Title :
Damping spurious harmonic resonances in the APS storage ring beam chamber
Author :
Kang, Y. ; Decker, G. ; Song, J.
Author_Institution :
Argonne Nat., Lab., IL, USA
Abstract :
The APS storage ring beam chamber has been storing the beam up to 100 mA successfully. However, in some beam chambers, spurious signals corrupted the BPM outputs. The cause of the unwanted signals was investigated, and it was found that transverse electric (TE) longitudinal harmonic resonances of the beam chamber were responsible. The beam chambers have small height in the area between the oval beam chamber and the antechamber. The structure behaves like a ridge waveguide so that the cut-off frequency of the waveguide mode becomes lower. The pass-band then includes the frequency around 350 MHz that is important to the beam position monitors (BPMs). The spurious harmonic resonances are damped with two types of dampers to restore the useful signals of the BPMs; coaxial loop dampers and lossy ceramic slab loading are used
Keywords :
beam handling equipment; electron accelerators; particle beam diagnostics; particle beam stability; storage rings; 350 MHz; APS storage ring beam chamber; antechamber; beam position monitors; coaxial loop dampers; cut-off frequency; lossy ceramic slab loading; oval beam chamber; ridge waveguide; spurious harmonic resonances damping; spurious signals; transverse electric longitudinal harmonic resonances; unwanted signals; waveguide mode; Cameras; Ceramics; Coaxial components; Damping; Displays; Frequency; Large Hadron Collider; Resonance; Storage rings; Vacuum arcs;
Conference_Titel :
Particle Accelerator Conference, 1999. Proceedings of the 1999
Conference_Location :
New York, NY
Print_ISBN :
0-7803-5573-3
DOI :
10.1109/PAC.1999.792190
