The Accelerator Test Facility 2 (ATF2) is a scaled demonstrator system for final focus beam lines of linear high energy colliders. This paper describes the high resolution cavity beam position monitor (BPM) system, which is a part of the ATF2 diagnostics. Two types of cavity BPMs are used, C-band operating at 6.423 GHz, and S-band at 2.888 GHz with an increased beam aperture. The cavities, electronics, and digital processing are described. The resolution of the C-band system with attenuators was determined to be approximately 250 nm and 1 m for the S-band system. Without attenuation the best recorded C-band cavity resolution was 27 nm.
@article{arxiv.1301.5561,
title = {Cavity beam position monitor system for the Accelerator Test Facility 2},
author = {Y. I. Kim and R. Ainsworth and A. Aryshev and S. T. Boogert and G. Boorman and J. Frisch and A. Heo and Y. Honda and W. H. Hwang and J. Y. Huang and E. -S. Kim and S. H. Kim and A. Lyapin and T. Naito and J. May and D. McCormick and R. E. Mellor and S. Molloy and J. Nelson and S. J. Park and Y. J. Park and M. Ross and S. Shin and C. Swinson and T. Smith and N. Terunuma and T. Tauchi and J. Urakawa and G. R. White},
journal= {arXiv preprint arXiv:1301.5561},
year = {2013}
}