Title :
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
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;
Conference_Titel :
Particle Accelerator Conference, 1993., Proceedings of the 1993
Conference_Location :
Washington, DC
Print_ISBN :
0-7803-1203-1
DOI :
10.1109/PAC.1993.308746
