Synchrotron radiation from electron storage rings

Abstract

Abstract Description of the electron beam At any point in the storage ring, an electron can be described in terms of its position, its direction of motion, and its energy. It is convenient to measure these quantities relative to the ideal electron orbit. If we imagine a coordinate system as shown in Fig. 9.1 then at any given instant, any individual electron will be located at a point (x, y) in an x−y plane which intersects the ideal orbit at a point P, located at a distance s measured along the ideal orbit from some arbitrary starting point s0. This coordinate frame must be imagined as moving around the ideal orbit, so that, relative to an observer in the laboratory, the coordinate axes s and x(which with y, form a set of mutually perpendicular coordinate axes) change their direction in space as the electron moves around the storage ring. The advantage of this coordinate system is that it enables us to describe the movement of the electron in position and time relative to the ideal orbit as though the ideal orbit were a straight line.