Progress of prototypgpg in the SOLEIL storage ring upgrade project The upgrade of the SOLEIL storage ring is based on very ambitious in performance. A full characterization of the pumping properties target objectives in terms of equilibrium emittance (80 pm.rad with CO, H, O is now underway and shall back up these2 2 natural emittance while keeping the 2.75 GeV electron energy) results obtained with COgas. A Photo Stimulated Desorption2 and local beta functions at the Insertion Device (IDs) locations beamline (PSD, Figure 2) has been installed in the storage ring (1-1.5 m) for a 20-cell ring of only 354 m circumference. This tunnel in 2020 taking its beam from the exit beam of the dipole inevitably involves some technical challenges on the storage D08-1 it aims at qualifying these narrow chambers under real ring design which have to be addressed. In order to mitigate conditions by measuring the dynamic pressure as a function these challenges, an intense R&D program on simulations, of the photon dose. prototyping and beam measurements was started during the CDR phase of the project and will continue during the TDR FIGURE 1 phase. The prototyping program is primarily focused on the areas with the highest technical risk, such as Ti-Zr-V NEG (Non-Evaporable Getter) coating efficiency in very small vacuum chamber diameters (10 - 12 mm), extensive use of permanent magnets and high performance in-vacuum nonlinear injection kicker. The program has been extended to equipment such as the BPM blocks (10 mm diameter and 3 mm feedthrough) and bellows (60 mm length) for their unprecedented small dimensions and includes also innovative insertion devices. NEG COATING CHARACTERIZATION OF SMALL DIAMETER CHAMBERS The NEG coating is the most optimized solution in the case of the new generation storage rings where the size of the vacuum chamber becomes very small (10 to 20 mm diameter). The extensive use of this technology has been pioneered for the current storage ring (56% of the ring circumference) where the FIGURE 2 vacuum vessel dimensions for the quadrupoles and sextupoles are 70 mm x 25 mm. Figure 1 presents the pumping property measurements on a 38 mm, 20 mm and 10 mm inner diameter NEG-coated vacuum chamber for CO (in the framework of the2 collaboration agreement between SOLEIL and SAES-Getter Spa). The same activation procedure and test protocol have been followed on all the chambers (activation with a 24h plateau at 200°C; evolution of the upstream and downstream pressure ratio for a gas injection pressure of 10 mbar through a 1 l/s-7 conductance). With an activated NEG coating, using a test bunch laboratory, all the chambers show a similar behavior for the evolution of the pressure ratio with an increasing number of injected molecules: for CO the sorption capacity is over2 10 mbar.l/cm and the initial sticking probability over 0.1 which-6 2 demonstrate that the pumping properties of an NEG coating can be preserved even with 10 mm inner diameter chambers. In addition, a few reactivation cycles show no significant degradation 96