HIGH PERFORMANCE IN-VACUUM NONLINEAR RF-BELLOWS INJECTION KICKER In order to be able to minimize beam induced heating, the effect The other key technology to ensure the feasibility of the lattice of collective effects and to store a total current of 500 mA as and in particular an efficient injection of the electrons, is the need today, the vacuum chamber connections (flanges, bellows) to develop a new high performance nonlinear multipole injection where RF continuity is required need a very special attention. kicker (MIK). This should allow the electrons to be injected at We have initiated two prototyping programs based on an a very short horizontal distance (3.5 mm) from the storage ring adaptation to the SOLEIL upgrade needs of successful designs beam axis, in top-up transparent mode, without compromising already used on different accelerators projects. Figure 5 shows on the aperture of the vacuum chamber. An in-air MIK magnet the early mechanical designs for the RF-shielded bellows of the prototype has already been made and has been magnetically SOLEIL upgrade. Mechanical feasibility, vacuum performance, measured in-house with excellent results, as a step towards thermal cycling and electrical contacts will be soon investigated proving the feasibility of these new MIK. Some difficulties still in relation to the total ring impedance budget. need to be overcome in the design of a complete in-vacuum MIK FIGURE 5 magnet, such as final titanium coating, mechanical integration, with great care on the conductor position tolerance or the voltage withstand of such new compact magnets. Special care will be taken in the design of all elements to facilitate manufacturing and maintenance. These difficulties should be resolved during the TDR phase with the early design of the final in-vacuum magnet starting in 2021. The patent filing process for these news MIK topologies is underway. OTHER PROTOTYPES BEAM POSITION MONITORS The Beam Position Monitors (BPM) sensors for the SOLEIL INNOVATIVE INSERTION DEVICES upgrade will be the usual RF button pickups installed at 45° For the intermediate photon energy range (10 eV – 5 keV) with on the vacuum chamber. While the technology is well known, adjustable polarization, contrary to the approach of present it will be the first time the pickups are mounted on such a small SOLEIL where two Elliptical Polarized Undulators (EPUs) are vacuum chamber aperture (10 mm diameter). The challenge installed one after the other in the medium straight section, only will be the manufacturing of a small dimension pickup (with a one Insertion Device (ID) will cover the whole spectral range in the 3 mm diameter button) and its positioning on the BPM body upgraded ring. This presents a real challenge, since a trade-off with respect to tight tolerances in order to maintain an absolute must be made between the best possible performances over a position measurement error below 300 µm. A first (simplified wide spectrum and the minimization of the total power emitted version) prototype (Figure 4) has been realized in order to validate by the ID and its effects on the machine design and electron such a tight mechanical integration and also to try new ideas beam dynamics. Three technical options are being explored for the button positioning during the welding process. The to cover the intermediate photon energy range with adjustable metrological results are promising and improvements on the polarization: dual EPU, bi-periodic undulator, cryogenic APPLE III dedicated mechanical tools are already planned. The targeted undulator (CPMUE). The bi-periodic undulator is a new type resolution of the BPM is 50 nm RMS in closed orbit measurement. of ID capable of switching the magnetic period value from its FIGURE 4 original value λ to 3 λ. The studies u u started in the CDR are ongoing and a prototype will be launched as part of the TDR. Although it gives the best performance in terms of flux and brilliance, the in-vacuum cryogenic APPLE-III undulator is a very challenging ID. 98