Title :
Evidence for a strongly coupled dipole mode with insufficient damping in TTF first accelerating module
Author :
Fartoukh, S. ; Jablonka, M. ; Joly, J.M. ; Lalot, M. ; Magne, C. ; Napoly, O. ; Bernard, M. ; Baboi, N. ; Schreiber, S. ; Simrock, S. ; Weise, H.
Author_Institution :
CEA, Saclay, France
Abstract :
A beam experiment has been conducted on the first accelerating module of the TESLA Test Facility (TTF) to investigate transverse higher order modes (HOM) in the superconducting cavities. By injecting the beam with a transverse offset and by modulating the intensity of the 216 MHz bunch train with a tunable frequency in the 0-108 MHz range, transverse HOMs can be excited resonantly. On a resonance the outgoing bunch orbits, measured with a broadband BPM, are transversely modulated at the same frequency. A dipole mode at about 2585 MHz, belonging to the third passband of the TESLA cavities, has been excited and observed in this way, with unexpected low damping in 2 out of the 8 cavities of the module
Keywords :
accelerator cavities; linear accelerators; proton accelerators; superconducting cavity resonators; 108 MHz; 216 MHz; 2585 MHz; TESLA Test Facility; TTF first accelerating module; bunch train; dipole mode; insufficient damping; outgoing bunch orbits; strongly coupled dipole mode; superconducting cavities; transverse higher order modes; transverse offset; tunable frequency; Extraterrestrial measurements; Frequency measurement; Intensity modulation; Life estimation; Optical modulation; Orbits; Particle beams; Passband; Resonance; Test facilities;
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.1999.795401
