NAPAC2016 - List of Authors (Hall, C.C.)

Paper	Title	Page
TUPOB13	Simulations of Space Charge Neutralization in a Magnetized Electron Cooler	511
	J. Gerity, P.M. McIntyre Texas A&M University, College Station, USA D.L. Bruhwiler, C.C. Hall RadiaSoft LLC, Boulder, Colorado, USA V. Moens EPFL, Lausanne, Switzerland C.S. Park, G. Stancari Fermilab, Batavia, Illinois, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award Number DE-SC0015212. Magnetized electron cooling at relativistic energies and Ampere scale current is essential to achieve the proposed ion luminosities in a future electron-ion collider (EIC). Neutralization of the space charge in such a cooler can significantly increase the magnetized dynamic friction and, hence, the cooling rate. The Warp framework is being used to simulate magnetized electron beam dynamics during and after the build up of neutralizing ions, via ionization of residual gas in the cooler. The design follows previous experiments at Fermilab as a verification case. We also discuss the relevance to EIC designs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB13
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WEA2IO02	Proposed Experimental Validation of Hamiltonian Perturbation Theory in IOTA
	D.L. Bruhwiler, N.M. Cook, C.C. Hall, R.A. Kishek, S.D. Webb RadiaSoft LLC, Boulder, Colorado, USA S. Nagaitsev, A.L. Romanov, A. Valishev Fermilab, Batavia, Illinois, USA
	The Integrable Optics Test Accelerator (IOTA) is a small ring under construction to explore advanced concepts in beam dynamics, initially with electron pencil beams to emulate single-particle dynamics and later with low-energy proton beams including significant space charge tune depression. Hamiltonian perturbation theory and simulations with Synergia, Warp and other codes are being used to develop an experimental program for beam dynamics, including the highly nonlinear 'elliptic' magnet originally proposed by Danilov and Nagaitsev. The results suggest a number of experiments that could be performed at IOTA. For example, small changes in the linear tune and the strength of the elliptic magnet can be used to control dynamic aperture. Both electron and proton beams can be used to measure the tune spread as a function of the elliptic magnet strength, for comparison with theory. Space charge driven halo formation due to envelope oscillations can be measured over a range of elliptic magnet strengths. Theoretical and computational results will be presented to guide future decisions regarding experimental diagnostics for IOTA.
	Slides WEA2IO02 [1.181 MB]
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WEA4CO02	Impact of Space Charge on Beam Dynamics and Integrability in the IOTA Ring
	C.C. Hall, D.L. Bruhwiler, N.M. Cook, R.A. Kishek, S.D. Webb RadiaSoft LLC, Boulder, Colorado, USA A.L. Romanov, A. Valishev Fermilab, Batavia, Illinois, USA
	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 DE-SC0011340. 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 low-energy 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.
	Slides WEA4CO02 [0.801 MB]
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THPOA23	Adaptive Matching of the IOTA Ring Linear Optics for Space Charge Compensation	1152
	A.L. Romanov, A. Valishev Fermilab, Batavia, Illinois, USA D.L. Bruhwiler, N.M. Cook, C.C. Hall RadiaSoft LLC, Boulder, Colorado, USA
	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 re-matching 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/JACoW-NAPAC2016-THPOA23
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THPOA37	Study of 2D CSR Effects in a Compression Chicane	1181
	C.C. Hall RadiaSoft LLC, Boulder, Colorado, USA S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA
	The study of coherent synchrotron radiation (CSR) has been an area of great interest because of its negative impact on FEL performance. The modeling of CSR is frequently performed using a 1D approximation, as 2D and 3D models can become extremely computational intensive. While experimental evidence is lacking in this area most studies show reasonable agreement between 1D and 2D CSR models for beam parameters in existing accelerators. In this work we focus on 2D modeling of CSR in a four-dipole chicane lattice based on the Jefferson Lab FEL. Comparison is shown between several models and measurement for energy loss due to CSR in the chicane. While good agreement is generally observed we also present investigation of several key differences observed in simulation. In particular, showing how the 1D and 2D CSR models deviate in regards to CSR and beam interaction within the drift spaces of the chicane and the downstream drift at the chicane end. E. Saldin, E. Schneidmiller, and M. Yurkov, Nucl. Instr. Meth. A398, 373 (1997).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA37
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Paper

