RF modes in the PEP-II shielded vertex bellows

Author

Novokhatski, A. ; Weathersby, S.

Author_Institution

Stanford Linear Accelerator Center, CA, USA

Volume

5

fYear

2003

fDate

12-16 May 2003

Firstpage

2981

Abstract

Experimental and simulation study of RF modes were carried out for the complicated geometry of the shielded vertex bellows near the IP region of the PEP-II B-factory. A beam position monitor button electrode located 50 cm from the bellows provides a signal for spectrum measurement. Calculations indicate monopole, dipole and quadrupole modes can exist in the bellows structure near the experimentally observed frequency region of 5 GHz. The observed modes are correlated to the bellows heating. The beam-generated fields are scattered by the masks, taper and axial offsets and heat the bellows by coupling through the RF shield fingers.

Keywords

accelerator RF systems; beam handling techniques; electron accelerators; particle beam diagnostics; storage rings; 5 GHz; 50 cm; PEP-II B-factory; PEP-II shielded vertex bellows; RF modes; RF shield fingers; beam position monitor button electrode; beam-generated fields; bellows heating; dipole mode; frequency region; monopole mode; quadrupole mode; spectrum measurement; Bellows; Electrodes; Geometry; Heating; Monitoring; Optical coupling; Position measurement; Radio frequency; Scattering; Solid modeling;

fLanguage

English

Publisher

ieee

Conference_Titel

Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the

ISSN

1063-3928

Print_ISBN

0-7803-7738-9

Type

conf

DOI

10.1109/PAC.2003.1289787

Filename

1289787