IBIC2016 - List of Keywords (HOM)

Paper	Title	Other Keywords	Page
TUPG12	Design for the Diamond Longitudinal Bunch-by-Bunch Feedback Cavity	cavity, impedance, resonance, coupling	340
	A.F.D. Morgan, G. Rehm DLS, Oxfordshire, United Kingdom
	In 2017 it is planned to install some additional normal conducting cavities into the Diamond storage ring. In order to deal with the potential higher order modes in these we are designing a longitudinal bunch-by-bunch feedback system. This paper will focus on the design of the overloaded cavity kicker, adapted to the Diamond beam pipe cross section. The design has evolved in order to reduce the strong 3rd harmonic resonance seen on the introduction of the racetrack beam pipe. Through a combination of geometry optimisation and the addition of integrated taper transitions this harmonic has been greatly reduced while also minimising sharp resonances below 15GHz. The major features will be described, as well as the expected performance parameters.
	Poster TUPG12 [1.423 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG12
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WEPG03	HOM Characterization for Beam Diagnostics at the European XFEL Injector	cavity, dipole, monitoring, electron	616
	N. Baboi, T. Hellert, L. Shi, T. Wamsat DESY, Hamburg, Germany R.M. Jones, N.Y. Joshi, L. Shi UMAN, Manchester, United Kingdom N.Y. Joshi University of Manchester, Manchester, United Kingdom
	Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 31245. Higher Order Modes (HOM) excited by bunched elec-tron beams in accelerating cavities carry information about the beam position and phase. This principle is used at the FLASH facility, at DESY, for beam position monitoring in 1.3 and 3.9 GHz cavities. Dipole modes, which depend on the beam offset, are used. Similar monitors are now under design for the European XFEL. In addition to beam position, the beam phase with respect to the accelerating RF will be monitored using monopole modes from the first higher order monopole band. The HOM signals are available from two couplers installed on each cavity. Their monitoring will allow the on-line tracking of the phase stability over time, and we anticipate that it will improve the stability of the facility. As part of the monitor designing, the HOM spectra in the cavities of the 1.3 and 3.9 GHz cryo-modules installed in the European XFEL injector have been measured. This paper will present their dependence on the beam position. The variation in the modal distribution from cavity to cavity will be discussed. Based on the results, initial phase measurements based on a fast oscilloscope have been made.
	Poster WEPG03 [3.281 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TUPG12

Design for the Diamond Longitudinal Bunch-by-Bunch Feedback Cavity

cavity, impedance, resonance, coupling

340

A.F.D. Morgan, G. Rehm
DLS, Oxfordshire, United Kingdom

In 2017 it is planned to install some additional normal conducting cavities into the Diamond storage ring. In order to deal with the potential higher order modes in these we are designing a longitudinal bunch-by-bunch feedback system. This paper will focus on the design of the overloaded cavity kicker, adapted to the Diamond beam pipe cross section. The design has evolved in order to reduce the strong 3rd harmonic resonance seen on the introduction of the racetrack beam pipe. Through a combination of geometry optimisation and the addition of integrated taper transitions this harmonic has been greatly reduced while also minimising sharp resonances below 15GHz. The major features will be described, as well as the expected performance parameters.

Poster TUPG12 [1.423 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG12

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPG03

HOM Characterization for Beam Diagnostics at the European XFEL Injector

cavity, dipole, monitoring, electron

616

N. Baboi, T. Hellert, L. Shi, T. Wamsat
DESY, Hamburg, Germany
R.M. Jones, N.Y. Joshi, L. Shi
UMAN, Manchester, United Kingdom
N.Y. Joshi
University of Manchester, Manchester, United Kingdom

Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 31245.
Higher Order Modes (HOM) excited by bunched elec-tron beams in accelerating cavities carry information about the beam position and phase. This principle is used at the FLASH facility, at DESY, for beam position monitoring in 1.3 and 3.9 GHz cavities. Dipole modes, which depend on the beam offset, are used. Similar monitors are now under design for the European XFEL. In addition to beam position, the beam phase with respect to the accelerating RF will be monitored using monopole modes from the first higher order monopole band. The HOM signals are available from two couplers installed on each cavity. Their monitoring will allow the on-line tracking of the phase stability over time, and we anticipate that it will improve the stability of the facility. As part of the monitor designing, the HOM spectra in the cavities of the 1.3 and 3.9 GHz cryo-modules installed in the European XFEL injector have been measured. This paper will present their dependence on the beam position. The variation in the modal distribution from cavity to cavity will be discussed. Based on the results, initial phase measurements based on a fast oscilloscope have been made.

Poster WEPG03 [3.281 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)