Magnetic Performance of Insertion Devices at the Advanced Photon Source
Abstract
The Advanced Photon Source (APS) now has a total of 23 insertion devices (IDs). Over two-thirds are installed on the storage ring, including a 27-mm-period undulator, an 85-mm-period wiggler, a 16-cm-period elliptical wiggler, and many 33-mm-period undulators. All of the IDs were measured magnetically at APS and, in most cases, underwent a final magnetic tuning at APS. A particular concern was to minimize the various integrals of the field through the ID, including the higher-order integrated multipole moments, and to keep their variation with gap small. This minimizes the effect of an ID on the particle beam as the field of the ID is changed. Special shimming techniques to correct the magnetic field parameters in appropriate gap-dependent ways were developed and applied. Measurements of the particle beam motion as the field strength of each ID was changed throughout its range found that the closed orbit distortion was better than the requirement and agreed well with predictions based on magnetic measurement results.
- Publication:
-
APS Meeting Abstracts
- Pub Date:
- May 1997
- Bibcode:
- 1997APS..PAC..4C12M