Electron Gun-Based Magnetic Probe

Abstract

Accurate magnetic field measurements are fundamental to the construction, testing, and certification of magnetic systems. Often, in high accuracy systems, the measurement technique and its implementation may involve a considerable effort. One such example of this type of system is undulators for light sources. Advanced undulators require several magnetic measurements at different stages during their construction. Every magnet block, composed of several magnetic poles, must be measured individually and sorted based on the magnetic moment results. There are two degrees of freedom for each pole. First, for tuning the vertical field, a pole may be moved, and, second, the local gap formed by a top and bottom pole may also be adjusted for vertical and horizontal field errors. Usually, undulators are assembled with a collection of periodic blocks surveyed to assess their accurate positions. The final process of fine-tuning the undulators requires the magnetic measurements of the whole assembly.