The Advanced Photon Source (APS) is a 7 GeV storage ring light source that has been in operation for well over a decade. In the near future, the ring may be upgraded, including changes to the lattice such as provision of several long straight sections (LSS). Because APS beamlines are nearly fully built out, we have limited freedom to place LSSs in a symmetric fashion. Arbitrarilyplaced LSSs will drastically reduce the symmetry of the optics and would typically be considered unworkable. We apply a recently-developed multi-objective direct optimization technique that relies on particle tracking to compute the dynamic aperture and Touschek lifetime. We show that this technique is able to tune sextupole strengths and select the working point in such a way as to recover the dynamic and momentum acceptances. We also show the results of experimental tests of lattices developed using these techniques.

-The magnetic fields on the beam axis of helical undulators for the proposed International Linear Collider (ILC) gamma-ray production were calculated for undulator periods of 10 mm and 12 mm. The calculation assumed the use of low-carbon steel for the magnetic poles and a beam chamber outer diameter of 6.3 mm. Using NbTi superconducting coils at 4.2 K, the on-axis field for a 10-mm-period undulator was 0.62 T at the critical current density. The field for a 12-mm undulator period was 0.95 T, which gives a K value of 1.06. The K value for an 11-mm undulator with Nb 3 Sn superconducting coils was estimated to about 1.1.A transverse periodic helical magnetic field may be generated on the axis of a doublehelix coil with equal currents in opposite directions in each helix [1]. An ideal helical field may be expressed as with E as the electron beam energy, γ is the relativistic factor of the electron energy, and θ is the angle between the z-axis and the radiated photon beam direction. The deflection parameter K is defined as . For K = 1, the spectral power density of the photon beam is maximum at γθ =1 for a single electron [1]. This note calculates the fields on the undulator axis with a beam chamber outer diameter of 6.3 mm for periods of 10 mm and 12 mm to evaluate whether the listed K value could be achieved. Figure 1 shows a double-helix model coil for the low-carbon steel poles and the beam chamber. A double-helix superconducting (SC) coil with equal currents in opposite directions in each helix was inserted in between the steel coils for the field calculations. A ANL/APS/LS-311 4/13/06

No abstract

Rev. 1, November 25, 2009: Updated the fitted B eff in Tables 1 -3, and 5 to use two decimals in the fitted equation. Explained chosen gaps. Added clarifications in the text and added additional references. Edited by C. Eyberger for release as cleared document ANL/APS/LS-314; updated in ICMS.Rev. 0a, June 17, 2009: ICMS Initial Release (minor clarifications and corrections of typographical errors, added footnote "d" to Table 4).

No abstract