IPAC2014 - List of Authors (Laface, E.)

Paper	Title	Page
TUPRO061	Benchmarking Beam Envelope Models for the European Spallation Source	1174
	I. List Cosylab, Ljubljana, Slovenia E. Laface ESS, Lund, Sweden
	TraceWin is used at the European Spallation Source (ESS) as the design tool, while fast and accurate on-line models will be needed during the operations. Three models are compared: the ESS Linac Simulator (ELS), TraceWin and the OpenXAL. In all of the benchmarked models, dynamics of each beam-line element is, to the first order, represented by a transfer matrix. Differences in the matrices occur, since different reference frames are used and as well different assumptions about the energy of the particles are made. General transformations of the reference frames will be presented. Using those, the comparison of transfer maps among TraceWin and OpenXAL are given. When the differences between TraceWin and OpenXAL were unclear, the benchmark versus other code, like MAD-X and Dynac was done. The best implementations were combined into a new on-line model implementation Java ELS (or JELS) and at last the comparison of the latter with TraceWin is given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO061
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THPRO072	Field Parametrisation for the ESS Superconducting Cavities	3044
	T. Lindqvist Lund University, Lund, Sweden E. Laface ESS, Lund, Sweden
	Here we present a method for constructing a parametrization of the electric field in the superconducting elliptic cavities of the ESS linac. The parametrization is done by replicating the electric field from measured data using trigonometric and exponential functions. The field generated by the parameters exhibits a mean error of 0.28% ( maximum error of 3.8% and s.t.d. error 1.1%), with the advantage of only taking up a fraction of the required data. The field in the entire cavity is extrapolated by combining the Maxwell equations with the parametrized form of the field. We also present particle simulations based on the parametrization model to showcase some typical accelerator behaviour. Additionally we present a small extension of the parametrization method to also model spoke cavities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO072
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THPRO073	Longitudinal Acceptance Evaluation from Hamiltonian	3047
	E. Laface ESS, Lund, Sweden
	An RF cavity is designed around a reference particle; if the energy or the phase of a real particle are too far from the reference, the particle is lost. The widest area of energy-phase that allows a particle to be transported by the cavity is called acceptance of the cavity. In simulations the acceptance is evaluated tracking several particles with different energies and phases and marking when a particle is transmitted or lost. This process can be time consuming because of the large amount of tracked particles requested to characterise the cavity acceptance. In this paper we propose an alternative method to evaluate the acceptance studying directly the Hamiltonian associated to the cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO073
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THPME047	Sorting in the ESS	3329
	S. Peggs, E. Laface, E. Sargsyan, R. Zeng ESS, Lund, Sweden
	Sorting optical elements has significant potential during the construction of superconducting linacs like the ESS, in the same way that it has proved to be very effective in circular accelerators like RHIC and the LHC. In the linac domain, the elements of primary interest are cavities and cryomodules, instead of the magnets (of all sorts) that are routinely sorted in circular accelerators. Multiple cavities can be sorted to optimise individual cryomodules, and cryomodules can be sorted into optimised locations within the tunnel. Different sorting strategies are discussed and preliminarily evaluated in this paper. Central to the evaluation is the identification of goal (or penalty) functions that are maximised (or minimised), and which can be rapidly quantified by simulation. Also crucial is the availability of a modeling system that is realistic in its complex representation of the linac, and which can easily be modified and developed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME047
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Paper

Title

Page

Benchmarking Beam Envelope Models for the European Spallation Source

1174

I. List
Cosylab, Ljubljana, Slovenia
E. Laface
ESS, Lund, Sweden

TraceWin is used at the European Spallation Source (ESS) as the design tool, while fast and accurate on-line models will be needed during the operations. Three models are compared: the ESS Linac Simulator (ELS), TraceWin and the OpenXAL. In all of the benchmarked models, dynamics of each beam-line element is, to the first order, represented by a transfer matrix. Differences in the matrices occur, since different reference frames are used and as well different assumptions about the energy of the particles are made. General transformations of the reference frames will be presented. Using those, the comparison of transfer maps among TraceWin and OpenXAL are given. When the differences between TraceWin and OpenXAL were unclear, the benchmark versus other code, like MAD-X and Dynac was done. The best implementations were combined into a new on-line model implementation Java ELS (or JELS) and at last the comparison of the latter with TraceWin is given.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO061

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

THPRO072

Field Parametrisation for the ESS Superconducting Cavities

3044

T. Lindqvist
Lund University, Lund, Sweden
E. Laface
ESS, Lund, Sweden

Here we present a method for constructing a parametrization of the electric field in the superconducting elliptic cavities of the ESS linac. The parametrization is done by replicating the electric field from measured data using trigonometric and exponential functions. The field generated by the parameters exhibits a mean error of 0.28% ( maximum error of 3.8% and s.t.d. error 1.1%), with the advantage of only taking up a fraction of the required data. The field in the entire cavity is extrapolated by combining the Maxwell equations with the parametrized form of the field. We also present particle simulations based on the parametrization model to showcase some typical accelerator behaviour. Additionally we present a small extension of the parametrization method to also model spoke cavities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO072

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

THPRO073

Longitudinal Acceptance Evaluation from Hamiltonian

3047

E. Laface
ESS, Lund, Sweden

An RF cavity is designed around a reference particle; if the energy or the phase of a real particle are too far from the reference, the particle is lost. The widest area of energy-phase that allows a particle to be transported by the cavity is called acceptance of the cavity. In simulations the acceptance is evaluated tracking several particles with different energies and phases and marking when a particle is transmitted or lost. This process can be time consuming because of the large amount of tracked particles requested to characterise the cavity acceptance. In this paper we propose an alternative method to evaluate the acceptance studying directly the Hamiltonian associated to the cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO073

Export •

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

THPME047

Sorting in the ESS

3329

S. Peggs, E. Laface, E. Sargsyan, R. Zeng
ESS, Lund, Sweden

Sorting optical elements has significant potential during the construction of superconducting linacs like the ESS, in the same way that it has proved to be very effective in circular accelerators like RHIC and the LHC. In the linac domain, the elements of primary interest are cavities and cryomodules, instead of the magnets (of all sorts) that are routinely sorted in circular accelerators. Multiple cavities can be sorted to optimise individual cryomodules, and cryomodules can be sorted into optimised locations within the tunnel. Different sorting strategies are discussed and preliminarily evaluated in this paper. Central to the evaluation is the identification of goal (or penalty) functions that are maximised (or minimised), and which can be rapidly quantified by simulation. Also crucial is the availability of a modeling system that is realistic in its complex representation of the linac, and which can easily be modified and developed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME047

Export •

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