The EuPRAXIA design study has shown that plasma acceleration provides a viable alternative to established accelerator technologies.

Accelerator facilities have many applications in medicine and industry, including cancer therapy, medical diagnostics, cargo inspection and food sterilisation, but their size and cost currently restrict access to this powerful technology.

The accelerator designed by EuPRAXIA will use lasers or electron beams to propel electrons forward on a wave of plasma. The result will be a much smaller, more affordable accelerator that uses accelerating gradients up to 1,000 times higher than what can be achieved with radio frequency technology.

The results could enable the installation of future accelerators in university campuses, hospitals and factories, as well as opening up opportunities for new applications.

Professor Dino Jaroszynski, of Strathclyde’s Department of Physics and the director of the Scottish Centre for the Application of Plasma-based Accelerators (SCAPA), is a partner in the project. He said: “Development of these next-generation and ultra-compact accelerators is extremely important in that they will eventually take their place alongside ’conventional’ accelerators that are at least 1000 times larger.

“This is an enabling technology that will lead to a wide range of new applications, which will eventually feed into the economy and the health of nations. This is because of their unique characteristics and also their compactness, which will make them less expensive and more widely available.”

Strathclyde led the first UK Basic Technology project to develop this technology in the early 2000s, known as ALPHA-X (Advanced Laser Plasma High-energy Accelerators towards X-rays). The ALPHA-X project, which also involved Imperial College, the University of Oxford and the Rutherford Appleton Laboratory, made a major advancement in 2004 when it first demonstrated controlled acceleration. This pioneering advance was published in Nature in 2004 and was part of a series of publications which has become known as the “Dream Beam” papers.

Professor Jaroszynski said: “The Strathclyde group was first to propose developing a free-electron laser based on this laser-plasma technology in 2002, which is now one of the major objectives in EuPRAXIA. We went on to demonstrate a compact synchrotron source based on the laser-plasma accelerator in 2008, which was published in Nature Physics, and constructed the first synchrotron beamline based on a laser-plasma accelerator. We are now very pleased to have also contributed to the EuPRAXIA project.

Strathclyde’s involvement in EuPRAXIA includes developing novel radiation sources and attosecond sources based on laser-plasma accelerators and also beam-drive plasma wakefield accelerators.”

The foreseen electron energy range of 1-5 GeV (giga-electron volts) and its performance goals will enable versatile applications in various domains, such as compact free-electron lasers, compact sources for positron, table-top test beams for particle detectors and deeply penetrating X-ray and gamma-ray sources for material testing.

An area of particular interest will be the ability to produce ultra-short pulses of electrons and photons that are highly relevant to studying biological and chemical processes.

Over the last four years, the scientists have evaluated nine different scenarios for creating high-quality beams using plasma acceleration. In the end, several highly performing accelerator designs have been found as an optimal way forward and will be integrated into multiple beamlines using laser- and electron-beam-driven plasma wakefield acceleration.

Once a factor-3 reduction in facility size has been demonstrated by EuPRAXIA, a miniaturization process towards even more compact designs will be pursued. A reduction factor of 10 and even 20 for the accelerator itself seems feasible at high beam energy.

The design of EuPRAXIA includes a facility for pilot users, so that researchers can explore the full potential of the accelerator for the first time.

The EuPRAXIA design is the work of leading scientists from 16 laboratories and universities from five European countries, with a further 25 partners globally. It has been coordinated by DESY (Deutsches Elektronen-Synchotron) and funded by the EU’s Horizon 2020 programme. Participation in EuPRAXIA provides a unique opportunity to be at the forefront of research which will revolutionise the use of accelerators.