What is Synchrotron Radiation?

Synchrotron radiation (SR) is emitted from an electron traveling at almost the speed of light when its path is bent by a magnetic field. As it was first observed in a synchrotron in 1947, it was named "synchrotron radiation".

Generation of Synchrotron Radiation

Synchrotron radiation is emitted at a bending magnet or at an insertion device. The insertion device is comprised of rows of magnets with alternating polarity and is installed in a straight section of the electron orbit. There are two types of insertion devices, distinguished by magnetic field strength: the undulator and the wiggler.

• Bending Magnet: Stored electrons run on a circular orbit and emit synchrotron radiation with a continuous spectrum when they encounter the bending magnet.

Synchrotron radiation produced at a bending magnet

• Undulator: The electron beam wiggles with a small deviation angle. As a result, ultra-bright and quasi-monochromatic light is obtained by the interference effect.

Synchrotron radiation produced at an undulator

• Wiggler: The electron beam wiggles with a large deviation angle. As a result, bright and spectrally continuous light with short wavelengths is obtained.

General Features of Synchrotron Radiation

Synchrotron radiation has the following features:

• Ultra-bright
• Highly directional
• Spectrally continuous (Bending Magnet/Wiggler) or quasi-monochromatic (Undulator)
• Linearly or circularly polarized
• Pulsed with controlled intervals