Sun, X. Lill, R.M. Stillwell, B.K. JACoW Geneva, Switzerland 978-3-95450-192-2 10.18429/JACoW-IBIC2017-TUPCF03 English 199-202 TUPCF03 ion pick-up simulation storage-ring vacuum Contribution to a conference proceedings 2018 2018-03 https://doi.org/10.18429/JACoW-IBIC2017-TUPCF03 http://jacow.org/ibic2017/papers/tupcf03.pdf The Advanced Photon Source (APS) is currently in the preliminary design phase for a multi-bend achromat (MBA) lattice upgrade. Beam stability is critical for the MBA and will require roughly 570 rf beam position moni-tors (BPMs) to provide the primary measurement of the electron beam trajectory through the insertion device (ID) straight sections and in the storage ring arcs. The BPM assembly features 8 mm diameter pickup electrodes that are welded to a stainless steel chamber and integrated shielded bellows both upstream and downstream of the chamber to decouple the BPM electrodes from mechani-cal motion of adjacent chambers. The design, simula-tions, and prototype test results will be presented.