Paper  Title  Page 

WEA4CO02 
Impact of Space Charge on Beam Dynamics and Integrability in the IOTA Ring  


Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DESC0011340. Modern hadron accelerators such as spallation sources and neutrino factories must push the intensity limits to meet increasingly challenging goals. The Integrable Optics Test Accelerator (IOTA) is a small ring, currently under construction at Fermilab, which will explore advanced concepts in beam dynamics with lowenergy proton beams with high space charge tune depression. Through use of a special nonlinear magnet insertion, large tune spread with amplitude can be achieved while preserving two integrals of motion for the single particle behavior. The tune shift and spread induced by space charge can disrupt the stability of these invariants. In this work we examine the behavior of these invariants in the presence of space charge. Simulations of a modified IOTA lattice that accounts for the space charge tune depression are shown, and the behavior of the invariants is examined. 

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WEA4CO03  Intrinsic Landau Damping of Space Charge Modes at Coupling Resonance  863 


Funding: This work was performed at Fermilab, operated by Fermi Research Alliance, LLC under Contract No. DEAC0207CH11359 with the United States Department of Energy. Using Synergia accelerator modeling package and Dynamic Mode Decomposition technique, the properties of the first transverse dipole mode in Gaussian bunches with space charge are compared at transverse coupling resonance and offresonance. The Landau damping at coupling resonance and in the strong space charge regime is a factor of two larger, while the mode's tune and shape are nearly the same. While the damping mechanism in the offresonance case fits well with the classical Landau damping paradigm, the enhancement at coupling resonance is due to a higher order modeparticle coupling term which is modulated by the amplitude oscillation of the resonance trapped particles. 

Slides WEA4CO03 [3.422 MB]  
DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWNAPAC2016WEA4CO03  
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WEA4CO04 
Suppression of HalfInteger Resonance in FNAL Booster and Space Charge Losses at Injection  


Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DEAC0207CH11359 with the United States Department of Energy. The particle losses at injection in the FNAL Booster are one of the major factors limiting the machine performance. The losses are caused by motion nonlinearity due to direct space charge and due to nonlinearity introduced by large values of chromaticity sextupoles required to suppress transverse instabilities. The report aims to address the former  the suppression of incoherent space charge effects by reducing deviations from the perfect periodicity of linear optics functions. It should be achieved by high accuracy optics measurements with subsequent optics correction and by removing known sources of optics perturbations. The study shows significant impact on halfinteger stop band with subsequent reduction of particle loss. We use realistic Booster lattice model to understand the present limitations, and investigate the possible improvements which would allow high intensity operation with PIPII parameters. 

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THPOA19  Design Considerations for Proposed Fermilab Integrable RCS  1138 


Integrable optics is an innovation in particle accelerator design that provides strong nonlinear focusing while avoiding parametric resonances. One promising application of integrable optics is to overcome the traditional limits on accelerator intensity imposed by betatron tunespread and collective instabilities. The efficacy of highintensity integrable accelerators will be undergo comprehensive testing over the next several years at the Fermilab Integrable Optics Test Accelerator (IOTA) and the University of Maryland Electron Ring (UMER). We propose an integrable RCS (iRCS) as a replacement for the Fermilab Booster to achieve multiMW beam power for the Fermilab highenergy neutrino program. We provide a overview of the machine parameters and discuss an approach to lattice optimization. Integrable optics requires arcs with integerpi phase advance followed by drifts with matched beta functions. We provide an example integrable lattice with features of a modern RCS  long dispersionfree drifts, low momentum compaction, superperiodicity, chromaticity correction, separatefunction magnets, and bounded beta functions.  
DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWNAPAC2016THPOA19  
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THPOA23  Adaptive Matching of the IOTA Ring Linear Optics for Space Charge Compensation  1152 


Many present and future accelerators must operate with high intensity beams when distortions induced by space charge forces are among major limiting factors. Betatron tune depression of above approximately 0.1 per cell leads to significant distortions of linear optics. Many aspects of machine operation depend on proper relations between lattice functions and phase advances, and can be improved with proper treatment of space charge effects. We implement an adaptive algorithm for linear lattice rematching with full account of space charge in the linear approximation for the case of Fermilab's IOTA ring. The method is based on a search for initial second moments that give closed solution and, at the same time, satisfy predefined set of goals for emittances, beta functions, dispersions and phase advances at and between points of interest. Iterative singular value decomposition based technique is used to search for optimum by varying wide array of model parameters.  
DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWNAPAC2016THPOA23  
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