5 2 H I G H L I G H T S 2 0 2 2 I
S C I E N T I F I C H I G H L I G H T S
C O M P L E X S Y S T E M S A N D B I O M E D I C A L S C I E N C E S
The year 2022 was a fruitful year for the Complex Systems & Biomedical Sciences group beamlines with users onsite, many excellent experiments and scientific exchange with visiting scientists. This second year of operation with the Extremely Brilliant Source (EBS) was marked by a gradual increase in the number of publications based on data obtained with the new source. Some examples of these works are mentioned in this chapter.
At ID02, the time-resolved ultrasmall-angle X-ray scattering (TRUSAXS) beamline, the past year has been primarily a period of hectic user operation. As mentioned above, publications from the experiments performed using the EBS have begun to appear in print. Notable examples include the high-resolution structural elucidation of extremely swollen microemulsion phases using Rheo-SAXS  and probing the emergent dynamics of light-induced active colloids by means of X-ray photon correlation spectroscopy (XPCS) . Another interesting work is the identification of the mechanism of the early stage of tubulin nucleation using time-resolved SAXS combined with stopped-flow temperature-jump . The EBS is helping to advance structure-function studies of cardiac muscle activation from the cellular level down to the filamental regulatory proteins. This list is not exhaustive, and we look forward to some of these works appearing in the next edition.
ID09 is the beamline for time-resolved experiments with time resolution down to 100 ps. Thanks to the re-coated ceramic injection kicker chambers that were reinstalled in March 2022, the accelerator has been able to deliver 7/8+1 and 4-bunch modes at nominal single-bunch current (8 mA and 10 mA, respectively), which has allowed experiments to be performed with a factor two increase in intensity with respect to 2021, thus fully exploiting the new capabilities of the EBS. A new diagnostic chamber has been installed close to the sample position to monitor the intensity, pulse duration and position of the X-ray beam. A live feedback system makes it possible to automatically compensate for any drift in the vertical beam position by fine adjustment of the toroidal focusing mirror inclination through a piezo actuator. BLISS, the new beamline control system developed at the ESRF, is now fully operational at ID09 and is routinely used to perform time-resolved experiments with different X-ray pulse durations and/or data collection repetition rates. Among the experiments performed in 2022, probing light-induced phase transitions has been particularly successful, as these experiments greatly benefit from the improved spectral purity and smaller size of the EBS beam.