1 - Synchrotron radiation sources

Abstract

Synchrotron radiation is a very bright, broadband, polarized, and pulsed source of light extending from the infrared to the x-ray region. It is an extremely important source of vacuum ultraviolet radiation. Brightness is defined as flux per unit area per unit solid angle and is normally a more important quantity than flux alone, particularly in throughput-limited applications, which include those in which monochromators are used. Synchrotron radiation covers the entire electromagnetic spectrum from the infrared region through the visible, ultraviolet, and into the x-ray region up to energies of tens of kilovolts. If the charged particles are of low mass, such as electrons, and if they are traveling relativistically, the emitted radiation is very intense and highly collimated, with opening angles of the order of 1 mrad. In electron storage rings, there are three possible sources of synchrotron radiation—dipole (bending) magnets; wigglers, which act as a sequence of bending magnets with alternating polarities; and undulators, which are also multiperiod alternating magnet systems, but in which the beam deflections are small, resulting in coherent interference of the emitted light.