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in creator/contributor: "Rumolo, G."  
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Modeling Incoherent Electron Cloud Effects

Description: Incoherent electron effects could seriously limit the beam lifetime in proton or ion storage rings, such as LHC, SPS, or RHIC, or blow up the vertical emittance of positron beams, e.g., at the B factories or in linear-collider damping rings. Different approaches to modeling these effects each have their own merits and drawbacks. We describe several simulation codes which simplify the descriptions of the beam-electron interaction and of the accelerator structure in various different ways, and pr… more
Date: June 18, 2007
Creator: Vay, Jean-Luc; Benedetto, E.; Fischer, W.; Franchetti, G.; Ohmi, K.; Schulte, D. et al.
Partner: UNT Libraries Government Documents Department
open access

Modeling Incoherent Electron Cloud Effects

Description: Incoherent electron effects could seriously limit the beam lifetime in proton or ion storage rings, such as LHC, SPS, or RHIC, or blow up the vertical emittance of positron beams, e.g., at the B factories or in linear-collider damping rings. Different approaches to modeling these effects each have their own merits and drawbacks. We describe several simulation codes which simplify the descriptions of the beam-electron interaction and of the accelerator structure in various different ways, and pr… more
Date: January 24, 2008
Creator: Fischer, W.; Benedetto, E.; Rumolo, G.; Schulte, D.; Tomas, R.; Zimmermann, Frank et al.
Partner: UNT Libraries Government Documents Department
open access

Electron-cloud Build-up Simulations in the Proposed PS2: Status Report

Description: A replacement for the PS storage ring is being considered, in the context of the future LHC accelerator complex upgrade, that would likely place the new machine (the PS2) in a regime where the electron-cloud (EC) effect might be significant. We report here our current estimate of the EC density ne in the bending magnets and the field-free regions at injection and extraction beam energy, for both proposed bunch spacings, tb = 25 and 50 ns. The primary model parameters exercised are the peak seco… more
Date: May 5, 2010
Creator: Furman, M. A.; De Maria, R.; Papaphilippou, Y. & Rumolo, G.
Partner: UNT Libraries Government Documents Department
open access

Conceptual Design of the CLIC Damping Rings

Description: In order to achieve high luminosity in CLIC, ultra-low emittance bunches have to be generated in both electron and positron damping rings. To achieve this goal, big energy loss per turn in the wigglers has to be compensated by the RF system. This results in very strong beam loading transients affecting the longtudinal bunch position and bunch length. In this paper, the conceptual design of the RF system for the CLIC damping ring (DR) is presented. Baseline for the CLIC conceptual design report … more
Date: October 10, 2013
Creator: Boland, M. J.; Korostelev, M.; Palmer, M. A.; Koukovini, E.; Antoniou, F.; Chiggiato, P. et al.
Partner: UNT Libraries Government Documents Department
open access

Electron Cloud at Low Emittance in CesrTA

Description: The Cornell Electron Storage Ring (CESR) has been reconfigured as a test accelerator (CesrTA) for a program of electron cloud (EC) research at ultra low emittance. The instrumentation in the ring has been upgraded with local diagnostics for measurement of cloud density and with improved beam diagnostics for the characterization of both the low emittance performance and the beam dynamics of high intensity bunch trains interacting with the cloud. A range of EC mitigation methods have been deploye… more
Date: May 23, 2010
Creator: Alexander, J. P.; Billing, M. G.; Calvey, J.; Crittenden, J. A.; Dugan, G.; Eggert, N. et al.
Partner: UNT Libraries Government Documents Department
open access

SPS Ecloud Instabilities - Analysis of Machine Studies and Implications for Ecloud Feedback

Description: The SPS at high intensities exhibits transverse single bunch instabilities with signatures consistent with an Ecloud driven instability. We present recent MD data from the SPS, details of the instrument technique and spectral analysis methods which help reveal complex vertical motion that develops within a subset of the injected bunch trains. The beam motion is detected via wideband exponential taper striplines and delta-sigma hybrids. The raw sum and difference data is sampled at 50 GHz with 1… more
Date: May 25, 2011
Creator: Fox, J.; Bullitt, A.; Mastorides, T.; Ndabashimiye, G.; Rivetta, C. H.; Turgut, O. et al.
Partner: UNT Libraries Government Documents Department
open access

