16 Mar 2012







Compact Linear Accelerator for Research and Applications

Conceptual Design Report available here

CLARA Front End and VELA beamlines description available here.

CLARA is an advanced electron accelerator test facility which we plan to upgrade to become a free electron laser (FEL) test bed in the future. The CLARA project that has three key objectives:

  • To be the European test bed for accelerator research and development. Bringing together international collaborations and investments to support the next big inspirational global science projects whilst increasing UK leadership and influence.
  • To enable the UK academic, industrial, and health sectors to develop new accelerator-based technologies, treatments, and frontier research for the benefit of the economy and society.
  • To pave the way for the UK to host an ambitious next-generation X-ray FEL light source user facility with world-leading capabilities that would advance the frontiers of knowledge across the physical an d life sciences and support UK industry.

CLARA, which is located within the Electron Hall at Daresbury, will be a 90 m long, low energy version of an advanced FEL light source. The underlying physics for the electron beam generation, acceleration and dynamics and the coherent light generation and manipulation via the FEL process are identical (and scalable) to that of European XFEL and SwissFEL, for example. CLARA will have a maximum electron energy of 250 MeV and will be able to generate FEL radiation down to 100 nm wavelength. CLARA is built in three phases.

CLARA.pngThe first phase of CLARA is already operational and has achieved a beam energy of 50 MeV and bunch charges of more than 250 pC. Since 2018, high brightness electron beams from this phase of CLARA have been successfully delivered to academic and industrial users to test innovative ideas in a wide range of areas. These included Very High Energy Electron (VHEE) beam radiotherapy, novel acceleration experiments such as plasma wakefield acceleration, dielectric wakefield acceleration, THz driven acceleration and deflection schemes and many more. All the experiments have been highly successful with the results published in peer reviewed journals.

The second phase of CLARA is being built off-line and will deliver the full design beam energy of 250 MeV at beam charges up to 250 pC at 100 Hz repetition rate. This phase includes a dedicated Full Energy Exploitation beamline (FEBE) to provide higher energy high brightness beam for a wide range of experiments including and beyond the experiments carried out on the first phase. Following extensive stakeholder engagement with users, the FEBE beamline has been designed to enable a broad range of novel experiments in an easily configurable arrangement with the possibility for full beam characterisation post experiment. The interaction of high-quality electron bunches with high power laser light is foreseen as a key component of FEBE exploitation. FEBE will represent the only UK-based research infrastructure capable of supporting experiments in several novel acceleration areas, including external laser wakefield acceleration (xLWFA) and particle-driven plasma wakefield acceleration (PWFA). The FEBE platform, combined with access to the major LWFA facilities at RAL (EPAC) and Strathclyde University (SCAPA) will provide UK research and innovation with a world-leading platform in novel acceleration. It is expected that this phase will be available to user experiments in 2023.

The third phase of CLARA includes a 100 nm Free Electron Laser and the decision to proceed with this phase is linked with the next steps of the UK XFEL project.  

Development of new accelerator technologies or techniques can only be demonstrated if they are tested on an actual accelerator. Progress globally is limited because such tests must be carried out on accelerators that are dedicated to other purposes, such as particle physics or X-ray production. This restricts the time available for accelerator R&D and the degree of risk and innovation which can be trialled, since the primary objective of these facilities is to serve their user communities. With or without UK XFEL, CLARA is already an excellent accelerator testbed which serves the academic and industrial accelerator communities. These bottlenecks can therefore be removed and rapid progress in R&D is now possible. Reconfigurations of the machine are permitted, and high risk-high reward technologies can be trialled safely. CLARA gives the UK accelerator community genuine leadership in accelerator R&D. The two UK accelerator institutes, which include seven of the leading universities active in accelerator research, are already contributing significantly to the ongoing development and exploitation of CLARA, including funding several PDRAs and PhD studentships, and they have ambitious plans for future R&D using the bright electron beam and FEL testbed.​

Contact: Bradley, Julie (STFC,DL,AST)