A dynamic method for continuously measuring magnetic field profiles in planar micropole undulators with submillimeter gaps

Conventional techniques for measuring magnetic field profiles in ordinary undulators rely predominantly on Hall probes for making point-by-point static measurements. As undulators with submillimeter periods and gaps become available, such techniques will start becoming untenable, due to the relative largeness of conventional Hall probe heads and the rapidly increasing number of periods in devices of fixed length. In this paper a method is presented which can rapidly map out field profiles in undulators with periods and gaps extending down to the 100 μm range and beyond. The method, which samples the magnetic field continuously, has been used successfully in profiling a recently constructed 726 μm period undulator, and seems to offer some potential advantages over conventional Hall probe techniques in measuring large-scale undulator fields as well. (orig.)