Technology Development for Short-period Magnetic Undulators

Methodsfor manufacturing and characterizing permanent-magnet-based short-period undulators are presented. Two fabrication methods, differing by the dimension range of their magnetic period, are described: the mini-undulator, with magnetic periods ranging from 1 mm to 200 μm, fabricated by laser micromachining bulk permanent magnets; and the micro-undulator, with magnetic periods from 200 μm to 10 μm, fabricated by electroplating or sputtering a hard magnetic material onto silicon. The undulator gaps vary from 500 μm down to tens of microns, corresponding to the reduction of the magnetic period. Undulator peak magnetic fields can reach up to 0.7 T while maintaining a reasonable undulator gap. Using these short-period undulators, high-photon-energy radiation can be generated at lower electron beam energies compared to current state-of-the-art undulators.