Cavity BPM System Tests for the ILC Spectrometer

physics.ins-det

/ Authors

M. Slater, C. Adolphsen, R. Arnold, S. Boogert, G. Boorman, F. Gournaris, M. Hildreth, C. Hlaing, F. Jackson, O. Khainovski

and 11 more authors

Yu. G. Kolomensky, A. Lyapin, B. Maiheu, D. McCormick, D. J. Miller, T. J. Orimoto, Z. Szalata, M. Thomson, D. Ward, M. Wing, M. Woods

/ Abstract

The main physics programme of the International Linear Collider (ILC) requires a measurement of the beam energy at the interaction point with an accuracy of $10^{-4}$ or better. To achieve this goal a magnetic spectrometer using high resolution beam position monitors (BPMs) has been proposed. This paper reports on the cavity BPM system that was deployed to test this proposal. We demonstrate sub-micron resolution and micron level stability over 20 hours for a $1\m$ long BPM triplet. We find micron-level stability over 1 hour for 3 BPM stations distributed over a $30\m$ long baseline. The understanding of the behaviour and response of the BPMs gained from this work has allowed full spectrometer tests to be carried out.