Title :
The interaction of a beam with a beam line higher-order mode absorber
Author :
Hartung, W. ; Akai, K. ; DeFord, J. ; Hays, T. ; Kirchgessner, J. ; Metzger, D. ; Moffat, D. ; Padamsee, H. ; Rubin, D. ; Tigner, M. ; Tribenis, A. ; Veshcherevich, V.
Author_Institution :
Lab. of Nucl. Studies, Cornell Univ., Ithaca, NY, USA
Abstract :
Plans for CESR-B, the proposed upgrade of the CESR e+e - storage ring to a B-factory, call for beam currents of ~1 A. Studies indicate that the beams will be unstable unless the higher-order modes (HOMs) in the superconducting cavities are strongly damped; Q<100 is required for the dangerous modes. The cavity is designed to enable all HOMs to propagate into the beam pipe, where 8 layer of microwave-absorbing ferrite is to provide the damping. The load geometry is shown. RF measurements with a full-size mock-up of the cavity and loads made of two types of ferrite, TT2-lll-series and Ferrite-50, indicate that this scheme provides the required damping. The HOM loads can also interact directly with the beam. Preliminary predictions for the effect of loads made of TT2-111V ferrite on beam stability in CESR-B are given
Keywords :
beam handling equipment; damping; electron accelerators; particle beam diagnostics; storage rings; B-factory; CESR-B; Ferrite-50; TT2-111V ferrite; beam currents; beam line higher-order mode absorber; beam pipe; beam stability; damping; e+e- storage ring; higher-order modes; microwave-absorbing ferrite; superconducting cavities; Conducting materials; Conductivity; Damping; Ferrites; Frequency; Geometry; Impedance; Optical coupling; Particle beams; Transmission line measurements;
Conference_Titel :
Particle Accelerator Conference, 1993., Proceedings of the 1993
Conference_Location :
Washington, DC
Print_ISBN :
0-7803-1203-1
DOI :
10.1109/PAC.1993.309680
