ICAP2012 - List of Keywords (damping)

Paper	Title	Other Keywords	Page
WESCI3	Electromagnetic Characterization of Materials for the CLIC Damping Rings	simulation, impedance, electron, vacuum	198
	E. Koukovini-Platia, G. De Michele, G. Rumolo CERN, Geneva, Switzerland C. Zannini EPFL, Lausanne, Switzerland
	The performance of the Compact Linear Collider (CLIC) damping rings (DR) is likely to be limited by collective effects due to the unprecedented brilliance of the beams. Coating will be used in both electron (EDR) and positron damping rings (PDR) to suppress effects like electron cloud formation or ion instabilities. The impedance modeling of the chambers, necessary for the instabilities studies which will ensure safe operation under nominal conditions, must include the contribution from the coating materials applied for electron cloud mitigation and/or ultra-low vacuum pressure. This advocates for a correct characterization of this impedance in a high frequency range, which is still widely unexplored. The electrical conductivity of the materials in the frequency range of few GHz is determined with the waveguide method, based on a combination of experimental measurements of the complex transmission coefficient S21 and CST 3D electromagnetic (EM) simulations.
	Slides WESCI3 [2.488 MB]

THSDC3	Calculation of Longitudinal Instability Threshold Currents for Single Bunches	simulation, synchrotron, cavity, shielding	267
	P. Kuske HZB, Berlin, Germany
	Based on the publication by M. Venturini, et al.[1] a computer program has been written that solves the Vlasov-Fokker-Planck equation numerically on a two dimensional grid. In this code different types of longitudinal interactions and their combinations are implemented like the shielded CSR- as well as the purely resistive and inductive interactions of the electrons within the bunch. The details of the program will be presented in the paper. Calculations have been performed for the 1.7 GeV storage ring BESSY II and the 600 MeV ring MLS. The results are compared with measurements on both rings which were based on the observation of the onset of bursts of coherent synchrotron radiation. Fair agreement is found between theoretical and experimental observations. The theoretical results complement calculations performed by Bane, et al. for the shielded CSR-interaction [2]. The new results emphasize the resistive nature of the CSR-Interaction, especially in regions where shielding effects are small. [1] M. Venturini, et al., Phys. Rev. ST-SB, 8, 014202(2005) [2] K.L.F. Bane, et al., “Comparison of Simulation Codes for Microwave Instability in Bunched Beams“, IPAC 2010, Kyoto, Japan
	Slides THSDC3 [1.006 MB]

Paper

Title

Other Keywords

Page

WESCI3

Electromagnetic Characterization of Materials for the CLIC Damping Rings

simulation, impedance, electron, vacuum

198

E. Koukovini-Platia, G. De Michele, G. Rumolo
CERN, Geneva, Switzerland
C. Zannini
EPFL, Lausanne, Switzerland

The performance of the Compact Linear Collider (CLIC) damping rings (DR) is likely to be limited by collective effects due to the unprecedented brilliance of the beams. Coating will be used in both electron (EDR) and positron damping rings (PDR) to suppress effects like electron cloud formation or ion instabilities. The impedance modeling of the chambers, necessary for the instabilities studies which will ensure safe operation under nominal conditions, must include the contribution from the coating materials applied for electron cloud mitigation and/or ultra-low vacuum pressure. This advocates for a correct characterization of this impedance in a high frequency range, which is still widely unexplored. The electrical conductivity of the materials in the frequency range of few GHz is determined with the waveguide method, based on a combination of experimental measurements of the complex transmission coefficient S21 and CST 3D electromagnetic (EM) simulations.

Slides WESCI3 [2.488 MB]

THSDC3

Calculation of Longitudinal Instability Threshold Currents for Single Bunches

simulation, synchrotron, cavity, shielding

267

P. Kuske
HZB, Berlin, Germany

Based on the publication by M. Venturini, et al.[1] a computer program has been written that solves the Vlasov-Fokker-Planck equation numerically on a two dimensional grid. In this code different types of longitudinal interactions and their combinations are implemented like the shielded CSR- as well as the purely resistive and inductive interactions of the electrons within the bunch. The details of the program will be presented in the paper. Calculations have been performed for the 1.7 GeV storage ring BESSY II and the 600 MeV ring MLS. The results are compared with measurements on both rings which were based on the observation of the onset of bursts of coherent synchrotron radiation. Fair agreement is found between theoretical and experimental observations. The theoretical results complement calculations performed by Bane, et al. for the shielded CSR-interaction [2]. The new results emphasize the resistive nature of the CSR-Interaction, especially in regions where shielding effects are small.
[1] M. Venturini, et al., Phys. Rev. ST-SB, 8, 014202(2005)
[2] K.L.F. Bane, et al., “Comparison of Simulation Codes for Microwave Instability in Bunched Beams“, IPAC 2010, Kyoto, Japan

Slides THSDC3 [1.006 MB]