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View article: Dis/Agreement and Recounting Variety in a Self-Managing Cola Collective
Dis/Agreement and Recounting Variety in a Self-Managing Cola Collective Open
This article explores the facilitation of productive disagreement within democratic spaces. The research shows that designing democratic organisations around both processes of agreement and spaces of disagreement go hand-in-hand as two sid…
View article: A Longitudinal Multibunch Feedback System Using Parallel Digital Signal Processors
A Longitudinal Multibunch Feedback System Using Parallel Digital Signal Processors Open
A programmable longitudinal feedback system based on four AT&T 1610 digital signal processors has been developed as a component of the PEP-II R&D program. This longitudinal quick prototype is a proof of concept for the PEP-II system and im…
View article: DOWN SAMPLED SIGNAL PROCESSING FOR A B FACTORY BUNCH BY BUNCH FEEDBACK SYSTEM
DOWN SAMPLED SIGNAL PROCESSING FOR A B FACTORY BUNCH BY BUNCH FEEDBACK SYSTEM Open
A bunch-by-bunch feedback scheme is studied for damping coupled bunch synchrotron oscillations in the proposed PEP II B Factory. The quasi-linear feedback systems design incorporates a phase detector to provide a quantized measure of bunch…
View article: Identification of the Inter-Bunch and Intra-Bunch Beam Dynamics Based on Dynamic Modal Decomposition (DMD)
Identification of the Inter-Bunch and Intra-Bunch Beam Dynamics Based on Dynamic Modal Decomposition (DMD) Open
The quantification of the Inter-bunch and Intra-bunch beam dynamics is important to define monitoring and operation tools in accelerators as well as to design model-based controllers to stabilize the transversal and longitudinal beam motio…
View article: Beam gap transient analysis and mitigations in high-current storage rings for an electron-ion collider
Beam gap transient analysis and mitigations in high-current storage rings for an electron-ion collider Open
The U.S. electron ion collider will utilize high current electron and ion storage rings with many bunches and large rf systems. Because of the dissimilarity of the two rings, the rf transients created by gaps or variations in the current d…
View article: The US Electron Ion Collider Accelerator Designs
The US Electron Ion Collider Accelerator Designs Open
With the completion of the National Academies of Sciences Assessment of a US Electron-Ion Collider, the prospects for construction of such a facility have taken a step forward. This paper provides an overview of the two site-specific EIC d…
View article: Transient Beam Loading and Mitigation in JLEIC Collider Rings
Transient Beam Loading and Mitigation in JLEIC Collider Rings Open
The Jefferson Lab Electron-Ion Collider (JLEIC) is an asymmetric high luminosity ring-ring collider proposed as the next major R facility for the nuclear physics community. Both of JLEIC’s electron and ion collider rings have high beam cur…
View article: Design Studies for a 10^36 SuperB-Factory
Design Studies for a 10^36 SuperB-Factory Open
A Super B Factory, an asymmetric etC collider with a luminosity of mi's, can provide a sensitive probe of new physics in the flavor sector of the Standard Model. The success of PEP-I1 and KEKB in producing unprecedented luminosity with unp…
View article: Control of Intra-Bunch Vertical Motion in the SPS with GHz Bandwidth Feedback
Control of Intra-Bunch Vertical Motion in the SPS with GHz Bandwidth Feedback Open
A GHz bandwidth vertical beam feedback system has been in development at the CERN SPS to explore control of unstable beam motion in single bunch and bunch train configurations. We present measurements and recent studies of stable and unsta…
View article: Optimal Operation of a Plug-In Hybrid Vehicle
Optimal Operation of a Plug-In Hybrid Vehicle Open
In this work, we present a convex optimization control method that has been shown in simulations to increase the fuel efficiency of a plug-in hybrid electric vehicle by over 10%. Using information on energy demand and energy use profiles, …
View article: Ultra-Wideband Transverse Intra-Bunch Feedback: Beginning Development of a Next Generation 8GSa/s System
Ultra-Wideband Transverse Intra-Bunch Feedback: Beginning Development of a Next Generation 8GSa/s System Open
Building on the success of our 4GSa/s wideband trans-verse feedback system, we have begun development of a next generation ultra-wideband feedback processor which doubles the effective sampling rate to 8GSa/s. This higher sampling rate and…
View article: The SPS Wideband Feedback Processor: A Flexible FPGA-Based Digital Signal Processing Demonstration Platform for Intra-Bunch Beam Stability Studies
The SPS Wideband Feedback Processor: A Flexible FPGA-Based Digital Signal Processing Demonstration Platform for Intra-Bunch Beam Stability Studies Open
A flexible digital signal processing platform based on FPGA technology has been developed for vertical intra-bunch beam stability studies at the CERN SPS. This system is unique in that samples at a very high rate (4GSa/s) in order to measu…
View article: Impact of a Wideband Feedback Prototype System on TMCI in the SPS
Impact of a Wideband Feedback Prototype System on TMCI in the SPS Open
The transverse mode coupling instability (TMCI) in the SPS has been identified as one of the potential performance limitations for future high intensity LHC beams that will be required for the High Luminosity (HL)-LHC era and is being addr…
