Modelling and characterisation of a micropole undulator with a 726μm period

Micropole undulators (i.e. undulators with submillimetre periods) have the potential for fundamentally transforming the current state of synchrotron radiation technology. For example, brightness and photon energy resolution exceeding those of conventional insertion devices will become available on storage rings of much lower energy than those in present use. The authors report on the measurement and modelling of a recently built prototype device consisting of thirty-five 726 mu m periods. This device was constructed on the basis of a novel approach that, coupled with the particular configuration of its permanent magnet and soft steel elements, constitutes a design scheme that will eventually enable much shorter periods to be reached.