Measurement of the beam´s trajectory using the higher order modes it generates in a superconducting accelerating cavity

Author

Molloy, S. ; Frisch, J. ; May, J. ; McCormick, D. ; Smith, T. ; Baboi, N. ; Hensler, O. ; Petrosyan, L. ; Eddy, N. ; Piccoli, L. ; Rechenmacher, R. ; Ross, M. ; Wendt, M. ; Napoly, Olivier ; Paparella, Rita C. ; Simon, Claire

Author_Institution

SLAC, Menlo Park

fYear

2007

fDate

25-29 June 2007

Firstpage

2642

Lastpage

2644

Abstract

It is well known that an electron beam excites higher order modes (HOMs) as it passes through an accelerating cavity. The properties of the excited signal depend not only on the cavity geometry, but on the charge and trajectory of the beam. It is, therefore, possible to use these signals as a monitor of the beam´s position. Electronics were installed on all forty cavities present in the FLASH linac in DESY. These electronics filter out a mode known to have a strong dependence on the beam´s position, and mix this down to a frequency suitable for digitisation. An analysis technique based on singular value decomposition (SVD) was developed to calculate the beam´s trajectory from the output of the electronics. The entire system has been integrated into the FLASH control system.

Keywords

accelerator cavities; accelerator control systems; electron beams; linear accelerators; nuclear electronics; particle beam diagnostics; DESY; FLASH control system; FLASH linac; SVD; beam position monitor; beam trajectory; cavity geometry; electron beam excitation; electronic filter; higher order mode excitation; singular value decomposition; superconducting accelerating cavity; Acceleration; Data mining; Electron beams; Filters; Frequency; Geometry; Monitoring; Particle beams; Particle measurements; Position measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

Particle Accelerator Conference, 2007. PAC. IEEE

Conference_Location

Albuquerque, NM

Print_ISBN

978-1-4244-0916-7

Type

conf

DOI

10.1109/PAC.2007.4440365

Filename

4440365