Sharper, smaller, brighter: Improved Focusing at PX III after the SLS 2.0 Upgrade

The New X06DA-PXIII Beamline 

The X06DA-PXIII beamline is a crystallography beamline on a superbend magnet at the Swiss Light Source. Since 2008, it has served the scientific community, contributing to 2650 Protein Data Bank structures as of today (i.e. before the SLS shutdown started in autumn 2023). Just before the upgrade of the storage ring, the beamline has been rebuilt with new X-ray optics to exploit the full potential of SLS 2.0. Its new design aims for a unique position in macromolecular crystallography beamlines worldwide: it exploits the excellent electron beam properties of the upgraded SLS and an advanced optical layout to focus the X-ray beam as sharply as possible onto the crystallography samples. 

Measureable Performance Increase after the SLS Upgrade

The SLS upgrade aimed to reduce the electron beam emittance and improve beam stability, providing smaller and more coherent X-ray beams across the facility. While bend magnet beamlines do not make full use of the ultimate brilliance of the new storage ring, they provide a good test case for how broadly these improvements carry through.

First results from commissioning the beamline before and after the storage ring upgrade show these clear, consistent gains in optical performance at the PXIII beamline. The X-ray beam is more stable over time, and the focusing capabilities increased significantly. A recent publication in the Journal of Synchrotron Radiation reports the first experimental results from the beamline (see figure below), showing that the X-ray beam that was spread out over more than 100 µm before the upgrade is now contained within a focus in the order of 20 µm. These effects are directly usable in crystallographic experiments, bringing the average time for obtaining a complete crystallographic set of data down to less than thirty seconds.