RuPAC2014 - List of Keywords (damping)

Paper	Title	Other Keywords	Page
TUY02	Status of Injection Complex VEPP-5	injection, electron, positron, closed-orbit	11
	A.A. Starostenko BINP SB RAS, Novosibirsk, Russia A.A. Starostenko NSU, Novosibirsk, Russia
	The status of Injection complex VEPP-5 commissioning are presented.
	Slides TUY02 [1.386 MB]

TUPSA18	Complex Shunt Impedance and Beam-RF Cavity Interaction	cavity, impedance, experiment, resonance	77
	V.G. Kurakin LPI, Moscow, Russia
	Two approaches usually are used to describe beam-cavity interaction in accelerator based applications. The first one is electro dynamical and uses Maxwell equations to derive appropriate equations, field modes expressions being necessary to calculate field amplitudes excited by moving charges in the cavity. The other one uses LC circuit to derive appropriate equations for voltage amplitude induced in cavity by accelerated bunches, thin accelerating gap to some extent being not fully correctly defined representation in such approach. In this paper, the expressions are derived that describe beam-RF cavity interactions in terms of so called complex shunt impedance, strict electro dynamical approach being used in calculations. It is shown that complex shunt impedance module coincides completely with usual shunt impedance definition that up to now is used widely to describe rf cavity efficiency. The physical sense of its phase is given in the paper as well. Both complex shunt impedance module and its phase can be calculated or measured experimentally.

WEPSB09	Comparision of Higher Order Modes Damping Techniques for Array of Single Cell Cavities	HOM, impedance, extraction, higher-order-mode	174
	Ya.V. Shashkov, N.P. Sobenin MEPhI, Moscow, Russia M. Zobov INFN/LNF, Frascati (Roma), Italy
	Funding: Research supported by RFBR grant 13-02-00562/14 and EU FP7 HiLumi LHC - Grant Agreement 284404" The LHC High Luminosity upgrade program considers an option of using additional cavities, operating at multiplies of the main RF system frequency of 400 MHz. Such harmonic cavities should provide a possibility to vary the length of colliding bunches. In order to supply the required harmonic voltage several single cell superconducting cavities are to be used. It is desirable to house more cavities in a single cryostat to reduce the number of transitions between "warm" and "cold" parts of the cryogenic system. In this paper we study electromagnetic characteristics of a chain of the single cell superconducting cavities coupled by drifts tubes. In order to reduce the influence of Higher order modes (HOM) excited in the structure on the beam stability and to minimize eventual power losses we analyze the HOM parameters and calculate the wake potential decay rates due to application of different HOM damping devices. In particular, the methods of HOM damping with rectangular waveguides connected to the drift tubes, the loads placed in the fluted and ridged drift tubes, as well as combinations of these methods are compared. Higher order modes, superconductivity, harmonic cavities

THPSC16	Analysis of High Order Modes Damping Techniques for 800 MHz Single Cell Superconducting Cavities	HOM, cavity, dipole, luminosity	353
	Ya.V. Shashkov, N.P. Sobenin MEPhI, Moscow, Russia M. Zobov INFN/LNF, Frascati (Roma), Italy
	Funding: Research supported by RFBR grant 13-02-00562/14 and EU FP7 HiLumi LHC - Grant Agreement 284404 The High Luminosity LHC upgrade program foresees a possibility of using the second harmonic cavities working at 800 MHz for the collider bunch length variation. Such harmonic cavities should provide an opportunity to vary the length of colliding bunches. In order to supply the required harmonic voltage several single cell superconducting cavities are to be used. Different cavity designs and several higher order mode (HOM) damping techniques are being studied in order to reduce the cavity HOM impact on the beam stability and to minimize parasitic power losses. In this paper we analyze and compare the HOM electromagnetic characteristics and respective wake potential decay rates for cavities with grooves, fluted and ridged beam pipes. The problem of Lorentz force detuning is also addressed.

THPSC17	Higher Order Modes Damping for 9-cell Structure with Modified Drift Tubes	HOM, cavity, quadrupole, dipole	356
	Ya.V. Shashkov, A.A. Mitrofanov, N.P. Sobenin MEPhI, Moscow, Russia V. Zvyagintsev TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Funding: Research supported by RFBR grant 13-02-00562/14 This paper is focused on HOM damping in 9-cell superconducting cavities. We are considering HOM propagation outside from the cavity ridged and fluted drift tubes. The analysis of the influence of the parameters of the drift tube on the HOM damping was conducted. The considered methods were analysed and compared.

THPSC20	Multipactor in Elliptical Cavities 800 MHz	cavity, electron, HOM, resonance	365
	M. Gusarova, I.I. Petrushina MEPhI, Moscow, Russia
	The studies of the multipacting discharge possibility in elliptic single-cell cavities at 800 MHz with three types of hifger order modes couplers were done. The ranges of the field gradients where the conditions for the occurrence of first order multipacting discharge in the equatorial region, as well as the HOM field levels were determined.

