Operating a cold space accelerator

An accelerator in California operates at temperatures close to absolute zero to generate 1 million X-ray pulses per second.

The tunnel houses the LCLS-II machine.

The SLAC National Accelerator Laboratory's superconducting particle accelerator at a depth of 9 meters below Menlo Park, California, was cooled to -271 degrees Celsius, just a few degrees above the coldest possible temperature in The universe is absolute zero (- 273.15 degrees Celsius). This extreme cold state is part of an upgrade to the Linac Coherent Light Source X-ray free-electron laser (LCLS) or LCLS-II, which can propel electrons at speeds close to the speed of light. Scientists will use the machine to study rare chemical events, biomolecules, quantum mechanics and complex materials used in computers.

Once the upgrade is complete, the LCLS-II will be able to generate X-ray pulses 10,000 times brighter than its predecessor, at a rate of 1 million pulses per second. This can only happen in the extreme cold of the accelerator, according to a statement from the laboratory.

In an earlier version of the LCLS, which began operating in 2009, electrons accelerated inside a 0.8-kilometer copper tube at room temperature, so the machine could only generate up to 120 x-ray pulses. /second. Instead, the new system consists of 39 cryogenic accelerometers with niobium metal chambers, all surrounded by a cooler. When the niobium cavities reach a temperature of -271 degrees Celsius, they become superconducting. That state eliminates resistance, so electrons can travel at extremely high speeds.

"In just a few hours, the LCLS-II will produce more X-ray pulses than conventional lasers produce over its entire lifespan," said Mike Dunne, director of the LCLS. "Data that once took months to collect can be generated in minutes. This will take x-ray science to the next level, paving the way for a wide range of research and accelerating the development of revolutionary technologies." culture to address some of the biggest challenges facing our society."

To develop the LCLS-II, SLAC partnered with Argonne National Laboratory, Lawrence Berkeley National Laboratory (Berkeley Lab), Fermilab, Thomas Jefferson National Accelerator Facility (Jefferson Lab), and Cornell University.