CERN Accelerating science

EuPRAXIA baseline parameters established
by Dr. Ricardo Torres (University of Liverpool)

Photograph of the participants at the 1st Yearly Meeting of EuPRAXIA
(Image:Copyright Pieyre Sylvaine, LLR)

The First Yearly Meeting of the EuPRAXIA consortium took place at the École Polytechnique in Paris, over 26-28th October. Ralph Assmann, Project Coordinator, and Arnd Specka, Deputy Project Coordinator and Host of the meeting, welcomed 59 registered participants from partner institutes, associate partners, and industry.

The Yearly Meeting discussed the fruitful first year of the project, which included the forming of the collaboration board, hiring of new personnel, investigation of facility parameters and a total of eleven workshops and special work package meetings. Scientific results from these events covering all aspects of the project were reported, and included interesting new insights and future directions.

One of the highlights of the meeting was the presentation and approval of the preliminary study concept of EuPRAXIA. The report summarized the scientific input for the preliminary study concept of EuPRAXIA which has been received over the past year. All work packages contributed to this report with summary reports of topical workshops held during 2016.

One such workshop was the European Plasma Accelerator meeting held in Pisa in June 2016, where more than 120 scientists gathered and discussed the various technical approaches and requirements for the collaboration over three days. Another workshop on laser technology which lead to the 100-cube laser challenge (100J / 100fs / 100Hz) has become one of the baseline components of the EuPRAXIA design.

The preliminary study concept report presents the outcome of all these discussions, condensed into flow diagrams and technical tables. The graphical diagrams show the main concepts, their interplay and the connections to relevant applications. Included in the report are the agreed baseline parameters, the parameter ranges to be explored and the technical goals for the next step of the EuPRAXIA conceptual design work.

The values of the parameters were first derived from scaling laws and refined by simulations. The parameter ranges documented in the report will ensure that work done in different locations by the project partners will be focused on the same targets and operating under the same assumptions. This common baseline for parameters and their study range will also ensure that results can be compared for beam quality, tolerances, layout footprints and costs.

At this stage, the study will contemplate multiple paths for obtaining high-quality multi-GeV electron beams. Such concepts considered include: Laser Wakefield Acceleration (LWFA) with internal or external injection and direct or staged acceleration to 5 GeV; beam-driven Plasma Wakefield Acceleration (PWFA) to 1 GeV or 5 GeV; and a hybrid scheme including LWFA and staging using PWFA to a multi-GeV electron beam.

By keeping these common baseline parameters and goals in mind, the work packages of EuPRAXIA can further investigate the techniques and approaches required.

In addition, the report contained the requirements for the plasma-based accelerator and its experimental user areas tailored for the two main applications foreseen by EuPRAXIA. Firstly, High Energy Physics and other pilot applications, and secondly, a Free Electron Laser (FEL) for ultrafast photon science.

The values for the FEL requirements were determined during several workshops held over the last six months. The requirements for the HEP applications in terms of beam parameters and infrastructure were defined by the participants of a workshop on Pilot Applications of Electron Plasma Accelerators (PAEPA) in mid-October 2016.

In the next phase of the project, the technical work will use the parameters from the preliminary study to provide a more refined table of parameters for incoming and outgoing beam and laser properties, realistic estimates of performance, basic values for tolerances and stability requirements, basic layouts (footprints) of the technical components, and a further iteration of specifications for the science applications.

The future outcome from the work packages could be used to rank the various solutions towards the final proposal, due in 2019. This ranking will define the optimal combination of technologies for the conceptual design of a EuPRAXIA facility.

by Prof. Carsten Welsch (University of Liverpool)

EuPRAXIA and EuroNNAc members gather for the meeting in Pisa, Italy (Image courtesy of EuPRAXIA)

Particle accelerator experts from around the world joined experts from the laser and novel accelerator communities to discuss the design of an innovative European plasma accelerator within the framework of the EuPRAXIA and EuroNNAc projects.

The workshop took place between June 29th and July 1st at the Area della Ricerca in Pisa, Italy and was hosted by the Istituto Nazionale di Ottica – CNR.

The local organiser, Leo Gizzi said: “It has been an absolute pleasure to see the vibrant discussions amongst participants. The definition of the key parameters of such an international facility with global reach and impact is one of the most exciting things a researcher can be part of. The event gave us the opportunity to reflect on the state-of-the-art and at the same time outline the R&D programme required to reach our goals by the end of the design study.”

The design and science cases of advanced plasma accelerators are subject of intense studies around the world. Progress in proof-of-principle experiments has led to the expectation that ground-breaking applications of plasma accelerators will become available in the next few years.  

Ralph Assmann gives a speech to attendees at Pisa meeting
(Image courtesy of EuPRAXIA)

More than 120 delegates discussed the parameters and technical specifications required at the interfaces between lasers and plasmas, plasmas and particle beams, as well as particle beams and other applications such as Free Electron Lasers, High Energy Physics detectors and ultra-compact X ray devices. Discussions also covered the specific requirements in beam diagnostics, laser technology and underpinning simulation codes.

The aim of the meeting was to collect the input from all interested parties in order to define a full parameter set that will be used as the core of a conceptual design for a European plasma accelerator with industry beam quality that shall now be developed by the project partners until the end of 2019. Targeted workshops will now be organised by each of the EuPRAXIA work packages in order to build up on the Pisa discussions and further refine all parameters.

All presentations and further information can be found on the workshop’s indico page. For more information about EuPRAXIA, please refer to the project website.

by Alexandra Welsch (University of Liverpool)

The Horizon 2020 Design Study EuPRAXIA targets the preparation of a conceptual design report for the world’s first plasma-based accelerator at 5 GeV with industrial beam quality and two user areas. The laser systems to be used as drivers for the laser-driven plasma acceleration process and as part of the laser injector are crucial for the success of the project. Their development and optimization are addressed within Work Package 4 of this pan-European project. On 18 May 2016 experts from within this Work Package held a first Topical Workshop on the laser system at the synchrotron SOLEIL in France. 

At the beginning of the event highlights from current and future laser development projects, including the Extreme Light Infrastucture (ELI) project, the APOLLON, and the ILIL PW facilities were presented. These lasers shall cover energies ranging from ten Joule up to kilo-Joule, pulse durations from attoseconds to hundred femtoseconds, and repetition rates from one shot per minute to 10 Hz. It was emphasized that these projects needed tremendous investments and major developments in new materials arising from research projects launched as early as 2006.

A wide range of laser technologies and quite different architectures emerged from this overview, suggesting a range of potential solutions for the development of the future EuPRAXIA laser concept. A “100 cube” operating point was considered, providing 100 Joule, 100 fs pulses at 100 Hz, with a contrast of 1010 at 10 ps. Whilst ambitious for a scientific laser issued in 2025, it was found a generally realistic scenario, with warnings about a potentially longer timescale needed to attain an "industrial" version of such a system.  The key parameters and overall design will now be further investigated within the Design Study.

These ongoing developments will now be put into a bigger context. EuPRAXIA is organizing a Workshop on a European Plasma Accelerator in Pisa, Italy between 29 June to 1 July 2016 at Area della Ricerca del CNR, Pisa, Italy hosted by Istituto Nazionale di Ottica - CNR. This event will be open to the communities of conventional facilities, lasers and novel accelerators, to discuss the unique scientific and industry opportunities arising from the EuPRAXIA design.