Undulator

A device used in synchrotron radiation facilities

Overview

Diagram of an undulator showing the periodic magnetic structure.

An undulator is a periodic structure of magnets used in synchrotron radiation facilities to produce highly collimated and intense beams of electromagnetic radiation. These devices are essential components in free-electron lasers and synchrotron light sources, where they are used to generate coherent light across a wide range of wavelengths, from infrared to X-rays.

Principle of Operation

Undulators work by forcing a beam of relativistic electrons to undergo a series of oscillations as they pass through a periodic magnetic field. This oscillatory motion causes the electrons to emit radiation at specific wavelengths, determined by the undulator equation. The emitted radiation is highly collimated and can be tuned by adjusting the magnetic field strength or the energy of the electron beam.

Types of Undulators

There are several types of undulators, including:

• Planar undulators: These have a linear arrangement of magnets and produce linearly polarized light.
• Helical undulators: These have a helical arrangement of magnets and can produce circularly polarized light.
• Elliptical undulators: These can produce light with variable polarization states.

Applications

Undulators are used in a variety of scientific and industrial applications, including:

• X-ray crystallography
• Material science
• Biological imaging
• Medical imaging

Advantages

Undulators offer several advantages over other types of radiation sources, such as:

• High brightness and intensity
• Tunable wavelength
• Coherent radiation

Related pages

• Synchrotron radiation
• Free-electron laser
• Magnetic field

References

• "Undulator." Wikipedia, The Free Encyclopedia. https://en.wikipedia.org/wiki/Undulator
• "Synchrotron Radiation and Free-Electron Lasers." Journal of Synchrotron Radiation, vol. 25, no. 1, 2018, pp. 1-10.