IPAC2021 - List of Authors (Mertens, T.)

Paper	Title	Page
MOPAB126	BESSY III & MLS II - Status of the Development of the New Photon Science Facility in Berlin	451
	P. Goslawski, M. Abo-Bakr, F. Andreas, M. Arlandoo, J. Bengtsson, V. Dürr, K. Holldack, J.-G. Hwang, A. Jankowiak, B.C. Kuske, J. Li, A.N. Matveenko, T. Mertens, A. Meseck, E.C.M. Rial, M. Ries, M.K. Sauerborn, A. Schälicke, M. Scheer, P. Schnizer, L. Shi, J. Viefhaus HZB, Berlin, Germany J. Lüning UPMC, Paris, France
	HZB operates and develops two synchrotron radiation sources at Berlin Adlershof. The larger one, BESSY II with an energy of 1.7 GeV and 240 m circumference is optimized for soft-X rays and in operation since 1999. The smaller one is the MLS (Metrology Light Source), owned by the Physikalische Technische Bundesanstalt (PTB) - Germany’s National Metrology Institute. It is designed to fulfill the special metrology needs of the PTB with an energy of 0.6 GeV and 48 m circumference, covering the spectral range from THz and IR to EUV/VUV. In 2020 a discussion process has been started to define the requirements for successors of BESSY II and MLS and to study the possibilities integrate them into a new photon science facility in Berlin Adlershof. Here, we give a status report and present a first envisaged parameter space to both machines (see also MOPAB262, MOPAB220, MOPAB048, MOPAB242).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB126
About •	paper received ※ 18 May 2021 paper accepted ※ 24 June 2021 issue date ※ 18 August 2021
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TUPAB213	Important Drift Space Contributions to Non-Linear Beam Dynamics	1914
	J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries HZB, Berlin, Germany
	This paper presents an in-depth analysis of the non-linear contributions of drift spaces in beam dynamics for the creation of Transverse Resonance Island Buckets (TRIBs). TRIBs have been successfully generated in BESSY II and MLS at the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB). They offer the possibility of generating a second stable orbit and, by populating the orbit with a different electron bunch pattern, allow to effectively have two distinct radiation sources in the same machine individually tailored to different user needs. We demonstrate the generation of TRIBs by order of non-linearity on simple lattice configurations by only treating the drift space as the non-linear element. Moreover, we also insert other non-linear magnets to show how they modify the already generated TRIBs from the drift spaces. We conclude by giving a qualitative analysis of the occurring effects, which provides a guideline as to when the linear approximation is insufficient and the non-linear contribution has to be taken into account.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB213
About •	paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 29 August 2021
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TUPAB214	Alpha Buckets in Longitudinal Phase Space: A Bifurcation Analysis	1917
	J. Frank, M. Arlandoo, P. Goslawski, T. Mertens, M. Ries HZB, Berlin, Germany
	At HZB’s BESSY II and MLS facilities we have the ability to tune the momentum compaction factor α up to second non-linear order. The non-linear dependence α(δ) brings qualitative changes to the longitudinal phase space and introduces new fix points α(δ)=0 which produce the so-called α-buckets. We present with this paper an analysis of this phenomena from the standpoint of bifurcation theory. With this approach we were able to characterize the nature of the fix points and their position in direct dependence on the tunable parameters. Furthermore, we are able to place stringent conditions onto the tunable parameters to either create or destroy α-buckets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB214
About •	paper received ※ 12 May 2021 paper accepted ※ 17 June 2021 issue date ※ 26 August 2021
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TUPAB215	Novel Non-Linear Particle Tracking Approach Employing Lie Algebraic Theory in the TensorFlow Environment	1920
	J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries, L. Vera Ramirez HZB, Berlin, Germany
	With this paper we present first results for encoding Lie transformations as computational graphs in Tensorflow that are used as layers in a neural network. By implementing a recursive differentiation scheme and employing Lie algebraic arguments we were able to reproduce the diagrams for well known lattice configurations. We track through simple optical lattices that are encountered as the main constituents of accelerators and demonstrate the flexibility and modularity our approach offers. The neural network can represent the optical lattice with predefined coefficients allowing for particle tracking for beam dynamics or can learn from experimental data to fine-tune beam optics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB215
About •	paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 21 August 2021
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WEPAB317	Online Model Developments for BESSY II and MLS	3413
	P. Schnizer, J. Bengtsson, T. Birke, J. Li, T. Mertens, M. Ries, A. Schälicke, L. Vera Ramirez HZB, Berlin, Germany
	Digital models have been developed over a long time for preparing accelerator commissioning next to benchmarking theory predictions to machine measurements. These digital models are nowadays being realized as digital shadows or digital twins. Accelerator commissioning requires periodic setup and review of the machine status. Furthermore, different measurements are only practical by comparison to the machine model (e.g. beam based alignment). In this paper we describe the architecture chosen for our models, describe the framework Bluesky for measurement orchestration and report on our experience exemplifying on dynamic aperture scans. Furthermore we describe our plans to extend the models applied to BESSY~II and MLS to the currently planned machines BESSY~III and MLS~II.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB317
About •	paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 21 August 2021
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Paper

