"This is a major step towards future light sources based on laser-driven accelerators."

Following work conducted at the Central Laser Facility, an international collaboration led by the University of Michigan and Queen's University Belfast has developed a new diagnostic technique for measuring ultra-short particle beams. The research addresses a key challenge in developing compact alternatives to kilometre-long particle accelerators.

Current X-ray free-electron lasers (XFELs), which produce laser-like X-rays for imaging at the viral scale, require massive facilities stretching for kilometres. Laser wakefield acceleration (LWFA) offers the potential to create similar capabilities in devices small enough to fit on a laboratory bench.

LWFA works by focusing an intense, ultra-short laser pulse into plasma – matter where electrons and ions are separated.

The laser displaces electrons from ions, creating an electric field that causes electrons to oscillate in wave patterns behind the laser pulse, much like a surfer being pushed by the waves These waves can accelerate particles to high energies over much shorter distances than conventional particle accelerators.

However, measuring the resulting particle beams has proven challenging due to their extremely brief duration—lasting less time than it takes light to cross the width of a human hair.

The research team's solution involved using laser light to deflect particles by small amounts. Measuring these deflections, and analysing the laser field oscillations, enabled researchers to determine both the position and energy of individual electrons.

The diagnostic method represents a significant step towards making powerful XFEL light sources more accessible to universities and research institutions that cannot accommodate large-scale accelerator facilities.

Such compact devices could enable new research in structural biology, materials science and medical imaging.

Professor Rajeev Pattathil, Head of Novel Accelerators at STFC Central Laser Facility: "Laser driven plasma accelerators are maturing to a level where advanced light sources such as XFELs are being designed based on this technology. One of the prerequisites for this is to understand the temporal characteristics and energy of the accelerated electron bunches. Simultaneous measurement of these is important and using Gemini, the collaboration has come up with a diagnostic technique that is able to do this. This is a major step towards future light sources based on laser-driven accelerators."

This research demonstrates STFC's continued commitment to fostering the development of advanced scientific instrumentation and supporting the UK's position in accelerator science and technology.

See the published paper in Physical Review X.​​

News from: https://www.clf.stfc.ac.uk/Pages/herringbone-wave.aspx