IPAC2015 - List of Authors (Nash, B.)

Paper	Title	Page
MOPWA013	Modeling and Measurements of Spin Depolarization	109
	N. Carmignani, F. Ewald, L. Farvacque, B. Nash, P. Raimondi ESRF, Grenoble, France
	An electron bunch in a storage ring becomes spin polarized due to the Sokolov-Ternov effect. The beam may then be depolarized by applying a horizontal magnetic field oscillating in resonance with the spin tune. This technique has been used to measure the electron energy at numerous synchrotrons. In this paper, we report on modeling and measurements of the polarization and depolarization process at the ESRF. We report the results of a Matlab based parallelized spin tracking code that we developed for these studies. We show the change in depolarization resulting as different physical effects are added to the model.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA013
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MOPWA014	New Functionality for Beam Dynamics in Accelerator Toolbox (AT)	113
	B. Nash, N. Carmignani, L. Farvacque, S.M. Liuzzo, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White ESRF, Grenoble, France
	Accelerator Toolbox is a widely used code for beam dynamic simulations based on Matlab. To continue the development of the code in a collaborative manner, a SourceForge project and SVN repository called atcollab has been established. Here we describe the contributions to atcollab from the ESRF beam dynamics group. Additional modules have been developed: general matching (atmatch), improved plotting (atplot), Touschek lifetime computation via the Piwinski formula, nonlinear dynamics computations such as resonance driving terms, improved reporting of lost particles and improvements and additions to the integration routines. One example of the latter includes diffusion due to quantum fluctuations. Modeling of collective effects may now be performed using pass methods representing a variety of impedance models. Finally, routines to replace the full ring with a compact representation have been developed, facilitating studies in which many turns and many particles are required.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA014
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TUPWA013	Linear and Nonlinear Optimizations for the ESRF Upgrade Lattice	1422
	N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White ESRF, Grenoble, France
	The ESRF storage ring will be replaced in 2020 by a new hybrid multi bend achromat lattice with 134 pmrad equilibrium horizontal emittance. To determine the best working point, large scans of tunes and chromaticities have been performed, computing Touschek lifetime and dynamic aperture. From different working points, the multi-objective genetic algorithm NSGA-II has been used to optimize the nonlinear magnets values and some linear optics parameters. The analysis have been carried out on lattices with errors and corrections. The optimizations have produced lattices with longer lifetime and larger dynamic aperture for different working points with positive chromaticities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA013
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TUPWA014	Influence of errors on the ESRF Upgrade Lattice	1426
	S.M. Liuzzo, J.C. Biasci, N. Carmignani, L. Farvacque, G. Gatta, G. Le Bec, D. Martin, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White ESRF, Grenoble, France
	To determine the tolerable alignment and magnetic errors for the ESRF upgrade, we study their influence on Touschek lifetime and dynamic aperture. The correction of each set of errors studied is performed with a commissioning-like procedure, from the search for a closed orbit to the correction of resonance driving terms. Each kind of error is studied independently for each relevant family of magnets. The tolerable values deduced from the analysis are within the practical limits. The impact of the measured and simulated survey errors is also considered, defining the position of the currently installed lattice as the one of least impact for the realignment of X-ray beamlines.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA014
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TUPWA016	Modeling of beam losses at ESRF	1430
	R. Versteegen, P. Berkvens, N. Carmignani, J. Chavanne, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, K.B. Scheidt, S.M. White ESRF, Grenoble, France
	As the ESRF enters the second phase of its upgrade towards ultra low emittance, the knowledge of the beam loss pattern around the storage ring is needed for radiation safety calculations and for the new machine design optimization. A model has been developed to simulate the Touschek scattering and the scattering of electrons on residual gas nuclei in view of producing a detailed loss map of the machine. Results of simulation for the ESRF are presented and compared with real beam measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA016
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TUPWA017	Collimation scheme for the ESRF Upgrade	1434
	R. Versteegen, P. Berkvens, N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, S.M. White ESRF, Grenoble, France
	The ultra low emittance foreseen for the ESRF Upgrade will translate into a limited Touschek lifetime, increasing substantially the loss rate around the ring compared to the present machine. Consequently it becomes crucial to know the distribution of electron beam losses to optimize the radiation shielding and to protect the insertion devices from radiation damage. Such loss maps of the storage ring can be produced thanks to the simulation of the Touschek scattering process along the lattice. It is shown that about 80 % of the beam losses can be collimated in a few chosen locations only, keeping the resulting lifetime reduction smaller than 10 %.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA017
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Paper

