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The current design of the Advanced Photon Source Upgrade (APS-U) project is a multi-bend achromat (MBA) lattice, which incorporates three-pole wigglers as radiation sources for the bending magnet beamlines. They are located in the short section between the M4 dipole and Q8 quadrupole magnets. Due to space constraints, a hybrid permanent magnet design is necessary to provide the required magnetic field strength. A three-pole wiggler with a flat peak field profile along the beam axis was designed to enhance the photon flux and flatten the transverse flux density distributions. The magnetic peak field at the center pole reached 1.08 Tesla for a magnetic gap of 26 mm. The maximum power density, integrated over all vertical angles, is 3.1 W/mm², which is substantially higher than that of the existing bending magnets at the APS (0.86 W/mm²). Detailed designs of the three-pole wiggler is presented, including calculated spectral-angular flux distributions. [ABSTRACT FROM AUTHOR]

The Advanced Photon Source (APS) is a third-generation synchrotron with major emphasis on insertion device (ID) sources. In the storage ring there are 35 straight sections, each about five meters in length, for possible insertion devices. Most of the insertion devices at the APS are 2.4 meters long. Currently there are 27 undulators installed in 25 straight sections. Twenty-two of the undulators are the original design fabricated by STI Optronics, which used two motors, one for each end of the device. A synchronizing mechanism between the upper and lower magnetic arrays was also used at each end. Recently, the APS has designed a new gap-separation mechanism for all new undulators. The new design is based on four independent motors, one driving each end of each magnetic array of the device. The control system of choice at the APS is EPICS. The control system is designed to be transparent to the user of the beamline who routinely operates the device. The differences between the two-motor and the four-motor versions of the ID control system are performed at low levels and are transparent. All devices have feedback and safeguard redundancy in the form of linear and rotary encoders and multiple-stage limit switches. This paper will discuss in detail the design philosophy and the implementation of the four-motor insertion device control system. This control system has been in operation for about three years. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]