What is a synchrotron light source?
A synchrotron light source is made up of several key components: a source of electrons, a linear accelerator, a booster synchrotron and a storage ring. Electrons are generated in the electron gun, and accelerated in bunches of several billion in the linear accelerator before continuing their journey into the booster synchrotron where they are further energised. Once the right energy is reached, the electrons are injected into the storage ring where several hundred bunches of electrons race around at just under the speed of light so that they give off light 10 billion times brighter than the sun. At various points around the storage ring, these electrons pass through specially designed magnets and emit brilliant synchrotron light. This light is channelled down to the experimental stations, which are called beamlines. Many experiments can run simultaneously making a synchrotron a high-throughput environment with the ability to support a large community of scientists.
What is a free-electron laser?
Free-electron lasers (FELs) are also accelerator-based light sources, utilising electrons to generate beams of light with unique properties. Unlike circular synchrotrons, FELS are based on a linear accelerating structure. The electron beam is passed through magnetic undulators up to 300 m long. These arrays of magnets can be manipulated to produce the required light for a given experiment. Through complex interactions between the photons and electrons in the undulator, the electrons arrange themselves into thin disks which emit light in a highly synchronised way. The resulting light from these minute electron disks is pulsed and laser-like. This enables the study of processes at the atomic scale across a range of timescales, reaching the femtosecond, which was previously inaccessible to researchers. Each FEL possesses a number of beamlines enabling research into physical and life sciences.