Loss of precision in resonant beam position monitors due to finite Q

Author

Sladen, J.P.H. ; Wuensch, W.

Author_Institution

CERN, Geneva, Switzerland

fYear

1993

fDate

17-20 May 1993

Firstpage

2346

Abstract

The performance of resonant beam position monitors is limited in part by the presence of a symmetrical (common mode) excitation of the cavity. Due to finite Q, a centred beam will give a non-zero output at the observation frequency. This interference is analysed and general expressions are given for the electrical and magnetic spectral densities, split into the wanted resonant term and the “broad-band” unwanted signal, for a cavity with arbitrary shape. This analysis is particularly relevant to beam position monitor studies for the CERN linear collider (CLIC), where very precise measurement of transverse beam position is required. It is shown that a common mode position error of under 1 μm is obtainable from a high Q 33GHz pill-box, even prior to the use of any external difference-taking elements

Keywords

beam handling equipment; cavity resonators; electron accelerators; linear accelerators; particle beam diagnostics; 33 GHz; CERN linear collider; CLIC; broad-band signal; centred beam; common mode position error; electrical spectral densities; external difference-taking elements; finite Q; high Q 33GHz pill-box; magnetic spectral densities; nonzero output; observation frequency; precision loss; resonant beam position monitors; symmetrical common mode cavity excitation; transverse beam position; Colliding beam devices; Frequency; Genetic expression; Interference; Magnetic analysis; Magnetic resonance; Particle measurements; Position measurement; Shape; Signal analysis;

fLanguage

English

Publisher

ieee

Conference_Titel

Particle Accelerator Conference, 1993., Proceedings of the 1993

Conference_Location

Washington, DC

Print_ISBN

0-7803-1203-1

Type

conf

DOI

10.1109/PAC.1993.309317

Filename

309317