SRF2013 - List of Authors (Kuramoto, A.)

Paper	Title	Page
THP094	Beam Induced HOM Analysis in STF	1144
	A. Kuramoto Sokendai, Ibaraki, Japan H. Hayano KEK, Ibaraki, Japan
	Requirements of superconducting cavity (SC) alignment for ILC are less than 300 μm offset and 300 μrad tilt with respect to cryomodule. It is necessary to measure their offset and tilt inside of cryomodule. Cavity offset has been already measured by using beam induced HOM at FLASH in DESY. Cavity deformation during assembly and by cooling contraction has not been examined yet. To detect their tilt and bending, we measured HOM signals with beam trajectory sweep. Our interesting modes are pi over nine mode in the first dipole passband (TE111-1) which is trapped mode has maximum radial electric field in the middle cell and beam pipe modes localized in the both end-group of the SC. These modes tell us electrical center of middle cell and electrical centers at both beam pipe. We can know cavity tilt and bending from combinations of them. The experiment to find these HOM was performed at STF accelerator. Electron beam extracted from the RF Gun was accelerated to 40 MeV by the SC cavities. We could find TE111-1 and beam pipe modes. These HOM signals were correlated with beam orbit, accelerating field gradient. The detailed data analysis is introduced in this paper.

Paper

Title

Page

Beam Induced HOM Analysis in STF

1144

A. Kuramoto
Sokendai, Ibaraki, Japan
H. Hayano
KEK, Ibaraki, Japan

Requirements of superconducting cavity (SC) alignment for ILC are less than 300 μm offset and 300 μrad tilt with respect to cryomodule. It is necessary to measure their offset and tilt inside of cryomodule. Cavity offset has been already measured by using beam induced HOM at FLASH in DESY. Cavity deformation during assembly and by cooling contraction has not been examined yet. To detect their tilt and bending, we measured HOM signals with beam trajectory sweep. Our interesting modes are pi over nine mode in the first dipole passband (TE111-1) which is trapped mode has maximum radial electric field in the middle cell and beam pipe modes localized in the both end-group of the SC. These modes tell us electrical center of middle cell and electrical centers at both beam pipe. We can know cavity tilt and bending from combinations of them. The experiment to find these HOM was performed at STF accelerator. Electron beam extracted from the RF Gun was accelerated to 40 MeV by the SC cavities. We could find TE111-1 and beam pipe modes. These HOM signals were correlated with beam orbit, accelerating field gradient. The detailed data analysis is introduced in this paper.