Results of magnetic measurements and field integral compensation for the elliptical multipole wiggler

A prototype of the Elliptical Multipole Wiggler (EMW) has been assembled, tested and tuned at the APS. This prototype has a period of 160 mm with 7 poles for the hybrid structure and 10 poles for the electromagnet part of the EMW. The hybrid structure of the EMW produces a vertical magnetic field of 0.83 T with K/sub y/=12 for a gap of 27 mm, and the electromagnetic structure provides a horizontal field change up to 100 Hz with a maximum field of 0.12 T (I=0.6 kA, K/sub x/=1.6). The current pulse has a trapezium-type shape with a switching time to change the current polarity of about 2 ms. The measurements and tuning were done for direct current (DC) mode and alternating current (AC) mode. Fine adjustment during the test at the NSLS X-ray ring using the BPMs and active correction system allowed to achieve about 1 /spl mu/m of beam distortion. It corresponds to the peak-to-peak variations during the time less than /spl plusmn/0.5 G-cm and /spl plusmn/100 G-cm/sup 2/ of the first and second horizontal field integrals respectively.