Paper

Title

Other Keywords

Page

TUY02

Status of Injection Complex VEPP-5

injection, electron, positron, closed-orbit

11

A.A. Starostenko
BINP SB RAS, Novosibirsk, Russia
A.A. Starostenko
NSU, Novosibirsk, Russia

The status of Injection complex VEPP-5 commissioning are presented.

Slides TUY02 [1.386 MB]

TUPSA18

Complex Shunt Impedance and Beam-RF Cavity Interaction

cavity, impedance, experiment, resonance

77

V.G. Kurakin
LPI, Moscow, Russia

Two approaches usually are used to describe beam-cavity interaction in accelerator based applications. The first one is electro dynamical and uses Maxwell equations to derive appropriate equations, field modes expressions being necessary to calculate field amplitudes excited by moving charges in the cavity. The other one uses LC circuit to derive appropriate equations for voltage amplitude induced in cavity by accelerated bunches, thin accelerating gap to some extent being not fully correctly defined representation in such approach. In this paper, the expressions are derived that describe beam-RF cavity interactions in terms of so called complex shunt impedance, strict electro dynamical approach being used in calculations. It is shown that complex shunt impedance module coincides completely with usual shunt impedance definition that up to now is used widely to describe rf cavity efficiency. The physical sense of its phase is given in the paper as well. Both complex shunt impedance module and its phase can be calculated or measured experimentally.

WEPSB09

Comparision of Higher Order Modes Damping Techniques for Array of Single Cell Cavities

HOM, impedance, extraction, higher-order-mode

174

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

Funding: Research supported by RFBR grant 13-02-00562/14 and EU FP7 HiLumi LHC - Grant Agreement 284404"
The LHC High Luminosity upgrade program considers an option of using additional cavities, operating at multiplies of the main RF system frequency of 400 MHz. Such harmonic cavities should provide a possibility to vary the length of colliding bunches. In order to supply the required harmonic voltage several single cell superconducting cavities are to be used. It is desirable to house more cavities in a single cryostat to reduce the number of transitions between "warm" and "cold" parts of the cryogenic system. In this paper we study electromagnetic characteristics of a chain of the single cell superconducting cavities coupled by drifts tubes. In order to reduce the influence of Higher order modes (HOM) excited in the structure on the beam stability and to minimize eventual power losses we analyze the HOM parameters and calculate the wake potential decay rates due to application of different HOM damping devices. In particular, the methods of HOM damping with rectangular waveguides connected to the drift tubes, the loads placed in the fluted and ridged drift tubes, as well as combinations of these methods are compared.
Higher order modes, superconductivity, harmonic cavities

THPSC16

Analysis of High Order Modes Damping Techniques for 800 MHz Single Cell Superconducting Cavities

HOM, cavity, dipole, luminosity

353

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

Funding: Research supported by RFBR grant 13-02-00562/14 and EU FP7 HiLumi LHC - Grant Agreement 284404
The High Luminosity LHC upgrade program foresees a possibility of using the second harmonic cavities working at 800 MHz for the collider bunch length variation. Such harmonic cavities should provide an opportunity to vary the length of colliding bunches. In order to supply the required harmonic voltage several single cell superconducting cavities are to be used. Different cavity designs and several higher order mode (HOM) damping techniques are being studied in order to reduce the cavity HOM impact on the beam stability and to minimize parasitic power losses. In this paper we analyze and compare the HOM electromagnetic characteristics and respective wake potential decay rates for cavities with grooves, fluted and ridged beam pipes. The problem of Lorentz force detuning is also addressed.

THPSC17

Higher Order Modes Damping for 9-cell Structure with Modified Drift Tubes

HOM, cavity, quadrupole, dipole

356

Ya.V. Shashkov, A.A. Mitrofanov, N.P. Sobenin
MEPhI, Moscow, Russia
V. Zvyagintsev
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Funding: Research supported by RFBR grant 13-02-00562/14
This paper is focused on HOM damping in 9-cell superconducting cavities. We are considering HOM propagation outside from the cavity ridged and fluted drift tubes. The analysis of the influence of the parameters of the drift tube on the HOM damping was conducted. The considered methods were analysed and compared.

THPSC20

Multipactor in Elliptical Cavities 800 MHz

cavity, electron, HOM, resonance

365

M. Gusarova, I.I. Petrushina
MEPhI, Moscow, Russia

The studies of the multipacting discharge possibility in elliptic single-cell cavities at 800 MHz with three types of hifger order modes couplers were done. The ranges of the field gradients where the conditions for the occurrence of first order multipacting discharge in the equatorial region, as well as the HOM field levels were determined.