Analysis of the transverse SPS beam coupling impedance with short and long bunches

Description: The upgrade of the CERN Large Hadron Collider (LHC) would require a four- to five-fold increase of the single bunch intensity presently obtained in the Super Proton Synchrotron (SPS). Operating at such high single bunch intensities requires a detailed knowledge of the sources of SPS beam coupling impedance, so that longitudinal and transverse impedance reduction campaigns can be planned and performed effectively if needed. In this paper, the transverse impedance of the SPS is studied by injecti… more
Date: May 4, 2009
Creator: Salvant, B.; Calaga, R.; De Maria, R.; Arduini, G.; Burkhardt, H.; Damerau, H. et al.
Partner: UNT Libraries Government Documents Department
open access

Feedback techniques and SPS Ecloud instabilities - design estimates

Description: The SPS at high intensities exhibits transverse single-bunch instabilities with signatures consistent with an Ecloud driven instability. While the SPS has a coupled-bunch transverse feedback system, control of Ecloud driven motion requires a much wider control bandwidth capable of sensing and controlling motion within each bunched beam. This paper draws beam dynamics data from the measurements and simulations of this SPS instability, and estimates system requirements for a feedback system with … more
Date: May 4, 2009
Creator: Fox, J. D.; Mastorides, T.; Ndabashimiye, G.; Rivetta, C.; Van Winkle, D.; Byrd, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Simulation of a Feedback System for the Attenuation of e-Cloud Driven Instability

Description: 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 and the code Headtail to study the growth r… more
Date: May 4, 2009
Creator: Vay, J. L.; Furman, M. A.; Fox, J.; Rivetta, C.; De Maria, R. & Rumolo, G.
Partner: UNT Libraries Government Documents Department
open access

Performance of exponential coupler in the SPS with LHC type beam for transverse broadband instability analysis

Description: We present the performance and limitations of the SPS exponential coupler [1] for transverse instability measurements with LHC type beam. Data were acquired in 2008 in the SPS in the time domain with a bandwidth of up to 2.5 GHz. The data were filtered to extract the time evolution of transverse oscillations within the less than 5 ns long LHC type bunches. We describe the data filtering techniques and show the limitations of the pick-up due to propagating modes.
Date: May 25, 2009
Creator: De Maria, R.; Fox, J. D.; Hofle, W.; Kotzian, G.; Rumolo, G.; Salvant, B. et al.
Partner: UNT Libraries Government Documents Department
open access

Accelerator physics code web repository

Description: No Description Available.
Date: June 1, 2006
Creator: Zimmermann, F.; Basset, R.; Bellodi, G.; Benedetto, E.; Dorda, U.; Giovannozzi, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Feedback Techniques and Ecloud Instabilites - Design Estimates

Description: The SPS at high intensities exhibits transverse single-bunch instabilities with signatures consistent with an Ecloud driven instability. While the SPS has a coupled-bunch transverse feedback system, control of Ecloud-driven motion requires a much wider control bandwidth capable of sensing and controlling motion within each bunched beam. This paper draws beam dynamics data from the measurements and simulations of this SPS instability, and estimates system requirements for a feedback system with … more
Date: May 18, 2009
Creator: Fox, J. D.; Mastorides, T.; Ndabashimiye, G.; Rivetta, C.; Winkle, D. Van; Byrd, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Transverse impedance localization using intensity dependent optics

Description: Measurements of transverse impedance in the SPS to track the evolution over the last few years show discrepancies compared to the analytical estimates of the major contributors. Recent measurements to localize the major sources of the transverse impedance using intensity dependent optics are presented. Some simulations using HEADTAIL to understand the limitations of the reconstruction and related numerical aspects are also discussed.
Date: May 4, 2009
Creator: Calaga, R.; Arduini, G.; Metral, E.; Papotti, G.; Quatraro, D.; Rumolo, G. et al.
Partner: UNT Libraries Government Documents Department
open access

CesrTA Retarding Field Analyzer Measurements in Drifts, Dipoles, Quadrupoles and Wigglers

