Along the right lines: Germany's niobium accelerator will lead research on the Higgs boson. Credit: DESY

Physicists have chosen the technology that will be used in the next generation of particle collider, an international experiment that hopes to study the particle thought to endow all others with mass.

The collider will use superconducting technology rather than copper coils, the International Committee for Future Accelerators decided on 20 August. The move, which comes after years of debate, means that hundreds of scientists in the United States and Japan, who have been working on the more traditional copper devices, must refocus their efforts.

Support for an international linear collider has been building over the past four years. The machine would smash together electrons and positrons, their antimatter equivalent, at enormous energies. This could generate the elusive Higgs boson, which theory predicts interacts with other subatomic particles to give them mass.

“You can think of the linear collider as a precision microscope,” says Philip Burrows, a physicist at Queen Mary, University of London. “It is a tool that will allow us to really pin down the properties of the Higgs.”

Two technologies have been front runners from the outset. Researchers at DESY, the German national research centre for particle physics in Hamburg, have promoted a design that uses superconducting niobium to create the huge electric fields for accelerating electrons and positrons (see Nature 410, 397; 200110.1038/35068676). A rival system, which uses copper coils, was developed at KEK, the high-energy accelerator research organization in Tsukuba, Japan, and at the Stanford Linear Accelerator Center (SLAC) in California.

“This was a really difficult decision,” says Barry Barish, head of the technical team charged with reviewing the two proposals. “Both technologies had their pluses and minuses.” Copper coils, for example, are capable of accelerating the particles over a shorter distance, but the superconducting technology would use less energy. In the end, Barish says, the team settled on the superconducting technology for a variety of different reasons, including its ability to create beams with a higher density of particles, resulting in an increased collision rate.

The move is likely to help DESY, which has struggled in recent months to get funding from the German government for a smaller prototype machine. But it will also force researchers at SLAC and KEK, which until now have devoted millions of dollars to developing copper technologies, to change direction quickly. Still, the director of SLAC, Jonathan Dorfan, says: “Much of the progress will be able to be redirected.”

With the technology chosen, Barish says, the international community will start designing the machine, and hope to deliver a preliminary blueprint by 2007. Although the cost of the machine is not yet known, Barish estimates that it will be “billions of dollars”.