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European Cluster of Advanced Laser Light Sources

Periodic Reporting for period 2 - EUCALL (European Cluster of Advanced Laser Light Sources)

Reporting period: 2017-04-01 to 2018-09-30

The European Cluster of Advanced Laser Light sources (EUCALL) was a European Union-funded project which grouped most accelerator- and laser-driven X-ray research infrastructures (RIs) in Europe, operated for use by the wider scientific communities, so-called user facilities. Researchers from diverse science disciplines perform investigations using these facilities, leading to new scientific know-how, materials and, possibly, to new products. Europe has a leading position worldwide in Photon Science applications and technology, and the overall network of accelerator- and laser-driven user RIs is one fundament of this position. The overlap between optical lasers and accelerator-based X-ray light sources had been limited due to differences in their properties and their applications. Optical lasers are now so powerful that they can drive sources of X-rays and this community now builds and operates large RIs providing these secondary X-ray sources to users. At the same time, the development of accelerator-driven X-ray free-electron lasers now allow the generation of X-rays with laser properties, enabling to apply experimental techniques which until recently only where available for the (near-)visible spectrum using laser sources. Both of these developments started to fill a longstanding gap between the laser- and accelerator-based RIs.
Within EUCALL, accelerator- and laser-based RIs cooperated for the first time on common technical, scientific, and strategic issues, with the goal to make the future operation of these facilities more efficient, and therefore more sustainable. EUCALL developed solutions to technology and operation needs common to these RIs. Examples of technology developments within EUCALL include new standardized sample holders, new sensors and detectors for X-ray beams, new computer software to fully simulate experiments at the various light sources, and new schemes for ultrafast data transfer for experiments at the RIs. EUCALL developed methods and processes and enabled an exchange of know-how between the facilities, which together will enable the RIs, and also the wider light source communities, to better exploit the great research and innovation potential that these RIs provide. Through its results, EUCALL further harmonized the landscape of both classes of photon science RIs in Europe and beyond.
To better understand the full scope of existing methods and experimental opportunities, their comp¬lementarity, and to identify opportunities for future collaboration and developments, EUCALL collected and analyzed data about the current instrumentation at each RI, and incorporated the data into a publicly available database. A second data collection was made to study how the different RIs support various types of innovation. Three workshops were held to enhance experience exchange between the laser and accelerator communities, and further activities allowed EUCALL to suggest joint foresight topics for accelerator and laser RIs in Europe.
A new software package, SIMEX, was created to simulate various types of experiments using different X-ray light sources. The simulations track the X-rays on their way from the photon source to the sample and further to the X-ray detector and data. Scientists from EUCALL’s facilities integrated individual programs that simulate different steps of the experiment chain and connected them with new interface software to build a platform that researchers can use. SIMEX is publicly available for anyone to access.
Modern X-ray experiments generate large amounts of data on ultrashort timescales. Most computing systems cannot keep up with the high data rates and new solutions are needed. EUCALL’s scientists identified what their various scientific applications have in common, in terms of data rates and formats. This led to definition of best practices for high data rate analysis. EUCALL applied these practices to develop a library of efficient algorithms for data acquisition and online processing at its RIs.
Each X-ray source has its own kind of sample holder for different experiments. EUCALL designed a standardized sample holder for experiments requiring fast and precise sample exchange. This allows users of different photon science RIs to freely exchange samples. Users can prepare their samples on this sample holder and ship them to any of EUCALL’s facilities. EUCALL’s system has an “intelligent” sample scanner which uses a microscope to automatically detect where the interesting regions are. EUCALL’s system then positions the sample into the X-ray beam for the experiment. Prototypes of hardware and software to run this new system were built and tested, and have been installed at several RIs.
Each of EUCALL’s RIs generates intense, ultrashort and partially coherent X-ray pulses with properties often changing from pulse to pulse. For scientific applications it is paramount to measure these properties without altering the pulses significantly. In EUCALL the performance of various specific developments was investigated and the techniques were applied at other EUCALL RIs. Four methods were developed: a residual gas-based X-ray intensity monitor, two different techniques to measure the time delay between laser and x-ray pulses, and a wavefront sensor, which measures the “shape” of an X-ray pulse. Prototypes of each of these new systems were tested by EUCALL’s scientists.
Dissemination of EUCALL’s results was achieved using project dissemination material, press releases, social media, publications, and at scientific conferences and other events.
EUCALL developed technology and contributed to process optimization reaching beyond the present state of the art in instrumentation, science outreach and operation of RIs, being themselves at the edge of present-day technologies. For sample holder devices new processes and standardization schemes will enable investigations requiring high repetition-rates and high-precision positioning devices. In the area of new x-ray diagnostic tools, EUCALL tested and implemented new methods and devices, and enabled the use of these devices to spread to all RIs. EUCALL’s solutions for the simulation of experiments are already enabling users to perform experiments more efficiently and, therefore, more successfully. New schemes for ultrafast data services will enable on-line data inspection, make experiments more efficient, and support data analysis. These technology and process advances will benefit RIs and researchers. Furthermore, EUCALL results allowed exploitation and development of synergies amongst the EUCALL RIs, e.g. in the analysis and development of the instrumentation portfolio, in operational procedures, and also in providing know-how and experience exchange for activities supporting innovation. EUCALL provided important know-how for the start of operation of two international ESFRI facilities, the Extreme Light Infrastructure and European XFEL. Exploiting the combined expertise of the laser and x-ray communities, EUCALL was a bridge between the accelerator- and laser-driven light source RIs, benefitting the larger European Research Area and the various communities of researchers using these RIs. EUCALL’s cooperation was unprecedented worldwide and significantly contributed to Europe’s competitiveness and leadership in terms of research and innovation capacity.