Automated bead-positioning system for measuring impedances of RF cavity modes

Author

Goldberg, D.A. ; Rimmer, R.A.

Author_Institution

Lawrence Berkeley Lab., CA, USA

fYear

1993

fDate

17-20 May 1993

Firstpage

871

Abstract

We describe a fully automated bead puller system which uses stepping motors to position the bead, and an HP-8510 network analyzer to measure the resulting frequency shifts, both devices being under computer control. Longitudinal motion of the bead is used for measurement of cavity shunt impedance. In addition, azimuthal scans at fixed longitudinal position aid in determining the multipole character of higher-order modes. High sensitivity/accuracy is made possible by measuring phase shifts at the unperturbed resonant frequencies (rather than frequency shifts themselves), thereby permitting averaging factors of >500. With only modest increases in data acquisition time. Sample measurements will be presented

Keywords

cavity resonators; electric impedance measurement; particle accelerators; HP-8510 network analyzer; RF cavity modes; automated bead-positioning system; averaging factors; azimuthal scans; cavity shunt impedance; computer control; data acquisition time; fixed longitudinal position; frequency shifts; fully automated bead puller system; higher-order modes; impedance measurement; longitudinal motion; multipole character; phase shifts; sample measurements; stepping motors; unperturbed resonant frequencies; Computer networks; Control systems; Data acquisition; Frequency measurement; Impedance measurement; Motion measurement; Phase measurement; Position measurement; Radio frequency; Resonant frequency;

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.1993.308746

Filename

308746