Title :
RF modes in the PEP-II shielded vertex bellows
Author :
Novokhatski, A. ; Weathersby, S.
Author_Institution :
Stanford Linear Accelerator Center, CA, USA
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;
Conference_Titel :
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the
Print_ISBN :
0-7803-7738-9
DOI :
10.1109/PAC.2003.1289787
