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with the mechanical design of the injection section for transparent injection, is still ongoing. Efforts to lower the natural horizontal emittance, together with the off-energy lattice of the storage ring, have been successful, with an operational beam lifetime and good injection efficiency after optimisation of the beam optics and closed orbit distortion corrections.
The test of the mini-β scheme, following the installation of additional quadrupole magnets on ID31 during the winter shutdown of 2022, is foreseen to be carried out in spring 2023 before the summer shutdown, after all the preparative work in the EBS storage ring tunnel is finished. The mini-β scheme will be conducive for the enhancement of the brightness and coherence of the produced X-rays in the near future.
New insertion devices (IDs) are continuously in procurement, and the assembly, installation and commissioning are in line with the construction of the beamlines and medium- term scientific programme. The RF fingers of the cryogenic permanent magnet undulators (CPMUs) on ID15 and ID16, which were designed to allow LN2 circulation through the girders, experienced a heating problem when the bunch current was increased in the 16-bunch timing mode, limiting the beam current in USM operation to 65 mA. Newly designed RF fingers, with better contact with the connections of the CPMU, were successfully installed on the CPMUs of ID15 and ID16, and the new CPMU18 on ID27. With these new contacts, the beam current in 16-bunch mode was upgraded to 75 mA during USM operation from August 2022. Besides the newly installed IDs, the CPMU16.4 for ID29 was assembled for its magnetic blocks and was fully finished at the end of 2022. The magnet assembly of another CPMU16.4 for ID03 is also in progress. In 2022, the synchronisation between ID and monochromator, which is considered as the main ID control upgrade, was planned and the implementation started. This will improve the performance of IDs, and the reliability and maintainability as well. The project of synchronisation has also been identified as a major project by the ESRF management.
The stability of the electron beam and X-rays remains a key issue when the accelerator complex delivers beam to the users, and needs to be studied continuously. With the two X-ray beam position monitors (X-BPMs) installed in the beamlines of BM08 and BM16 in 2021, the stability is being studied, while the second version of X-BPMs are in preparation. The non-destructive vertical Halo-Monitors were set up and work as an excellent watch-dog to monitor vacuum incidents. The new phase monitor is highly appreciated for yielding precise results on slow and fast phases of the storage ring and the booster.
The ASD has also been involved in the Eurizon international collaboration project in 2022. A new transverse gradient dipole was designed in the magnet cooperation between the projects of PETRA-IV and EBS.
In conclusion, the EBS operation reached its objectives with better statistics than 2021 thanks to the great efforts and dedication of ASD staff and the valuable support given by the ISDD, TID and the Experiments Division. I would like to take this opportunity to thank all ESRF staff for their continued efforts in the operation of EBS and the accelerator development projects in 2022. Q. QIN