STATUS OF THE EBS
resume operation at the nominal current of the 16-bunch and 4-bunch fillings (i.e., at 90 mA and 40 mA), respectively, within a year.
The first USM run ended on 14 October with a Mean Time Between Failures (MTBF) of 37.4 hours and 94.5% beam availability, related to teething problems that were progressively solved and to the necessary replacement of a defective vacuum chamber that had impacted beam availability. The second USM run that started on 27 October was only interrupted by eight trips, giving an MTBF of 75 hours and 98.7% beam availability.
BEAMLINE RESTART PROGRAMME
The beamline restart programme commenced officially on 2 March (Figure 3) and was interrupted by the nationwide lockdown on 16 March. After the restart of the accelerator complex, most of the remaining commissioning time until the next scheduled accelerator shutdown in June was used for the initial start- up of the beamlines and the required radiation safety tests for all operating beamlines. The bulk of the commissioning with beam was performed in July, followed by the summer shutdown in August. Most of the efforts were dedicated to the fine tuning and debugging of the new beamline control system, BLISS (page 177), on a large number of beamlines, as well as the restart of the old control system, SPEC, on the remaining beamlines.
On 25 August 2020, almost all ESRF public and CRG beamlines resumed operation in USM with the exception of those undergoing construction (EBSL3 BM18 and EBSL8 ID29) or major refurbishment/reconstruction (ID24, BM23, ID27, BM07 and BM14). Most beamlines
Fig. 3: Intensive beamline commissioning took place from March and throughout summer 2020.
observed an increase in brightness as expected, in particular on former low-β straight section and nano-focusing beamlines, in addition to significantly enhanced beam stability. Work continued to ensure transparent injections on the beamlines, given the frequent injections in top-up filling mode, and the new beamline control system, BLISS, underwent significant debugging and development work to improve its operation. To respond to the limited travel possibilities imposed by the COVID-19 pandemic, the ESRF implemented new guidelines for beam-time allocation for the 2020-II period, such that a majority of experiments could be conducted or followed up remotely, with mail-in and remote access successfully implemented on all beamlines at very short notice (pages 175 and 178). The user programme and further beamline commissioning efforts were carried out in parallel during the autumn.
PUBLIC BEAMLINE UPGRADE
Of the four selected EBSL beamline projects: EBSL1 ID18: Beamline for coherence applications EBSL2 ID03: Beamline for hard X-ray diffraction microscopy EBSL3 BM18: High-throughput large-field phase-contrast tomography beamline EBSL8 ID29: Serial crystallography beamline
EBSL3 and EBSL8 are in the implementation phase, while EBSL1 is in the Technical Design Report (TDR) phase and EBSL2 has delivered its TDR.
The construction of the experimental hutch for EBSL3 BM18 in the satellite building started after the longer-than-expected downtime due to the COVID-19-induced ESRF closure. The design of the scientific instrumentation for the beamline has been finished and its production is ongoing. Construction of the infrastructure (experimental and control hutches, HVAC) for EBSL8 ID29 will soon be finished and the procurement of the scientific instrumentation is advancing as planned.