IPAC2011 - List of Authors (Zhang, P.)

Paper

Title

Page

Study of Beam Diagnostics with Trapped Modes in Third Harmonic Superconducting Cavities at FLASH

2891

P. Zhang
DESY, Hamburg, Germany
P. Zhang
UMAN, Manchester, United Kingdom

Contribution selected for EPS-AG Prize d). Off-axis beams passing through an accelerating cavity excite dipole modes among other higher order modes (HOMs). These modes have linear dependence on the transverse beam offset from the cavity axis. Therefore they can be used to monitor the beam position within the cavity. The fifth dipole passband of the third harmonic superconducting cavities at FLASH has modes trapped within each cavity and do not propagate through the adjacent beam pipes, while most other cavity modes do. This could enable the beam position measurement in individual cavities. This paper investigates the possibility to use the fifth dipole band for beam alignment in the third harmonic cavity module. Simulations and measurements both with and without beam-excitations are presented. Various analysis methods are used and compared. A good correlation of HOM signals to the beam position is observed.

Slides THPPA00 [2.740 MB]

Paper	Title	Page
THPPA00	Study of Beam Diagnostics with Trapped Modes in Third Harmonic Superconducting Cavities at FLASH	2891
	P. Zhang DESY, Hamburg, Germany P. Zhang UMAN, Manchester, United Kingdom
	Contribution selected for EPS-AG Prize d). Off-axis beams passing through an accelerating cavity excite dipole modes among other higher order modes (HOMs). These modes have linear dependence on the transverse beam offset from the cavity axis. Therefore they can be used to monitor the beam position within the cavity. The fifth dipole passband of the third harmonic superconducting cavities at FLASH has modes trapped within each cavity and do not propagate through the adjacent beam pipes, while most other cavity modes do. This could enable the beam position measurement in individual cavities. This paper investigates the possibility to use the fifth dipole band for beam alignment in the third harmonic cavity module. Simulations and measurements both with and without beam-excitations are presented. Various analysis methods are used and compared. A good correlation of HOM signals to the beam position is observed.
	Slides THPPA00 [2.740 MB]