SwissFEL is a hard X-ray FEL facility at the Paul Scherrer Institute in Villigen, Switzerland. This user facility produces X-ray pulses at greater than 12 keV in energy with durations as short as 20 fs. These provide critical insight to researchers in a multitude of fields including atomic and molecular physics, materials science and technology applications.

ASTeC was involved in the development of SwissFEL from 2011 and carried out a number of work packages that influenced the final design of the machine, including the design and construction of the laser heater undulator. This is a vital part of the accelerator used to overcome microbunching instabilities in the injector and improve the quality of the electron beam. SwissFEL also made late changes to the previous design of the Athos FEL to implement High-Brightness SASE, a novel FEL scheme proposed by the MARS group at ASTeC that will greatly improve the quality of the FEL output compared to the nominal Self-Amplified Spontaneous Emission (SASE) mode of operation.

ASTeC staff members helped out with the first commissioning of SwissFEL and were present during first beam transmission through the machine. Soon after that the SwissFEL team achieved 'first lasing'. ASTeC continues to collaborate with SwissFEL scientists on an ongoing basis by visiting the facility to participate in machine operations and by working together on novel concepts that may continue to improve particle accelerator and FEL output in the years to come.  ​