Description: Over the course of the CesrTA program, the Cornell Electron Storage Ring (CESR) has been instrumented with several retarding field analyzers (RFAs), which measure the local density and energy distribution of the electron cloud. These RFAs have been installed in drifts, dipoles, quadrupoles, and wigglers; and data have been taken in a variety of beam conditions and bunch configurations. This paper will provide an overview of these results, and give a preliminary evaluation of the efficacy of clo… more
Date: June 15, 2010
Creator: Calvey, J. R.; Li, Y.; Livezey, J. A.; Makita, J.; Meller, R. E.; Palmer, M. A. et al.
Partner: UNT Libraries Government Documents Department
open access

Sps Ecloud Instabilities - Analysis of Machine Studies and Implications for Ecloud Feedback

Description: The SPS at high intensities exhibits transverse single-bunch instabilities with signatures consistent with an Ecloud driven instability. They present recent MD data from the SPS, details of the instrument technique and spectral analysis methods which help reveal complex vertical motion that develops within a subset of the injected bunch trains. The beam motion is detected via wideband exponential taper striplines and delta-sigma hybrids. The raw sum and difference data is sampled at 50 GHz with… more
Date: May 3, 2010
Creator: Fox, J. D.; Bullitt, A.; Mastorides, T.; Ndabashimiye, G.; Rivetta, C.; Turgut, O. et al.
Partner: UNT Libraries Government Documents Department
open access

E-Cloud Drivent Single-Bunch Instabilities in PS2

Description: One of the proposals under consideration for future upgrades of the LHC injector complex entails the replacement of the PS with the PS2, a longer circumference and higher energy synchrotron, with electron cloud effects representing a potentially serious limitation to the achievement of the upgrade goals. We report on ongoing numerical studies aiming at estimating the e-cloud density threshold for the occurrence of single bunch instabilities.
Date: May 23, 2010
Creator: Venturini, M.; Furman, M.; Penn, G.; Secondo, R.; Vay, J. L.; De Maria, R. et al.
Partner: UNT Libraries Government Documents Department
open access

Electron Clouds and Vacuum Pressure Rise in RHIC.

Description: The luminosity in RHIC is limited by vacuum pressure rises, observed with high intensity beams of all species (Au{sup 79+}, d{sup +}, p{sup +}). At injection, the pressure rise could be linked to the existence of electron clouds. In addition, pressure rises in the experimental regions may be caused by electron clouds. They review the existing observations, comparisons with simulations, as well as corrective measures taken and planned.
Date: April 19, 2004
Creator: Fischer, W.; Blaskiewicz, M.; He, P.; Huang, H.; Hseuh, H. C.; Iriso, U. et al.
Partner: UNT Libraries Government Documents Department
open access

A METHOD TO MEASURE THE SKEW QUADUPOLE STRENGTHS IN THE SIS-18 USING TWO BPMS.

Description: In the GSI synchrotron SIS-18 a new set of skew quadrupoles has been installed to improve the multi-turn-injection. Anew method based on the measurement of the resonance driving terms (RDT) has been proposed to cross-check the nominal values and polarities of their gradients. Once a beam is transversely kicked, it experiences oscillations whose spectrum contains both the betatron tune line and secondary lines. The amplitude of each line is proportional to the strength of the multipoles, such as… more
Date: July 5, 2004
Creator: FRANCHI,A. BEIER,T. KIRK,M. MORITZ,P. RUMOLO,G. TOMAS,R.
Partner: UNT Libraries Government Documents Department
open access

Accelerator Physics Code Web Repository

Description: In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this repository, illustrate its usage, and discuss our future plans, with emphasis on code benchmarking.
Date: October 24, 2006
Creator: Zimmermann, F.; Basset, R.; Bellodi, G.; Benedetto, E.; Dorda, U.; Giovannozzi, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Electron Cloud Build-up Study for DAFNE

Description: After the first experimental observations compatible with the presence of the e-cloud effect in the DAFNE positron ring, a more systematic study has been performed regarding the e-cloud build-up. The measured field map of the magnetic field has been taken into account in the simulation for elements present in the four 10 m long bending sections, representing 40% of the whole positron ring. The obtained simulation results are presented together with the recent experimental observations performed… more
Date: May 27, 2005
Creator: Vaccarezza, C.; Cimino, R.; Drago, A.; Zobov, M.; Bellodi, G.; Schulte, D. et al.
Partner: UNT Libraries Government Documents Department
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