The experimental techniques used at the CoSAXS beamline will use a huge vacuum vessel with possibilities to accommodate two in-vacuum detectors in the SAXS/WAXS geometry. A major milestone was reached for the CoSAXS project when this vessel was recently delivered, installed and tested.
Ann Terry, researcher at CoSAXS, about the new vacuum vessel and the coming science at the beamline
See a few clips from when the vacuum vessel was delivered and installed
The main method that will be used at the CoSAXS beamline is called Small Angle X-ray Scattering (SAXS). By detecting the scattered rays coming from the sample at shallow angles, less than 4° typically, it is possible to learn about the size, shape, and orientation of the small building blocks that make up different samples and how this structure gives these materials their properties. The materials to be studied can come from various sources and in diverse states, for example, plastics from packaging, food and how it is processed or proteins in solution which can be used as drugs.
The “co” in CoSAXS stands for coherence, a quality of the synchrotron light optimized at the MAX IV machine, that loosely could be translated as laser-likeness. In the specific case of X-ray Photon Correlation Spectroscopy (XPCS), it lets the researchers not only measure the structure of the building blocks in the sample but also their dynamics – how they change in time.
To profit from the weak scattering signals from the materials under study, the X-ray detectors have to be placed in a vacuum. Also, the detector distance from the sample needs to be varied over a considerable distance, sometimes during one experiment and according to the needs of the experiment. The 17 m long vacuum vessel on CoSAXS will allow the characterization of sizes from approximately 1 Ångström to 1millimeter.
The full installation of the vacuum vessel took three weeks of work, including unloading, installation and extensive tests and the vacuum vessel. It is now in place and pumped down to its operating vacuum of about 10-2 millibar (air pressure is 1 bar). This major milestone for the project has been achieved thanks to a joint effort of the manufacturer AVS Added Value Solutions, the support groups of the MAX IV laboratory and the CoSAXS team.
The next phases for the beamline include the installation of the detectors, final components, and sample environment to hold the samples and the start of the commissioning of the X-ray optics with synchrotron light.
Further information about CoSAXS can be found at
AIP Conference Proceedings 2054, 030013 (2019)