Cavity BPM system for ATF2

Abstract

In this paper we summarise our 2-year experience operating the Cavity Beam Position Monitor (CBPM) system at the Accelerator Test Facility (ATF) in KEK. The system currently consists of 41 C and S-band CBPMs and is the main diagnostic tool for the ATF2 extraction beamline. We concentrate on issues related to the scale of the system and also consider long-term effects, most of which are undetectable or insignificant in smaller experimental prototype systems. We consistently demonstrate sub-micron BPM resolutions and show the route for achieving weekto- week scale drifts of an order of 1%.