Antimatter!

摘要

The call comes in from the control room. Stanford University's particle accelerator―one of the largest machines on Earth―has been shut down because of a failed magnet. This is bad news for the scientists I have traveled across the continent to see: Their experiment was designed to run 24 hours a day and the disruption will cost them reams of precious data. But me, I'm thrilled. Normally, the innards of the radiation-spewing accelerator are off-limits. But idle, it poses no danger. I glance at Stew Smith, a physicist leading the experiment, and he asks if I would like to go inside. Access. I'm about to enter the heart of the cavernous, 2-mile-long accelerator. I'm about to see the place where matter meets antimatter billions of times a second. One security checkpoint later, I don my hard hat and radiation badge and step into a building whose bland industrial features belie the tumult that goes on inside. In a procedure that reminds me of a nuclear missile launch sequence, Smith and I announce ourselves to a faceless voice coming from a speaker above our heads and then, using one key per person, sequentially unlock the main access door. Inside, ringed by a tangle of high-speed data lines, racks of circuitry, and multiple steel catwalks, is the giant detector, the heart of the Stanford Linear Accelerator, or SLAC, in Menlo Park, California.