IPAC2015 - List of Authors (Shashkov, Ya.V.)

Paper	Title	Page
WEPMN046	Compassion of Higher Order Modes Damping Techniques for Superconducting 9-Cell Structure	3030
	Ya.V. Shashkov, A.A. Mitrofanov, N.P. Sobenin MEPhI, Moscow, Russia V. Zvyagintsev TRIUMF, Vancouver, Canada
	Funding: Work supported by Ministry of Education and Science grant 3.245.2014/r Modern types of accelerators, such as Energy recovery linacs, require low values of higher order modes (HOM) Qext. In accelerators with high current HOM could lead to high losses for the modes excitation, beam instability and beam break up. HOM couplers and waveguides are often used in such structures for HOM damping. Unfortunately they could lead to a violation of the axial symmetry of the accelerating field and negatively affect the beam emittance. Also these devices are subject for multipactor discharge and could be difficult in maintaining and fabrication. In this paper we examine several ways of HOM damping with ridged, fluted and corrugated drift tubes which are devoid of the above-mentioned drawbacks. The influence of the parameters of the drift tube on the HOM damping and on the parameters of the fundamental wave were analyzed. Higher order modes, ERL, SRF
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN046
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WEPMN047	Suppression of Higher Order Modes in an Array of Cavities Using Waveguides	3033
	Ya.V. Shashkov, N.P. Sobenin MEPhI, Moscow, Russia M. Zobov INFN/LNF, Frascati (Roma), Italy
	Funding: Work is supported by Ministry of Education and Science grant 3.245.2014/r и and by the EU FP7 HiLumi LHC - Grant Agreement 284404 In the frameworks of the High Luminosity LHC upgrade program an application of additional harmonic cavities operating at multiplies of the main RF system frequency of 400 MHz is currently under discussion. A structure consisting of two 800 MHz single cell superconducting cavities with grooved beam pipes coupled by drift tubes has been suggested for implementation. However, it is desirable to increase the number of single cells installed in one cryomodule in order to decrease the number of transitions between “warm” and “cold” parts of the collider vacuum chamber. Unfortunately it can lead to the appearance of higher order modes (HOM) trapped between the cavities. In order to solve this problem the methods of HOM damping with rectangular waveguides connected to the drift tubes were investigated and compared. In this paper we describe the results obtained for arrays of 2, 4 and 8 cavities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN047
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Compassion of Higher Order Modes Damping Techniques for Superconducting 9-Cell Structure

3030

Ya.V. Shashkov, A.A. Mitrofanov, N.P. Sobenin
MEPhI, Moscow, Russia
V. Zvyagintsev
TRIUMF, Vancouver, Canada

Funding: Work supported by Ministry of Education and Science grant 3.245.2014/r
Modern types of accelerators, such as Energy recovery linacs, require low values of higher order modes (HOM) Qext. In accelerators with high current HOM could lead to high losses for the modes excitation, beam instability and beam break up. HOM couplers and waveguides are often used in such structures for HOM damping. Unfortunately they could lead to a violation of the axial symmetry of the accelerating field and negatively affect the beam emittance. Also these devices are subject for multipactor discharge and could be difficult in maintaining and fabrication. In this paper we examine several ways of HOM damping with ridged, fluted and corrugated drift tubes which are devoid of the above-mentioned drawbacks. The influence of the parameters of the drift tube on the HOM damping and on the parameters of the fundamental wave were analyzed.
Higher order modes, ERL, SRF

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN046

Export •

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

WEPMN047

Suppression of Higher Order Modes in an Array of Cavities Using Waveguides

3033

Ya.V. Shashkov, N.P. Sobenin
MEPhI, Moscow, Russia
M. Zobov
INFN/LNF, Frascati (Roma), Italy

Funding: Work is supported by Ministry of Education and Science grant 3.245.2014/r и and by the EU FP7 HiLumi LHC - Grant Agreement 284404
In the frameworks of the High Luminosity LHC upgrade program an application of additional harmonic cavities operating at multiplies of the main RF system frequency of 400 MHz is currently under discussion. A structure consisting of two 800 MHz single cell superconducting cavities with grooved beam pipes coupled by drift tubes has been suggested for implementation. However, it is desirable to increase the number of single cells installed in one cryomodule in order to decrease the number of transitions between “warm” and “cold” parts of the collider vacuum chamber. Unfortunately it can lead to the appearance of higher order modes (HOM) trapped between the cavities. In order to solve this problem the methods of HOM damping with rectangular waveguides connected to the drift tubes were investigated and compared. In this paper we describe the results obtained for arrays of 2, 4 and 8 cavities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN047

Export •

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