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A C C E L E R A T O R A N D S O U R C E

The Accelerator and Source Division (ASD) is in charge of the production of synchrotron light from the Extremely Brilliant Source (EBS), the Phase- II Upgrade of ESRF s 6 GeV storage ring. Launched on 25 August 2020, the EBS has been operating in User Service Mode (USM) for more than three years. Thanks to the efforts of all the staff in the ASD, Instrumentation Services and Development Division (ISDD) and Technical Infrastructure Division (TID), and due to the continuous preventive maintenance of all the hardware systems and updates of equipment, good machine performance was maintained in 2023. The yearly figures were, however, affected by a broken cooling-water tube in the injection septum magnet in November, which directly led to a beam availability of 97.85% for the year 2023 (from 17/01 to 13/12). The Mean Time Between Failures (MTBF) reached 105.6 hours, which is 17 hours longer than 2022. The Mean Duration per Failure (MDF) increased to 2.3 hours due to the long intervention needed to repair the septum. A total of 5492 hours of beam time was officially scheduled for delivery to users in 2023, which remains the normal level of beam delivery time as before the pandemic. 2023 is the second year of EBS with a full USM operation schedule. In addition to the EBS operation, much of the Division s development work in 2023 focused on the consolidation and sustainability of EBS operation and the improvements of its beam performance.

Due to the lack of spare parts for the current kickers in the EBS storage ring, the nominal beam current in 16-bunch mode was not reached. The procurement of the newly designed kicker and shaker ceramic chambers is ongoing after they were contracted to the company SOLCERA for manufacture. The nominal 16-bunch mode beam current is expected to be reached in late 2024, after the delivery of all four kickers.

The Hotswap system, which covers all the power supplies to the quadrupoles around the storage ring, was deemed ready for deployment in full operation by the end of 2022, after the tests carried out during Machine-Dedicated Time (MDT). The development of the TANGO controls and user interface for the Hotswap system were also completed in 2022, resulting in improved robustness of the system. At the beginning of 2023, the Hotswap system entered full-time operation. In the whole year of USM operation, only one event of automatic swap of a corrector power supply occurred, when the power supply failed during USM operation, which shows the excellent performance of the Hotswap system.

The Solid-State Amplifier (SSA) project to replace the klystrons operating with the radiofrequency (RF) cavities in the EBS storage ring is in the procurement phase. A fourth harmonic RF system is still in the design stage, although some of the technical challenges were overcome in 2023. This will be helpful to increase the Touschek beam lifetime in the operation of the timing modes with nominal beam currents, and in the meantime, to reduce the parasitic heating on the accelerator vacuum elements.