ANL, Argonne, Illinois, USA
IIT, Chicago, Illinois, USA
A number of research and development activities are underway at Argonne National Laboratory to build confidence in the designs for the storage ring vacuum system required for the Advanced Photon Source Upgrade project (APS-U) [1]. The predominant technical risks are: excessive residual gas pressures during operation, insufficient beam position monitor stability, excessive beam impedance, excessive heating by induced electrical surface currents, and insufficient operational reliability. Present efforts to mitigate these risks include: building and evaluating mock-up assemblies, performing mechanical testing of chamber weld joints, developing computational tools, investigating design alternatives, and performing electrical bench measurements. Status of these activities and some of what has been learned to date will be shared.
*B. Stillwell et al., Conceptual Design of a Storage Ring Vacuum System Compatible with Implementation of a Seven Bend Achromat Lattice at the APS, in Proc. IPAC'14, Dresden, Germany, 2409-2411.
ANL, Argonne, Illinois, USA
Fermilab, Batavia, Illinois, USA
BNL, Upton, Long Island, New York, USA
Extensive prototyping of storage ring magnets is ongoing at the Advanced Photon Source (APS) in support of the APS Multi-Bend Achromat upgrade (APS-U) project. As part of the R&D activities 4 quadrupole magnets with slightly different geometries and pole tip materials, and one sextupole magnet with vanadium permendur pole tips were designed, built and tested. Magnets were measured individually using a rotating coil and a Hall probe for detailed mapping of the magnetic field. Magnets were then assembled and aligned relative to each other on a steel support plate and concrete plinth using precision machined surfaces to gain experience with the alignment method chosen for the APS-U storage ring magnets. The required alignment of magnets on a common support structure is 30 micron rms. Measurements of magnetic field quality, strength and magnet alignment after subjecting the magnets and assemblies to different tests will be presented.
ANL, Argonne, Illinois, USA
The Advanced Photon Source is in the process of developing an upgrade (APS-U) of the storage ring from a double-bend to a multi-bend lattice. A swap-out injection is planned for the APS-U lattice to keep a constant beam current and accommodate small, dynamic aperture. A septum magnet that has a minimum thickness of 2 mm with an injection field of 1.06 T has been designed. The stored beam chamber has an 8 mm x 6 mm super-ellipsoidal aperture. The required total deflecting angle is 89 mrad with a ring energy of 6 GeV. The magnet is straight, but is tilted in yaw, roll, and pitch from the stored beam chamber in order to meet the swap out injection requirements for the APS-U lattice. In order to minimize the leakage field inside the stored beam chamber, four different techniques were utilized in the design. As a result, the horizontal deflecting angle of the stored beam was held to only 5 μrad, and the integrated skew quadrupole inside the stored beam chamber was held to 0.09 T. The detailed techniques that were applied to the design, the field multipoles, and the resulting trajectories of the injected and stored beams are reported.