Fermilab Today Wednesday, June 27, 2007

Meet EMMA, an accelerator of Many Applications

EMMA instrument experts Gianni Tassotto, Carol Johnstone, Manfred Wendt (experiment head) and Jim Crisp.

An international group of researchers is working on a new kind of particle accelerator that has exciting possibilities for cancer treatment, materials research and generating greener electricity by driving nuclear reactors that would produce less nuclear waste. The accelerator would use a continuous, rather than an alternating, current to power the accelerator's magnets, making it a hybrid between a cyclotron and a synchrotron. The first prototype, called "EMMA," for Electron Model with Many Applications, will be built in Daresbury, England for 16.6 million dollars. It is expected to be complete in 2010.

Roger Barlow of the University of Manchester is heading up EMMA's development in collaboration with 19 participants from 11 institutions. "EMMA is opening a whole new range of possibilities," said Barlow. "It's a long-shot, but it could even lead the way to accelerator-driven nuclear reactors. The nuclear reaction would be safer, and it would generate significantly less nuclear waste." He added that the new technology will also be able to accelerate heavy particles, such as carbon ions, which are better at specifically targeting cancer cells during radiation therapy.

Fermilab physicist Carol Johnstone, first proposed this new type of accelerator in the late 1990s and worked with Shane Koscielniak, TRIUMF, to demonstrate the feasibility of the concept. The idea was further developed by an international consortium of scientists, including physicists from national labs and universities in the United States, the United Kingdom, Japan and France.

Johnstone was trying to find a cheaper way to accelerate beams of muons for a neutrino factory project, which would use muons to produce neutrinos. Muons are short-lived particles that would circle an accelerator for only a few turns, or microseconds. "I was thinking about muon acceleration and I realized it is so rapid that we don't have to maintain constant optics," she said.

Johnstone proposed a simple accelerator with minimal beam optics equipment. Her solution, called a non-scaling Field Fixed Alternating Gradient allowed the accelerator to be much simpler and more cost-effective than conventional approaches. "It was unlike anything we had ever tried before," she said. The resulting design has the properties of a synchrotron (such as the Tevatron), yet it is more compact and less expensive and it has the high beam current capability of a cyclotron, a type of accelerator often used for cancer treatment in hospitals.

By 2000, institutions worldwide were collaborating to develop the first non-scaling FFAG prototype, called EMMA. This summer, Fermilab and the Accelerator Science and Technology Centre in the U.K. are signing a Memorandum of Understanding. Johnstone and other Fermilab physicists and engineers are working on EMMA and also collaborating on a new medical version of the non-scaling FFAG accelerator, which will be called PAMELA. Working with the DOE, Johnstone recently submitted a patent on a new version of the NS-FFAG that has great potential for cancer treatment applications.

"I am very excited about the applications for greener energy and cancer therapy," said Johnstone. "As a field, I think we have a moral and ethical responsibility to apply our inventions and make the world better."

-- Siri Steiner

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