For more than five years now, a linear electron–positron collider big enough to explore the so-called tera-scale (collision energies of order 1012 electron volts or 1 TeV) has topped the wish list of the international community of particle physicists (see Physics Today, September 2004, page 49). Given the present state of accelerator technology, the collider's two face-to-face linacs would need a combined length of about 30 km to achieve a first-phase collision energy of 0.5 TeV. The cost of such a gargantuan facility dictates that the undertaking—from R&D and design, to construction, to operation—be thoroughly international from the start. Appropriately, the project carries the name International Linear Collider. The ILC is regarded as an essential complement to the Large Hadron Collider (LHC) ring at CERN, which should begin providing 14-TeV proton–proton collisions next year.
Now the ILC has its first estimated price tag, based on a...
