national synchrotron light source ii

The first diffraction pattern from the brightest synchrotron light source in the world is here! The electrons whizzing around at nearly the speed of light at Brookhaven’s National Synchrotron Light Source II create a high-energy x-ray beam, which was steered toward a sample of sulfur-doped tantalum selenide just yesterday. When the beam hits the sample, the x-rays scatter off the atoms within the material, creating this gorgeous array of rings. 

This special compound has a strange characteristic: At low temperatures, electrons in both the pure tantalum selenide and sulfur-doped tantalum compounds spontaneously form into charge density waves, like ripples on the surface of a pond. These ripples have different wavelengths, and when they cross over one another, instead of canceling out electronic activity, they surprisingly create superconductivity – the pure lossless transfer of electricity.  

“It is like mixing red paint and white paint, and instead of getting pink you get blue after mixing,” said professor Simon Billinge, joint appointee with Brookhaven and Columbia University. Data from the X-ray Powder Diffraction beamline will help us understand how charge density waves in materials may lead to superconductivity. That’s super important for our nation’s energy future, but it also means we’ll have some more beautiful diffraction patterns to gaze at. Lucky us. 

Here at Brookhaven, we rang in the new year with a big milestone. Engineers at our new National Synchrotron Light Source II (the enormous silver ring building in the photo) began commissioning the accelerators and boosters  that will push electrons to very nearly the speed of light to produce x-rays and UV rays that scientists will use to explore all kinds of materials, from biological samples to battery cores. 

Late on December 31, our technicians turned on the light source. They fired the electron gun (a hot cathode in a vacuum that produces electrons), sped the electrons up in the linear accelerator, and then shot them around the half-mile ring in the wee hours of January 1. The electrons reached three billion electron volts, the maximum design energy of the new facility. 

In the coming year, we’ll be testing all the parts of the accelerators, and then we’ll be opening up the beamlines for some hard-core science!