65 segments of Insertion Device are now in operation around the ring, and can be operated freely from the beamlines (the acknowledgement by the Machine Control room has been removed). The prototype in-vacuum undulator installed in ID11 is now in routine user operation with a minimum gap down to 5 mm which corresponds to a maximum lifetime reduction of 15% in all filling modes. The success of the prototype has resulted in the launching of the production of four new in-vacuum undulators, each 2 m long. The installation of the first one is scheduled for July 2001.

A first Apple II undulator with an 88 mm period has been installed on ID8. Its effect on the beam has been analysed and corrected. A new quadrupole shimming technique has allowed the reduction of the horizontal tune shift variation by a factor 3 when the polarisation is flipped from right circular to right linear. Two more Apple II undulators were installed in December 2000 (see Figure 129).

Figure 129
Fig. 129: Apple II Structure.