INSERTION DEVICES FOR BESSY-II

The high-brilliance synchrotron radiation source BESSY II will provide space for the installation of 14 insertion devices. At the time of wr iting (July 1997), eight insertion devices are funded. The first light for use by scientists will be available in January 1999. The undulato rs are designed for a scanning operation in parallel with the monochro mator. This modus requires tight tolerances concerning the drive syste m. The first insertion device to be installed, a U-49 undulator, has b een assembled and magnetically measured. The r.m.s. phase error is 2 d egrees. An endpole configuration using coils with less than 64 amp-tur ns makes the angular kick smaller than +/-3 mu rad over a gap range 15 -50 mm.