Title

Page

Simulations of Space Charge Neutralization in a Magnetized Electron Cooler

511

J. Gerity, P.M. McIntyre
Texas A&M University, College Station, USA
D.L. Bruhwiler, C.C. Hall
RadiaSoft LLC, Boulder, Colorado, USA
V. Moens
EPFL, Lausanne, Switzerland
C.S. Park, G. Stancari
Fermilab, Batavia, Illinois, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award Number DE-SC0015212.
Magnetized electron cooling at relativistic energies and Ampere scale current is essential to achieve the proposed ion luminosities in a future electron-ion collider (EIC). Neutralization of the space charge in such a cooler can significantly increase the magnetized dynamic friction and, hence, the cooling rate. The Warp framework is being used to simulate magnetized electron beam dynamics during and after the build up of neutralizing ions, via ionization of residual gas in the cooler. The design follows previous experiments at Fermilab as a verification case. We also discuss the relevance to EIC designs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB13

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2IO02

Proposed Experimental Validation of Hamiltonian Perturbation Theory in IOTA

D.L. Bruhwiler, N.M. Cook, C.C. Hall, R.A. Kishek, S.D. Webb
RadiaSoft LLC, Boulder, Colorado, USA
S. Nagaitsev, A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA

The Integrable Optics Test Accelerator (IOTA) is a small ring under construction to explore advanced concepts in beam dynamics, initially with electron pencil beams to emulate single-particle dynamics and later with low-energy proton beams including significant space charge tune depression. Hamiltonian perturbation theory and simulations with Synergia, Warp and other codes are being used to develop an experimental program for beam dynamics, including the highly nonlinear 'elliptic' magnet originally proposed by Danilov and Nagaitsev. The results suggest a number of experiments that could be performed at IOTA. For example, small changes in the linear tune and the strength of the elliptic magnet can be used to control dynamic aperture. Both electron and proton beams can be used to measure the tune spread as a function of the elliptic magnet strength, for comparison with theory. Space charge driven halo formation due to envelope oscillations can be measured over a range of elliptic magnet strengths. Theoretical and computational results will be presented to guide future decisions regarding experimental diagnostics for IOTA.

Slides WEA2IO02 [1.181 MB]

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA4CO02

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

C.C. Hall, D.L. Bruhwiler, N.M. Cook, R.A. Kishek, S.D. Webb
RadiaSoft LLC, Boulder, Colorado, USA
A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA

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 DE-SC0011340.
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 low-energy 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.

Slides WEA4CO02 [0.801 MB]

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOA23

Adaptive Matching of the IOTA Ring Linear Optics for Space Charge Compensation

1152

A.L. Romanov, A. Valishev
Fermilab, Batavia, Illinois, USA
D.L. Bruhwiler, N.M. Cook, C.C. Hall
RadiaSoft LLC, Boulder, Colorado, USA

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 re-matching 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/JACoW-NAPAC2016-THPOA23

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOA37

Study of 2D CSR Effects in a Compression Chicane

1181

C.C. Hall
RadiaSoft LLC, Boulder, Colorado, USA
S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA

The study of coherent synchrotron radiation (CSR) has been an area of great interest because of its negative impact on FEL performance. The modeling of CSR is frequently performed using a 1D approximation*, as 2D and 3D models can become extremely computational intensive. While experimental evidence is lacking in this area most studies show reasonable agreement between 1D and 2D CSR models for beam parameters in existing accelerators. In this work we focus on 2D modeling of CSR in a four-dipole chicane lattice based on the Jefferson Lab FEL. Comparison is shown between several models and measurement for energy loss due to CSR in the chicane. While good agreement is generally observed we also present investigation of several key differences observed in simulation. In particular, showing how the 1D and 2D CSR models deviate in regards to CSR and beam interaction within the drift spaces of the chicane and the downstream drift at the chicane end.
*E. Saldin, E. Schneidmiller, and M. Yurkov, Nucl. Instr. Meth. A398, 373 (1997).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA37

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