Science of SLAC | Ultrafast Electrons: A View into the Atomic World

Electrons are SLAC’s DNA. Since the lab’s birth they have generated the high-powered microwaves that propel particles down the two-mile-long linear accelerator. Electrons accelerated by the linac have been used to probe the world of elementary particles, and today they drive the LCLS X-ray laser. Now electrons are at the heart of SLAC’s newest initiative, Ultrafast Electron Diffraction and Ultrafast Electron Microscopy (UED/UEM), which will provide another tool for viewing the atomic world.

The goal of the initiative is to develop a UED/UEM facility that complements what we can see with LCLS and is uniquely capable of addressing Grand Challenge questions in chemistry, materials science, physics and biology. It will allow scientists to take snapshots of samples in atom-by-atom detail and reveal processes that take place in tens of femtoseconds, or quadrillionths of a second. To achieve this high level of resolution, the UED/UEM facility will take advantage of recent developments in high-brightness ultrafast electron sources, high-field magnets and electron detection. As a first step, SLAC has developed a UED setup at the Accelerator Structure Test Area (ASTA), with the goal of providing 1 million electronvolt (MeV), 100-femtosecond-scale electron pulses to support an ultrafast science program. The first round of ultrafast experiments with UED was recently completed.

Wang came to SLAC in December 2013 to lead the UED/UEM initiative after two decades at Brookhaven National Laboratory. At Brookhaven, he led the development of the Accelerator Test Facility (ATF) and did seminal work on ultrashort electron generation and characterization. He also served as linac section head for the National Synchrotron Light Source (NSLS) and as manager of the Source Development Lab (SDL). Under his leadership, the SDL became one of the world’s leading accelerator R&D facilities. Wang earned a PhD in physics from UCLA in 1992 and an undergraduate degree from Shaanxi Normal University in Xian, China.