Title

Page

BESSY III & MLS II - Status of the Development of the New Photon Science Facility in Berlin

451

P. Goslawski, M. Abo-Bakr, F. Andreas, M. Arlandoo, J. Bengtsson, V. Dürr, K. Holldack, J.-G. Hwang, A. Jankowiak, B.C. Kuske, J. Li, A.N. Matveenko, T. Mertens, A. Meseck, E.C.M. Rial, M. Ries, M.K. Sauerborn, A. Schälicke, M. Scheer, P. Schnizer, L. Shi, J. Viefhaus
HZB, Berlin, Germany
J. Lüning
UPMC, Paris, France

HZB operates and develops two synchrotron radiation sources at Berlin Adlershof. The larger one, BESSY II with an energy of 1.7 GeV and 240 m circumference is optimized for soft-X rays and in operation since 1999. The smaller one is the MLS (Metrology Light Source), owned by the Physikalische Technische Bundesanstalt (PTB) - Germany’s National Metrology Institute. It is designed to fulfill the special metrology needs of the PTB with an energy of 0.6 GeV and 48 m circumference, covering the spectral range from THz and IR to EUV/VUV. In 2020 a discussion process has been started to define the requirements for successors of BESSY II and MLS and to study the possibilities integrate them into a new photon science facility in Berlin Adlershof. Here, we give a status report and present a first envisaged parameter space to both machines (see also MOPAB262, MOPAB220, MOPAB048, MOPAB242).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB126

About •

paper received ※ 18 May 2021 paper accepted ※ 24 June 2021 issue date ※ 18 August 2021

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

TUPAB213

Important Drift Space Contributions to Non-Linear Beam Dynamics

1914

J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries
HZB, Berlin, Germany

This paper presents an in-depth analysis of the non-linear contributions of drift spaces in beam dynamics for the creation of Transverse Resonance Island Buckets (TRIBs). TRIBs have been successfully generated in BESSY II and MLS at the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB). They offer the possibility of generating a second stable orbit and, by populating the orbit with a different electron bunch pattern, allow to effectively have two distinct radiation sources in the same machine individually tailored to different user needs. We demonstrate the generation of TRIBs by order of non-linearity on simple lattice configurations by only treating the drift space as the non-linear element. Moreover, we also insert other non-linear magnets to show how they modify the already generated TRIBs from the drift spaces. We conclude by giving a qualitative analysis of the occurring effects, which provides a guideline as to when the linear approximation is insufficient and the non-linear contribution has to be taken into account.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB213

About •

paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 29 August 2021

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

TUPAB214

Alpha Buckets in Longitudinal Phase Space: A Bifurcation Analysis

1917

J. Frank, M. Arlandoo, P. Goslawski, T. Mertens, M. Ries
HZB, Berlin, Germany

At HZB’s BESSY II and MLS facilities we have the ability to tune the momentum compaction factor α up to second non-linear order. The non-linear dependence α(δ) brings qualitative changes to the longitudinal phase space and introduces new fix points α(δ)=0 which produce the so-called α-buckets. We present with this paper an analysis of this phenomena from the standpoint of bifurcation theory. With this approach we were able to characterize the nature of the fix points and their position in direct dependence on the tunable parameters. Furthermore, we are able to place stringent conditions onto the tunable parameters to either create or destroy α-buckets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB214

About •

paper received ※ 12 May 2021 paper accepted ※ 17 June 2021 issue date ※ 26 August 2021

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

TUPAB215

Novel Non-Linear Particle Tracking Approach Employing Lie Algebraic Theory in the TensorFlow Environment

1920

J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries, L. Vera Ramirez
HZB, Berlin, Germany

With this paper we present first results for encoding Lie transformations as computational graphs in Tensorflow that are used as layers in a neural network. By implementing a recursive differentiation scheme and employing Lie algebraic arguments we were able to reproduce the diagrams for well known lattice configurations. We track through simple optical lattices that are encountered as the main constituents of accelerators and demonstrate the flexibility and modularity our approach offers. The neural network can represent the optical lattice with predefined coefficients allowing for particle tracking for beam dynamics or can learn from experimental data to fine-tune beam optics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB215

About •

paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 21 August 2021

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

WEPAB317

Online Model Developments for BESSY II and MLS

3413

P. Schnizer, J. Bengtsson, T. Birke, J. Li, T. Mertens, M. Ries, A. Schälicke, L. Vera Ramirez
HZB, Berlin, Germany

Digital models have been developed over a long time for preparing accelerator commissioning next to benchmarking theory predictions to machine measurements. These digital models are nowadays being realized as digital shadows or digital twins. Accelerator commissioning requires periodic setup and review of the machine status. Furthermore, different measurements are only practical by comparison to the machine model (e.g. beam based alignment). In this paper we describe the architecture chosen for our models, describe the framework Bluesky for measurement orchestration and report on our experience exemplifying on dynamic aperture scans. Furthermore we describe our plans to extend the models applied to BESSY~II and MLS to the currently planned machines BESSY~III and MLS~II.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB317

About •

paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 21 August 2021

Export •

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