LINAC2014 - List of Authors (Kuramoto, A.)

Paper	Title	Page
MOPP133	Measurements of Cavity Misalignment by Beam Induced HOM Excited in 9-cell Superconducting Cavities	370
	A. Kuramoto Sokendai, Ibaraki, Japan N. Baboi DESY, Hamburg, Germany H. Hayano KEK, Ibaraki, Japan
	Detection of cavity misalignment in the ILC superconducting cavities inside of the cryomodules can be done by using beam induced Higher Order Modes (HOM). It is beneficial to identify possible source of emittance growth by cavity misalignment. Beam pipe modes which are localized in both ends of the cavity and TE111 1/9 pi mode which is localized in the center of the cavity are focused in this research. Deviations of these electrical centers from beam trajectory reference indicate cavity misalignment and bending. We measured beam-induced HOM in STF cavities of the STF accelerator at KEK in 2012 – 2013 and TESLA cavities of FLASH at DESY in 2013. We could identify beam pipe modes and TE111 1/9 pi mode in STF cavities and TESLA cavities at around 2.1 GHz and 1.6 GHz, both of which were very small signals. The electrical center of these beam pipe mode are studied by stretched wire method, beads perturbation method and simulations by CST MICROWAVE STUDIO 2012 and HFSS 12. In this paper, the results of these measurements and simulations are summarized.

Paper

Title

Page

Measurements of Cavity Misalignment by Beam Induced HOM Excited in 9-cell Superconducting Cavities

370

A. Kuramoto
Sokendai, Ibaraki, Japan
N. Baboi
DESY, Hamburg, Germany
H. Hayano
KEK, Ibaraki, Japan

Detection of cavity misalignment in the ILC superconducting cavities inside of the cryomodules can be done by using beam induced Higher Order Modes (HOM). It is beneficial to identify possible source of emittance growth by cavity misalignment. Beam pipe modes which are localized in both ends of the cavity and TE111 1/9 pi mode which is localized in the center of the cavity are focused in this research. Deviations of these electrical centers from beam trajectory reference indicate cavity misalignment and bending. We measured beam-induced HOM in STF cavities of the STF accelerator at KEK in 2012 – 2013 and TESLA cavities of FLASH at DESY in 2013. We could identify beam pipe modes and TE111 1/9 pi mode in STF cavities and TESLA cavities at around 2.1 GHz and 1.6 GHz, both of which were very small signals. The electrical center of these beam pipe mode are studied by stretched wire method, beads perturbation method and simulations by CST MICROWAVE STUDIO 2012 and HFSS 12. In this paper, the results of these measurements and simulations are summarized.