 beamlines. We report on last year's overall performance figures and the operation of the brand-new cooling station. As the optimization of the energy and carbon footprint becomes more and more prevalent in France and Europe, actions for a more sustainable operation are given. Several incidents are also presented, together with the lessons learned to avoid recurrence. Major research and development activities related to component obsolescence and the SOLEIL II project will also be presented.