Abstract
The Advanced Photon Source Upgrade (APS-U) project is progressing from its final design phase into production for the future 6 GeV, 200 mA, multi-bend achromat upgrade of the existing APS and so too is the storage ring vacuum system design. The vacuum system will include over 2500 custom vacuum chambers ranging from 50 mm up to 2.5 meters in length and typically featuring APS-U’s standard narrow 22 mm inner diameter aperture. The vacuum system must maintain UHV for the circulating electron beam while the water-cooled vacuum components intercept significant synchrotron radiation loads. The scope of NEG coatings was increased to 50% of the length of the vacuum system to ensure the vacuum system conditions quickly and pressure requirements can be met.
Vacuum chamber locations, lengths, and materials were settled in the preliminary design phase but significant effort was required to work through local and system level design challenges. Local challenges include detailing robust welds and brazes on the thin-walled vacuum chambers and performing detailed FEA thermal/stress analysis for vacuum components, which intercept large synchrotron radiation heat loads. System level challenges include using CAD to design within the complex machine assembly, networking components to utilities, and planning for installation and alignment. This presentation will highlight the major design challenges and solutions for the storage ring vacuum system and plans for production and installation.