Successful Science@FELs Conference held in Stockholm

Successful Science@FELs Conference held in Stockholm

Science@FELs 2018 in Stockholm


For the fourth time the Science@FELs conference was organized, this time in Stockholm in the AlbaNova University Center at Stockholm University between 24 and 27 of June. The preceding events took place in Hamburg, at PSI and in Trieste.

Science@FELs 2018 is a conference by FELs of Europe and focuses on the scientific highlights achieved during the last years at FELs and laser facilities world-wide. The conference in 2018 was co-organized by the Stockholm-Uppsala FEL center, the MAX IV Laboratory, the Lund Laser Centre, Stockholm University and Lund University.

Despite the long light Nordic nights of Stockholm combined with south European temperatures and a distracting football championship, around 160 participants joined the conference. They came to listen to talks on New developments, Imaging, Scattering, Condensed Matter Physics, Chemistry, Atomic and Molecular Physics, Bioscience and Matter under extreme conditions. In addition there were over 70 posters and a “Hot-topic session” with oral presentations on highlights from the posters. The speakers spanned the world from Stockholm, via Århus, Kiel and XFEL, FERMI, SOLEIL to LCLS and Spring-8. With Laserlab Europe being a co-organizer, one talk per session was chosen from a laser perspective, highlighting the integration in science between FEL and laser sources.

The conference started with four tutorials catching the spirit of lasers, X-ray FELs and light. Michele Svandrlik, head of FELs of Europe, and Claes-Göran Wahlström, head of Laserlab Europe, welcomed the audience and stressed the fruitful collaboration between lasers and FEL.

The FELs of Europe prize in recognition of recent work for scientific excellence in the area of FEL science and applications was, as reported separately, awarded to Dr. Jonas Sellberg from the Royal Institute of Technology (KTH) in Stockholm for “his innovative contributions by means of free electron lasers to the understanding of supercooled water”.

Ten students were supported to travel to the event in Stockholm by EUCall.

Taking advantage of the Swedish summer a Barbecue evening with Boule games, food and drinks emphasized the informal character and joyful approach to science, research and networking.

Michele Svandrlik and Wilfred Würth welcomed everybody to Science@FELs 2020 at DESY in Hamburg in September 2020, this time with a new XFEL in operation!

The event was supported by The Swedish Research Council, Structural Dynamics AIP and the Swedish Research Council.

Per Johnsson, Mats Larsson, Anders Nilsson and Sverker Werin


Forum on Advanced FEL Techniques in Stockholm 2018, 27-28 June


The Forum, being a Satellite event to the Science@FEL conference, gathered around 40 participants in a sunny and warm Stockholm with a distracting football event ever present.

Within Science@FEL the Forum is a key action in the exploration of FEL techniques and FEL user possibilities, especially joining the forces for an even more focused future development.

The Forum focused on bringing together FEL developers and Users, aiming at improving exchanges between the two communities. Plenty of time was therefore used for discussions that were introduced by review and highlight talks where users and FEL developers presented side-by-side, dedicated to important aspects such as coherence, photon pulse manipulation, high pulse energy, polarization control, ultrashort pulses, and production of multiple colour pulses.

Discussions soon deepened in how to match the broad-range of community-dependent requirements to different techniques available by FEL developments both in the soft and hard X-ray regimes.

Users pointed to the key characteristics of FEL pulses needed to fulfill experimental expectations. A large ensemble of users deal with time-resolved pump-probe experiments and are interested in relatively short pulses (down to a couple of femtoseconds) with well-synchronized and carrier-envelope stable pump-probe pulses over a large frequency range, from THz to optical and beyond. Timing, as an alternative to synchronization, is an option for some, while others see it as a workaround, difficult to conjugate to a large frequency-range of pumps, due to the need of dedicated timing tools at different frequencies.

Going towards single-particle imaging requires few-femtosecond pulses as well, but needs a large number of photons (Terawatt range) and shorter wavelengths allowing for sub-nm resolution. Studying ultra-fast phenomena goes even further, to sub-femtosecond single- or multi-pulse.

Applications dealing with warm and hot dense matter need mJ-level pulses with micrometer-size focus, while beams with stable and good degree of polarization are required for imaging magnetic domains. Finally, multiple-colour, high-repetition X-ray pulses are needed for site-selective, coincidence pump-probe experiments.

Another developing field discussed was OAM (Optical Angular Momentum) beams that can be created in FELs with helical undulators and how and if they can be explored. Moving particles by light was shown (not only inspired by Scottish folk music as presented by Brian McNeil).

Users were asked to dream, what is the “dream beam”? Perhaps it cannot be created, not in a single machine, but sometimes the FEL developers come up with new surprising schemes as the FEL is among the most versatile light sources out there.

It was proposed to continue and deepen communication between users and developers both by an electronic platform, where requirements can meet FEL development ideas, and future Fora.

The Forum was generously hosted by Stockholm University.

Gianluca Geloni (European XFEL), Luca Giannessi (Fermi) and Sverker Werin (MAX IV)