CERN Accelerating science

  Compact modern accelerators for big science
  By Carsten Welsch(UNILIV)

On 1 November 2015 a new European Design Study called EuPRAXIA (“European Plasma Research Accelerator with eXcellence In Applications”) started. 3 M€ of funding has been awarded to 16 laboratories and universities from 5 EU member states within the European Union’s Horizon 2020 programme. They will be joined by 18 associated partners that make additional in-kind contributions.

The goal of this ambitious project is to design accelerator technology, laser systems and feedbacks for improving the quality of plasma-accelerated electron beams. Two user areas will be developed for a novel free-electron laser, for high-energy physics and for other applications. An implementation model will also be proposed, including a comparative study of possible sites in Europe, a cost estimate and a model for distributed construction but installation at one central site.

Novel and small plasma accelerator compared to the FLASH accelerator. Credit: Heiner Müller-Elsner/Desy

EuPRAXIA has a total of 14 work packages that address specific scientific challenges. R&D in eight of them will be directly supported by the design study. This includes extensive simulation studies across the consortium to optimize the plasma, laser and electron beam parameters for both, the plasma injector and the accelerating modules. These investigations will target the achievable beam characteristics, including maximum energy and bunch charge, but also energy spread and transverse emittance of the electron bunches. It is hoped that they will also provide valuable information about acceptable tolerance levels with regards to error sources such as laser intensity and plasma density. Another work package aims at identifying a reliable and stable solution to build the injector and plasma accelerator stages. It will design the plasma structures that are required for both tasks and define optimum regimes of operation. Studies will also include the design of suitable diagnostics required to monitor the shot-to-shot operation of plasma structures and a complete set of instrumentation for the electron injector and laser plasma stage.

EuPRAXIA is the important intermediate step between proof-of-principle experiments and ground-breaking, ultra-compact accelerators for science, industry, medicine or the energy frontier. The design study was endorsed by the European Steering Group on Accelerator R&D (ESGARD) and developed with support from the EuroNNAc network. It aims at establishing a revolutionary design of a plasma-based accelerator with superior beam quality. The study shall help put this new type of particle accelerator on the roadmap for future science facilities with a significantly reduced footprint and hence much lower costs.