LINAC2016 - List of Keywords (damping)

Paper	Title	Other Keywords	Page
MOPLR006	Monopole HOMs Dumping in the LCLS-II 1.3 GHz Structure	HOM, cavity, linac, coupling	142
	A. Lunin, T.N. Khabiboulline, N. Solyak Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE Developing an upgrade of Linac Coherent Light Source (LCLS-II) is currently underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SRF) electron linac. High order modes (HOMs) excited in SRF structures by passing beam may deteriorate beam quality and affect beam stability. In this paper we report the simulation results of monopole High Order Modes (HOM) spectrum in the 1.3 GHz accelerating structure. Optimum parameters of the HOM feedthrough are suggested for minimizing RF losses on the HOM antenna tip and for preserving an efficiency of monopole HOMs damping simultaneously.
	Poster MOPLR006 [0.647 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR006
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP106006	Electro-Mechanical Modeling of the LCLS-II Superconducting Cavities	cavity, simulation, vacuum, linac	310
	O. Kononenko, C. Adolphsen, Z. Li, T.O. Raubenheimer, C.H. Rivetta SLAC, Menlo Park, California, USA
	Funding: Work supported by the Department of Energy, Office of Science, Office of Basic Energy Science, under Contract No. DEAC0276SF00515 The 4 GeV LCLS-II superconducting linac will contain 280, 1.3 GHz TESLA-style cavities operated CW at 16 MV/m. Because of the low beam current, the cavity bandwidth will be fairly small, about 32 Hz, which makes the field stability sensitive to detuning from external vibrations and He pressure fluctuations. Piezo-electric actuators will be used to compensate for the detuning, which historically has been difficult at frequencies above a few Hz due to excitation of cavity mechanical resonances. To understand this interaction better, we have been doing extensive modeling of the cavities including mapping out the mechanical modes and computing their coupling to pressure changes, Lorentz forces and piezo actuator motion. One goal is to reproduce the measured detuning response of the piezo actuators up to 1 kHz, which is sensitive to how the cavities are constrained within a cryomodule. In this paper, we summarize these results and their implications for suppressing higher frequency detuning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOP106006
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU2A04	High-Gradient RF Development and Applications	klystron, linac, collider, beam-loading	368
	W. Wuensch CERN, Geneva, Switzerland
	Significant progress has been made by the CLIC collaboration to understand the phenomena which limit gradient in normal-conducting accelerating structures and to increase achievable gradient in excess of 100 MV/m. Scientific and technological highlights from the CLIC high-gradient program are presented along with on-going developments and future plans. The talk will also give an overview of the range of applications that potentially benefit from high-frequency and high-gradient accelerating technology.
	Slides TU2A04 [14.317 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TU2A04
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPLR018	HOM Suppression Improvement for Mass Production of EXFEL Cavities at RI	cavity, HOM, linac, coupling	879
	A.A. Sulimov, J.H. Thie DESY, Hamburg, Germany M. Pekeler, D. Trompetter RI Research Instruments GmbH, Bergisch Gladbach, Germany
	During cold RF tests of the European XFEL (EXFEL) cavities at DESY it was observed that the damping of the second monopole mode (TM011) showed the largest variation, which was sometimes up to 2-3 times lower than the originally allowed limit. It was concluded that this TM011-damping degradation was caused by cavity geometry deviation within the specified mechanical tolerances. The particular influence of different mechanical parameters was analyzed and additional RF measurements were carried out to find the most critical geometry parameters. Stability of the equator welding and regularity of chemical treatment were investigated for different cavity cells. In spite of the high fabrication rate during EXFEL cavity mass production the TM011 suppression was improved to an acceptable level.
	Poster THPLR018 [0.378 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR018
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPLR006

Monopole HOMs Dumping in the LCLS-II 1.3 GHz Structure

HOM, cavity, linac, coupling

142

A. Lunin, T.N. Khabiboulline, N. Solyak
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Developing an upgrade of Linac Coherent Light Source (LCLS-II) is currently underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SRF) electron linac. High order modes (HOMs) excited in SRF structures by passing beam may deteriorate beam quality and affect beam stability. In this paper we report the simulation results of monopole High Order Modes (HOM) spectrum in the 1.3 GHz accelerating structure. Optimum parameters of the HOM feedthrough are suggested for minimizing RF losses on the HOM antenna tip and for preserving an efficiency of monopole HOMs damping simultaneously.

Poster MOPLR006 [0.647 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR006

Export •

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

MOP106006

Electro-Mechanical Modeling of the LCLS-II Superconducting Cavities

cavity, simulation, vacuum, linac

310

O. Kononenko, C. Adolphsen, Z. Li, T.O. Raubenheimer, C.H. Rivetta
SLAC, Menlo Park, California, USA

Funding: Work supported by the Department of Energy, Office of Science, Office of Basic Energy Science, under Contract No. DEAC0276SF00515
The 4 GeV LCLS-II superconducting linac will contain 280, 1.3 GHz TESLA-style cavities operated CW at 16 MV/m. Because of the low beam current, the cavity bandwidth will be fairly small, about 32 Hz, which makes the field stability sensitive to detuning from external vibrations and He pressure fluctuations. Piezo-electric actuators will be used to compensate for the detuning, which historically has been difficult at frequencies above a few Hz due to excitation of cavity mechanical resonances. To understand this interaction better, we have been doing extensive modeling of the cavities including mapping out the mechanical modes and computing their coupling to pressure changes, Lorentz forces and piezo actuator motion. One goal is to reproduce the measured detuning response of the piezo actuators up to 1 kHz, which is sensitive to how the cavities are constrained within a cryomodule. In this paper, we summarize these results and their implications for suppressing higher frequency detuning.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOP106006

Export •

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

TU2A04

High-Gradient RF Development and Applications

klystron, linac, collider, beam-loading

368

W. Wuensch
CERN, Geneva, Switzerland

Significant progress has been made by the CLIC collaboration to understand the phenomena which limit gradient in normal-conducting accelerating structures and to increase achievable gradient in excess of 100 MV/m. Scientific and technological highlights from the CLIC high-gradient program are presented along with on-going developments and future plans. The talk will also give an overview of the range of applications that potentially benefit from high-frequency and high-gradient accelerating technology.

Slides TU2A04 [14.317 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TU2A04

Export •

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

THPLR018

HOM Suppression Improvement for Mass Production of EXFEL Cavities at RI

cavity, HOM, linac, coupling

879

A.A. Sulimov, J.H. Thie
DESY, Hamburg, Germany
M. Pekeler, D. Trompetter
RI Research Instruments GmbH, Bergisch Gladbach, Germany

During cold RF tests of the European XFEL (EXFEL) cavities at DESY it was observed that the damping of the second monopole mode (TM011) showed the largest variation, which was sometimes up to 2-3 times lower than the originally allowed limit. It was concluded that this TM011-damping degradation was caused by cavity geometry deviation within the specified mechanical tolerances. The particular influence of different mechanical parameters was analyzed and additional RF measurements were carried out to find the most critical geometry parameters. Stability of the equator welding and regularity of chemical treatment were investigated for different cavity cells. In spite of the high fabrication rate during EXFEL cavity mass production the TM011 suppression was improved to an acceptable level.

Poster THPLR018 [0.378 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR018

Export •

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