The Advanced Light Source (ALS) is a specialized particle accelerator that generates bright beams of x-ray light for scientific research. Electron bunches travel at nearly the speed of light in a circular path, emitting ultraviolet and x-ray light in the process. The light is directed through about 40 beamlines to numerous experimental endstations, where scientists from around the world (“users”) can conduct research in a wide variety of fields, including materials science, biology, chemistry, physics, and the environmental sciences. The experimental techniques in use at the ALS fall into three broad categories:
- Spectroscopy -These techniques are used to study the energies of particles that are emitted or absorbed by samples that are exposed to the light-source beam and are commonly used to determine the characteristics of chemical bonding and electron motion.
- Microscopy/imaging - These techniques use the light-source beam to obtain pictures with fine spatial resolution of the samples under study and are used in diverse research areas such as cell biology, lithography, infrared microscopy, radiology, and x-ray tomography.
- Scattering/diffraction - These techniques make use of the patterns of light produced when x rays are deflected by the closely spaced lattice of atoms in solids and are commonly used to determine the structures of crystals and large molecules such as proteins.