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SPARTA (ERC StG): Developing multistage plasma-based accelerators

Particle accelerators are used for everything from research to cancer treatment, but are very costly. Plasma-based acceleration promises to drastically reduce this cost compared to conventional technology. The SPARTA project aims to solve two major remaining challenges in plasma acceleration: connecting multiple accelerator stages; and increasing the stability.

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Plasma-based accelerator, using a plasma (blue-white) only 50 mm long and 1.5 wide. A "bunch" of electrons (orange; to the right in the inset) is used to drive strong electric fields that rapidly accelerate a trailing electron bunch (to the left in the inset). This accelerator is 10–1000 times smaller than a conventional particle accelerator.

About the project

SPARTA (Staging of Plasma Accelerators for Realizing Timely Applications) is an ERC-funded, 5-year project for developing new particle-accelerator technology at the Department of Physics, in collaboration with international partners.

Plasma-based accelerators, which can accelerate electrons to high energy in a very short distance (e.g., 1 GeV in 1 cm) promise more compact and much cheaper particle accelerators, but come with new challenges. Two major issues are:

Connecting multiple plasma-accelerator modules, or stages, required to reach high energy (100 GeV or higher)—the electrons must be re-focused between stages without loss of "beam quality";
Avoiding plasma instabilities and reducing the extremely tight tolerances (sub-micrometer/femtosecond-level).

Image may contain: Automotive lighting, Automotive design, Bumper, Automotive exterior, Gadget. — Plasma lens: ideal for focusing electrons.

The SPARTA-project will test two new ideas that may solve these problems:

Non-linear plasma lenses, an upgraded version of so-called plasma lenses, that promise "perfect" focusing between accelerator stages;
Self-correction mechanisms arising from use of multiple stages, that stabilize the acceleration without external control.

If these solutions can overcome the problems, plasma accelerators can finally deliver electrons beyond the 100 GeV-level; the highest ever. As a first application—a "low-hanging fruit" of sorts—is proposed to be an experiment in strong-field QED (quantum electrodynamics), where an extremely powerful laser pulse collides with a high-energy electron.