Science
Japanese system for seeing very small objects

SACLA Magnifies World's Smallest Object - X-ray Free Electron Laser

Burgess COMMENTARY

Peter Burgess

SACLA Magnifies World's Smallest Object - X-ray Free Electron Laser

SACLA, pronounced さくら (Sa-Ku-Ra) is the free-electron laser, or X-FEL in Japan, embedded in the SPring-8 accelerator and synchrotron complex.[1] Operational since 2011, it is the brightest X-ray source of the world.

What is X-ray Free Electron Laser?

To gain a full understanding of physical and biological phenomena, we need to look at the way atoms and molecules are structured and function, and how the electrons within them move. Being able to directly observe the arrangement and movements of these atoms and electrons would enable us to develop drugs for hard-to-cure diseases and treat harmful chemicals that damage the environment, thus contributing to human welfare.

X-rays are one key to making this happen. Discovered in 1895 by Willhelm Roentgen, x-rays are most well-known today for their use in hospitals. X-rays are light with a much shorter wavelength than visible light. In addition to medical applications, they can be used to examine microstructures at the atomic and molecular level. SPring-8, a synchrotron facility, is one of the world’s most powerful x-ray sources, but it is still not powerful enough to allow us to see the extremely rapid movements of atoms and molecules.

Lasers are another key to this goal. Researchers realized that if they could make a laser, which emits a very powerful burst of concentrated light, emit x-ray light, they could use it to observe the instantaneous movement of electrons and molecules. Lasers emit coherent light (with the waves of the light matching one another), and can be used for a number of optical technologies. X-ray lasers, however — while a longtime dream — have in the past been beyond the reach of technology of the day.

Unlike traditional methods based on the light-emitting properties of materials, the building of an x-ray laser requires accelerating electrons to high energies, manipulating their motion, and using the light emitted during the process of acceleration. Since it is free electrons removed from atoms that are used to produce the x-ray laser, this new type of device is called an X-ray Free Electron Laser, or XFEL. This laser makes it possible for us to observe atoms and molecules in real time.

We'll be introducing the 700 meter long X-ray laser facility SACLA, where things that are a billionth of a millimeter become visible. This feat is made possible with a powerful X-ray laser. The electrons are drastically accelerated until a light that is a hundred million times a hundred million times brighter than sunlight is produced. This makes it possible for scientists to observe things that were once limited to speculation. A collection of Japan's original and sophisticated technologies was used to create SACLA, a giant microscope that can reveal objects on the atomic level.