View article: Recent Results from the Wideband Feedback System Tests at the SPS and Future Plans
Recent Results from the Wideband Feedback System Tests at the SPS and Future Plans Open
A high bandwidth transverse feedback demonstrator system has been devised within the LARP framework in collaboration with SLAC for the LHC Injectors Upgrade (LIU) Project. The initial system targeted the Super Proton Synchrotron (SPS) at C…
View article: Control of Intra-Bunch Vertical Instabilities at the SPS - Measurements and Technology Demonstration
Control of Intra-Bunch Vertical Instabilities at the SPS - Measurements and Technology Demonstration Open
We present recent measurements demonstrating control of unstable beam motion in single bunch and bunch train configurations at the SPS. The work is motivated by anticipated intensity increases from the LIU and HL-LHC upgrade programs, and …
View article: Bunch-by-Bunch Feedback Kickers for SPEAR3
Bunch-by-Bunch Feedback Kickers for SPEAR3 Open
SPEAR3 operates with a large cross-section copper vacuum chamber, mode-damped RF cavities and low-impedance insertion devices. As a result, the beam is passively stable for 280-bunch circulating beam current up to 500ma when the background…
View article: Simulation Results of a Feedback Control System to Damp Electron Cloud Single-Bunch Transverse Instabilities In The Cern SPS
Simulation Results of a Feedback Control System to Damp Electron Cloud Single-Bunch Transverse Instabilities In The Cern SPS Open
Transverse Single-Bunch Instabilities due to the Electron Cloud effect are limiting the operation at high current of the SPS at CERN. Recently a high-bandwidth Feedback System has been proposed as a possible solution to stabilize the beam …
View article: Wideband Vertical Intra-Bunch Feedback at the SPS - Technology Development, Recent Accelerator Measurements and Next Steps
Wideband Vertical Intra-Bunch Feedback at the SPS - Technology Development, Recent Accelerator Measurements and Next Steps Open
A wideband vertical intra-bunch feedback system is in development at the CERN SPS for use to control potential Ecloud and TMCI instabilities. The work is motivated by planned intensity increases from the LIU and HL-LHC upgrade programs. Sy…
View article: Recent Upgrades to the CERN SPS Wideband Intra-bunch Transverse Feedback Processor
Recent Upgrades to the CERN SPS Wideband Intra-bunch Transverse Feedback Processor Open
In support of the CERN High Luminosity LHC (HL-LHC) upgrade program, a research and development effort has been underway to understand and develop feedback control techniques for mitigating transverse intra-bunch instabilities in the SPS d…
View article: Identification of Intra-bunch Transverse Dynamics for Model-Based Control Purposes at CERN Super Proton Synchrotron
Identification of Intra-bunch Transverse Dynamics for Model-Based Control Purposes at CERN Super Proton Synchrotron Open
The high luminosity upgrade plan for the LHC (HiLumi-LHC) increases the bunch intensity and the ultimate intensities require mitigation of possible intra-bunch instabilities in the SPS. Feedback systems can stabilize intra-bunch dynamics. …
View article: Beam-Dynamics Issues in the FCC
Beam-Dynamics Issues in the FCC Open
The international Future Circular Collider (FCC) study is designing hadron, lepton and lepton-hadron colliders based on a new 100 km tunnel in the Geneva region. The main focus and ultimate goal of the study are high-luminosity proton-prot…
View article: A Formal Approach to the Design of Multibunch Feedback Systems: LQG Controllers
A Formal Approach to the Design of Multibunch Feedback Systems: LQG Controllers Open
We formulate the multibunch feedback problem as a stan-dard control-systems design problem and solve it using Linear Quadratic Gaussian (LQG) regulator theory. Use of a specific optimality criterion allows quantitative eval-uation of diffe…
View article: Identification of Intra-Bunch Transverse Dynamics for Model Based Wideband Feedback Control at CERN Super Proton Synchrotron
Identification of Intra-Bunch Transverse Dynamics for Model Based Wideband Feedback Control at CERN Super Proton Synchrotron Open
Multi-input multi-output (MIMO) feedback design techniques can be helpful to stabilize intra-bunch transverse instabilities induced by electron-clouds or transverse mode couplings at the CERN Super Proton Synchrotron (SPS). These MIMO tech…
View article: Wideband Vertical Intra-Bunch Feedback At The SPS - 2015 Results And Path Forward
Wideband Vertical Intra-Bunch Feedback At The SPS - 2015 Results And Path Forward Open
We present experimental measurements taken from CERN SPS machine development studies with a wideband intra-bunch feedback channel prototype. The demonstration system is a digital processing system with recently installed wideband kicker an…
View article: Upgrade and Operation of the Demonstration 4 GS/Sec. Intra-Bunch Instability Control System for the SPS
Upgrade and Operation of the Demonstration 4 GS/Sec. Intra-Bunch Instability Control System for the SPS Open
We present the expanded system implementation and operational experience details for the “Demo” technology platform commissioned at the SPS in January 2015. The system has been expanded during the LS1 shutdown with added features. The upgr…