The ALBA Synchrotron has developed a new girder system designed to meet the demanding mechanical stability requirements of ALBA II, the upcoming upgrade of the facility. These girders are key structures that support magnets, vacuum chambers, and diagnostic systems while ensuring their precise alignment along the accelerator.
In particle accelerators, girders are critical mechanical structures that must maintain the position of components with micrometre accuracy, while suppressing drifts and vibrations that could degrade beam quality. Even minimal vibrations or mechanical deviations can affect the trajectory and properties of the electron beam, having a large impact on the photon beam at the beamlines.
These girders must provide an excellent stability against external vibrations and good thermal stability, including high adjustment precision, with acceptable manufacturing costs.
While the current ALBA storage ring operates with 264 magnets distributed in 32 girders, the future machine will integrate 760 magnets in 80 girders within the same circumference, dramatically increasing the density of components, with distance between magnets as small as 10 mm. Such compactness introduces additional constraints like tighter spatial tolerances between components, and reduced margins for alignment errors.
To address these challenges, the new girder system must achieve positioning accuracies on the order of 50 micrometres between adjacent magnets, while maintaining long-term stability despite environmental and structural changes, such as slab deformation or temperature changes.
Read more on the ALBA website
Image: Girder Prototypes installed at the ALBA experimental hall with dummy magnets ready for testing
Credit: ALBA