DESY Laser Gets the Nod, Collider Bid Deferred

The German Electron Synchroton (DESY) in Hamburg recently received good news and not-so-good news in a single breath: On 5 February, Germany’s science ministry announced that it will ante up €337 million ($363 million), or half the cost of the lab’s proposed x-ray free electron laser (X-FEL), but that, at least for now, it will not commit to the lab’s ultimate goal of building a supercon-ducting electron—positron collider, a contender to become the world’s next-generation particle accelerator. Both projects got conditional endorsement last year from Germany’s national science council (see Physics Today, November 2002, page 24 ).

Because DESY had hoped to garner greater support for TESLA, its proposed TeV-Energy Superconducting Linear Accelerator, the government’s decision to defer is disappointing. “Some people took the announcement as bad news, others took it as good news,” says Allen Caldwell, a particle physicist from Columbia University and the Max Planck Institute for Physics in Munich. “But the realists say that, given the state of the economy in Germany—and everywhere else—it’s as much as could be expected for now.”

For his part, DESY Director Albrecht Wagner says “the outcome is very good. The decision provided the lab with a clear direction and perspective: Build the X-FEL, and keep going with the linear collider R&D.” Next, DESY needs to enlist international partners for the X-FEL and to sort out financial, design, and organizational aspects of the project.

Superconducting accelerator cavities are the backbone of the 1.4-km X-FEL and 33-km TESLA alike. “Going through the process of bringing something from the lab into industry is a major step,” says Wagner. “Clearly the linear collider will benefit from building the free electron laser.”

Meanwhile, collider designs being developed in the US and Japan would rely on “warm,” nonsuperconducting technology. But whichever technology is used, and wherever it is sited, the consensus is that the multibillion-dollar next-generation linear collider has to be an international project (see Physics Today, September 2001, page 22 ). Indeed, Wagner says Germany plans to participate in the next linear collider wherever it is sited, but that the government “felt that a unilateral German move might be counterproductive for the international negotiations.”

And whether or not TESLA ever gets built, the X-FEL secures DESY’s future. The X-FEL will provide femtosecond light flashes orders of magnitude more intense than today’s light sources, says Wagner. “This makes it an ideal stroboscopic lamp for rapid processes.” To be sure, research on the X-FEL would stray from DESY’s historic strength in particle physics and put more emphasis on condensed matter physics, plasma physics, chemistry, and biology.