The Advanced Photon Source (APS) is currently in the preliminary design phase for the multi-bend achromat (MBA) lattice upgrade. Beam stability is critical for the MBA and will require long term drift, defined as beam motion, over a seven-day timescale to be no more than 1 micron at the insertion device locations and beam angle change of no more than 0.25 micro-radian. Mechanical stability of beam position monitor (BPM) pickup electrodes mounted on insertion device vacuum chambers place a fundamental limitation on long-term beam stability for insertion device beamlines. We present the design and implementation of prototype mechanical motion system (MMS) instrumentation for quantifying this type of motion, specifically in the APS accelerator tunnel and experiment hall floor under normal operating conditions. The MMS presently provides critical position information on the vacuum chamber and BPM support systems. Initial results of the R&D prototype systems have demonstrated that the chamber movements far exceed the long-term drift tolerance specified for the APS Upgrade MBA storage ring.
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