May Ling Ng, SLAC engineer, makes adjustments to the mirror restraints during a test of the holding system’s effect on mirror shape. These measurements are needed to maintain the flatness of the mirror within one atom over the entire one-meter length. Image: SLAC National Accelerator Laboratory
Scientists are installing new mirrors to improve the quality of the X-ray laser beam at the Department of Energy’s SLAC National Accelerator Laboratory.
The meter-long mirrors are the ultimate in flatness, smooth to within the height of one atom or one-fifth of a nanometer.
Right now, the mirrors are stored in a cleanroom to avoid dust and prevent damage. Engineers only handle the mirrors while wearing gowns, hairnets, masks and gloves. They’re testing the mirrors to see how they will respond to heat and mechanical stress while the beam is running. Both cause tiny deformations on the surface, and even changes as small as half a nanometer can cause big problems.
Five of these mirrors will be installed in LCLS by the beginning of next year and available for experiments in summer 2017. The new arrivals will join the 12 flat and curved mirrors that currently steer and focus light at LCLS, which is almost a mile long. Eventually, the upgraded mirror system will have a total of 28 mirrors.
Source: SLAC
