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| DYN01 |
Numerical Modeling of E-Cloud Driven Instability and its Mitigation using a Simulated Feedback System in the CERN SPS
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- J. Vay, J. Byrd, M. Furman, R. Secondo, M. Venturini
LBNL
- J. Fox, C. Rivetta
SLAC National Accelerator Laboratory
- W. Hofle
CERN
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Funding: Supported by the US-DOE under Contract DE-AC02-05CH11231, the US-LHC Accelerator Research Program (LARP) and the SciDAC program ComPASS. Used resources of NERSC and the Lawrencium cluster at LBNL.
Electron clouds impose limitations on current accelerators that may be more severe for future machines, unless adequate measures of mitigation are taken. Recently, it has been proposed to use feedback systems operating at high frequency (in the GHz range) to damp single-bunch transverse coherent oscillations that may otherwise be amplified during the interaction of the beam with ambient electron clouds. We have used the simulation package WARP-POSINST to study the growth rate and frequency patterns in space-time of the electron cloud driven transverse instability in the CERN SPS accelerator with, or without, feedback models (with various levels of idealization) for damping the instability. We will present our latest simulation results, contrast them with actual measurements and discuss the implications for the design of the actual feedback system. More simulations results are presented by Raffaello Secondo using a Finite Impulse Response (FIR) as processing channel in a more realistic, albeit yet highly simplified, model of feedback control system.
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Slides
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| DYN02 |
Simulated Performance of an FIR-Based Feedback System to Control the Electron Cloud Single-Bunch Transverse Instabilities in the CERN SPS
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56 |
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- R. Secondo, J. Byrd, M. Furman, M. Venturini, J. Vay
LBNL
- J. Fox, C. Rivetta
SLAC National Accelerator Laboratory
- W. Hofle
CERN
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The performance of High Energy proton machines like the SPS at CERN is affected by transverse single-bunch instabilities due to the Electron Cloud effect. In a first step to model a Feedback control system to stabilize the bunch dynamics, we use a Finite Impulse Response filter to represent the processing channel. The effect of this simplified processing channel in the bunch dynamics is analyzed using the simulation package WARP-POSINST. We report on simulation results, discuss the basic features of the feedback model and present our plans for further development of the numerical models used in the simulations.
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Slides
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| PST00 |
E-Cloud Effects on Single-Bunch Dynamics in the Proposed PS2
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79 |
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- M. Venturini, M. Furman, J. Vay
LBNL
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One of the options considered for a future aupgrade of the LHC injection complex entails the replacement of PS with PS2, a larger circumference and higher-energy synchrotron. Electron cloud has been identified as a potential limitation to the machine performance. We review studies of e-cloud build-up and present recent results of simulations of short-term e-cloud effects on the single-bunch dynamics in the smooth-lattice, quasi-static approximation, as implemented in the code Warp.
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| PST10 |
Using Coherent Tune Shifts to Evaluate Electron Cloud Effects on Beam Dynamics at CesrTA
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130 |
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- D. Kreinick, J. Crittenden, G. Dugan, Z. Leong, M. Palmer
Cornell University - CLASSE
- R. Holtzapple, M. Randazzo
California Polytechnic State University
- M. Furman, M. Venturini
LBNL
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One technique used at CesrTA for studying the effects of electron clouds on beam dynamics is to measure electron and positron bunch tunes under a wide variety of beam energies, bunch charge, and bunch train configurations. Comparing the observed tunes with the predictions of various simulation programs allows the evaluation of important parameters in the cloud formation models. These simulations will be used to predict the behavior of the electron cloud in damping rings for future linear colliders.
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