AIP Digital Archive
Electrical Engineering, Measurement and Control Technology
Micropole undulators (wigglers) are undulators (wigglers) with submillimeter periods and are referred to, generically, as micropole insertion devices. Compared to ordinary insertion devices, whose period λu is typically ≥l cm, micropole devices have periods smaller by a factor f≤10. Therefore, the first-harmonic radiation emitted by a micropole undulator will have its photon energy Eγ increased by f and its spectral purity Δλ/λ by f, provided the total length of the undulator lu stays unchanged, and magnetic field errors, as well as the electron-beam emittance, are sufficiently small. Furthermore, to generate photons of the same Eγ as from the conventional device, the electron-beam energy Ee can be reduced by f 1/2 , resulting in significantly lower construction and operating costs. Radiative energy losses can be correspondingly diminished for the associated storage rings. In this paper we report on results recently obtained by us in the practical implementation and design of micropole undulators at the Stanford Synchrotron Radiation Laboratory (SSRL) and the Lawrence Livermore National Laboratory (LLNL). Based on our work, micropole undulators with f≤104 appear feasible at the present time.
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