N. David Mermin

Sep 18, 2023 | pubs.aip.org | David Kramer |Toni Feder |N. David Mermin |Laura Fattaruso

The world’s most powerful x-ray laser, the Linac Coherent Light Source II (LCLS-II) at SLAC National Accelerator Laboratory, officially produced its first x rays on 12 September. A $1.1 billion upgrade more than a decade in the making, the x-ray free-electron laser (XFEL) is now capable of firing 1 million x-ray pulses per second—8000 times as many as the first-generation LCLS, which began operation in 2009. Each pulse is 10 000 times as bright as those of the original LCLS.