The most powerful pulse of X-rays ever reported has been produced at the SLAC National Accelerator Laboratory in California. In only 440 billionths of a billionth of a second, or attoseconds, it packed nearly a terawatt of power – a thousand times more than the average yearly output of a nuclear power plant.
“In the near term, it will be hard to do better,” says Agostino Marinelli at SLAC, who worked on the project.