Field error compensation and thermal beam load in a superconductive undulator

During the last few years, prototypes of superconductive undulators have been built and tested. Measurements of the magnetic field showed that both the first and the second field integral are, as expected, not fully compensated and that a small but not negligible phase error exists. In order to compensate for these errors, electric shimming techniques are applied. Integral shimming is already part of the two 14 mm undulators under construction. The electric phase-shimming is still under investigation. At the end of this paper the thermal beam load for a small-gap superconductive undulator is estimated defining the layout of the cooling system.