IPAC2014 - List of Authors (Sommer, M.)

Paper	Title	Page
WEPRI009	Parameter Studies and Geometry Optimization on Superconducting Multicell RF Cavity Resonators	2496
	B.D. Isbarn, B. Riemann, M. Sommer, T. Weis DELTA, Dortmund, Germany
	Funding: Work partly supported by the BMBF under contract No. 05K13PEB Modern accelerator concepts for high intensity electron beams often require superconducting multicell RF-cavity-resonators in circular accelerators (e.g. storage rings). Caused by strong beam-cavity interaction and due to high quality factors of superconducting RF-structures special care of lower order (LOM) and higher order (HOM) modes must be taken. Various numerical studies were performed to numerically calculate the dependence of different figures of merit (e.g. external quality factors Qext) with respect to the geometry parameters and cell number of the RF-structure, focused on the propagation and damping of low and higher order modes. To ease the numerical effort an optimization routine has been developed which automatically optimizes the geometry based on goal functions. In this context it turned out that cell geometries defined by spline functions have advantages compared to the standard elliptical parametrization regularly used. The number of free parameters is substantially reduced which facilitates the search for optimum solutions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI009
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THPME104	Investigation of Beam Instabilities at DELTA using Bunch-by-bunch Feedback Systems	3486
	M. Höner, S. Hilbrich, H. Huck, M. Huck, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, M. Sommer, P. Ungelenk DELTA, Dortmund, Germany
	Funding: Work supported by the BMBF (05K13PEC). At the 1.5-GeV electron storage ring DELTA operated by the TU Dortmund University as a synchrotron radiation user facility, bunch-by-bunch feedback systems are in use for electron beam diagnostics and for the suppression of multibunch instabilities. An automatic readout of bunch position data allows a real-time modal analysis during machine operation. An excitation of particular multibunch modes enables the determination of growth and damping times for all modes independently. Further investigations of beam stability and natural damping times of all modes even below the instability threshold have been performed. In addition, first bunch-by-bunch data taken from the booster synchrotron are shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME104
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Parameter Studies and Geometry Optimization on Superconducting Multicell RF Cavity Resonators

2496

B.D. Isbarn, B. Riemann, M. Sommer, T. Weis
DELTA, Dortmund, Germany

Funding: Work partly supported by the BMBF under contract No. 05K13PEB
Modern accelerator concepts for high intensity electron beams often require superconducting multicell RF-cavity-resonators in circular accelerators (e.g. storage rings). Caused by strong beam-cavity interaction and due to high quality factors of superconducting RF-structures special care of lower order (LOM) and higher order (HOM) modes must be taken. Various numerical studies were performed to numerically calculate the dependence of different figures of merit (e.g. external quality factors Qext) with respect to the geometry parameters and cell number of the RF-structure, focused on the propagation and damping of low and higher order modes. To ease the numerical effort an optimization routine has been developed which automatically optimizes the geometry based on goal functions. In this context it turned out that cell geometries defined by spline functions have advantages compared to the standard elliptical parametrization regularly used. The number of free parameters is substantially reduced which facilitates the search for optimum solutions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI009

Export •

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

THPME104

Investigation of Beam Instabilities at DELTA using Bunch-by-bunch Feedback Systems

3486

M. Höner, S. Hilbrich, H. Huck, M. Huck, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, M. Sommer, P. Ungelenk
DELTA, Dortmund, Germany

Funding: Work supported by the BMBF (05K13PEC).
At the 1.5-GeV electron storage ring DELTA operated by the TU Dortmund University as a synchrotron radiation user facility, bunch-by-bunch feedback systems are in use for electron beam diagnostics and for the suppression of multibunch instabilities. An automatic readout of bunch position data allows a real-time modal analysis during machine operation. An excitation of particular multibunch modes enables the determination of growth and damping times for all modes independently. Further investigations of beam stability and natural damping times of all modes even below the instability threshold have been performed. In addition, first bunch-by-bunch data taken from the booster synchrotron are shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME104

Export •

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