Title

Page

Modeling and Measurements of Spin Depolarization

109

N. Carmignani, F. Ewald, L. Farvacque, B. Nash, P. Raimondi
ESRF, Grenoble, France

An electron bunch in a storage ring becomes spin polarized due to the Sokolov-Ternov effect. The beam may then be depolarized by applying a horizontal magnetic field oscillating in resonance with the spin tune. This technique has been used to measure the electron energy at numerous synchrotrons. In this paper, we report on modeling and measurements of the polarization and depolarization process at the ESRF. We report the results of a Matlab based parallelized spin tracking code that we developed for these studies. We show the change in depolarization resulting as different physical effects are added to the model.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA013

Export •

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

MOPWA014

New Functionality for Beam Dynamics in Accelerator Toolbox (AT)

113

B. Nash, N. Carmignani, L. Farvacque, S.M. Liuzzo, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

Accelerator Toolbox is a widely used code for beam dynamic simulations based on Matlab. To continue the development of the code in a collaborative manner, a SourceForge project and SVN repository called atcollab has been established. Here we describe the contributions to atcollab from the ESRF beam dynamics group. Additional modules have been developed: general matching (atmatch), improved plotting (atplot), Touschek lifetime computation via the Piwinski formula, nonlinear dynamics computations such as resonance driving terms, improved reporting of lost particles and improvements and additions to the integration routines. One example of the latter includes diffusion due to quantum fluctuations. Modeling of collective effects may now be performed using pass methods representing a variety of impedance models. Finally, routines to replace the full ring with a compact representation have been developed, facilitating studies in which many turns and many particles are required.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA014

Export •

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

TUPWA013

Linear and Nonlinear Optimizations for the ESRF Upgrade Lattice

1422

N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

The ESRF storage ring will be replaced in 2020 by a new hybrid multi bend achromat lattice with 134 pmrad equilibrium horizontal emittance. To determine the best working point, large scans of tunes and chromaticities have been performed, computing Touschek lifetime and dynamic aperture. From different working points, the multi-objective genetic algorithm NSGA-II has been used to optimize the nonlinear magnets values and some linear optics parameters. The analysis have been carried out on lattices with errors and corrections. The optimizations have produced lattices with longer lifetime and larger dynamic aperture for different working points with positive chromaticities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA013

Export •

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

TUPWA014

Influence of errors on the ESRF Upgrade Lattice

1426

S.M. Liuzzo, J.C. Biasci, N. Carmignani, L. Farvacque, G. Gatta, G. Le Bec, D. Martin, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

To determine the tolerable alignment and magnetic errors for the ESRF upgrade, we study their influence on Touschek lifetime and dynamic aperture. The correction of each set of errors studied is performed with a commissioning-like procedure, from the search for a closed orbit to the correction of resonance driving terms. Each kind of error is studied independently for each relevant family of magnets. The tolerable values deduced from the analysis are within the practical limits. The impact of the measured and simulated survey errors is also considered, defining the position of the currently installed lattice as the one of least impact for the realignment of X-ray beamlines.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA014

Export •

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

TUPWA016

Modeling of beam losses at ESRF

1430

R. Versteegen, P. Berkvens, N. Carmignani, J. Chavanne, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, K.B. Scheidt, S.M. White
ESRF, Grenoble, France

As the ESRF enters the second phase of its upgrade towards ultra low emittance, the knowledge of the beam loss pattern around the storage ring is needed for radiation safety calculations and for the new machine design optimization. A model has been developed to simulate the Touschek scattering and the scattering of electrons on residual gas nuclei in view of producing a detailed loss map of the machine. Results of simulation for the ESRF are presented and compared with real beam measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA016

Export •

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

TUPWA017

Collimation scheme for the ESRF Upgrade

1434

R. Versteegen, P. Berkvens, N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, S.M. White
ESRF, Grenoble, France

The ultra low emittance foreseen for the ESRF Upgrade will translate into a limited Touschek lifetime, increasing substantially the loss rate around the ring compared to the present machine. Consequently it becomes crucial to know the distribution of electron beam losses to optimize the radiation shielding and to protect the insertion devices from radiation damage. Such loss maps of the storage ring can be produced thanks to the simulation of the Touschek scattering process along the lattice. It is shown that about 80 % of the beam losses can be collimated in a few chosen locations only, keeping the resulting lifetime reduction smaller than 10 %.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA017

Export •

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