The ASD is progressing with the technical design study (TDS) for the Accelerator Phase II Upgrade, which is focused on greatly improving the brightness of the source by decreasing the horizontal equilibrium emittance of the storage ring from the current 4 nm to 150 pm. This will be possible by replacing the present 32-double bend achromat arcs with a much more compact lattice based on a hybrid 7-bend achromat (see Figure 160). The smaller emittance, together with shorter-period, smaller-gap undulators and new beamline optics optimised to take full advantage of the new source, will allow a general improvement in performance by about a factor of 100.

The S28 design for the ESRF’s new hybrid 7-bend achromat lattice

Fig. 160: The S28 design for the ESRF’s new hybrid 7-bend achromat lattice.

There are several design restrictions, including maintaining the present injection complex and injection scheme, as well as the existing straight sections and beamlines, in an almost unchanged state. The existing arc hardware, such as some power supplies, vacuum system components and diagnostics must also be reused as much as possible. Another design goal is to reduce operation costs, specifically wall-plug power.

On 5th and 6th September 2013, the newly formed Accelerator Project Advisory Committee (APAC), nominated by the ESRF Council, reviewed the project and current progress in the development of the TDS. A status report of all the main activities, grouped in working packages (Beam Dynamics, Magnets, Electron and Photon Beam Transport, Power Supplies, Radiofrequency, Implementation, Diagnostics and Beam Control, Photon Source and User Interface, Injector Upgrade), was presented to the Committee. The APAC report was very positive and the Committee strongly supports the effort of the ASD towards the completion of the TDS. Three more meetings are planned before the end of 2014, with a detailed report given from the APAC to the Management and the Council each time. The project team is now preparing the TDS report to be presented to the committees in spring 2014.