EMMA is a project to build a non-scaling 'fixed-field alternating gradient' (FFAG) accelerator at Daresbury Laboratory. Such an accelerator has never been built anywhere in the world and this radical challenge has been financed by the joint Research Councils Basic Technology fund.
FFAGs accelerate a beam of charged particles from low to high energy with particle orbits at different radii depending on the energy of the beam. In addition, the beam is compressed to be contained within a torus-shaped vacuum chamber (as with a synchrotron) and an FFAG is thus much more compact than a cyclotron. Together with other attractive properties this suggests a range of potential applications including charged particle cancer therapy, accelerator driven reactors and particle physics applications e.g. neutrino factories.
EMMA is a proof-of-principle project.
A FFAG accelerator has never been built anywhere in the world.
The EMMA focussing magnets have a standard quadrupole geometry but bending is achieved by offsetting the beam horizontally. Their extremely short length results in 'end effects' becoming dominant, and their positioning in closely spaced pairs around the ring produces non-trivial interactions.
Full 3D modelling has been necessary from the outset to make sure a beam can be successfully injected, transported around the machine, accelerated from 10MeV up to 20MeV, and extracted.
Funding for the EMMA project was granted to a UK consortium (CONFORM) from April 2007. This includes design study resources for a second ring, PAMELA, that extends the concept to a proton accelerator specification suitable for therapy. ASTeC also participates in this part of the project. The CONFORM grant provides funding until April 2011.