IPAC2022 - Classification: MC2: Photon Sources and Electron Accelerators / T15: Undulators and Wigglers

Paper	Title	Page
WEIYSP1	New Designs of Short-Period Undulators for Producing High-Brightness Radiation in Synchrotron Light Sources	1624
	E.J. Wallén LBNL, Berkeley, California, USA
	We review modern state-of-the-art and new concepts of undulators planned for new generation light sources. Both superconducting and permanent-magnet-based insertion devices feature unique solutions to reach high precisely tunable fields in the period range of 10^-18 mm, 2-4 meters in length and with the ID gaps of less than 5 mm. The same quest for small gaps and shortest possible period length exists also for elliptically polarizing undulators. A review of new designs in Europe, Asia and Americas will be in the focus of this presentation.
	Slides WEIYSP1 [21.171 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIYSP1
About •	Received ※ 15 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 07 July 2022
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THPOPT002	Beam Power Deposition on the Cryogenic Permanent Magnet Undulator	2556
	L.R. Carver, C. Benabderrahmane, P. Brumund, N. Carmignani, J. Chavanne, G. Le Bec, R. Versteegen, S.M. White ESRF, Grenoble, France
	X-rays with high brilliance and low phase errors are generated in the Cryogenic Permanent Magnet Undulator (CPMU) currently in use at the ESRF. In the event of a failure of the cryogenic cooling the beam will continue to deposit power into the module, even when the undulator jaws are fully opened. This could lead to unacceptably high heating of the magnet blocks which could cause their demagnetisation. Impedance simulations were performed using IW2D and CST to compute the power deposited by the beam in both the closed and open jaw settings. This was followed by thermal simulations to compute the expected temperature rise. These results will help advise the operational procedure in the event of a cooling failure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT002
About •	Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022
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THPOPT032	SUNDAE2 at EuXFEL: A Test Stand to Characterize the Magnetic Field of Superconducting Undulators	2649
	J.E. Baader, S. Abeghyan, S. Casalbuoni, D. La Civita, B. Marchetti, M. Yakopov, P. Ziolkowski EuXFEL, Schenefeld, Germany H.-J. Eckoldt, A. Hauberg, S. Lederer, L. Lilje, T. Wohlenberg, R. Zimmermann DESY, Hamburg, Germany A.W. Grau KIT, Eggenstein-Leopoldshafen, Germany
	European XFEL foresees a superconducting undulator (SCU) afterburner in the SASE2 hard X-ray beamline. It consists of six 5m-long undulator modules with a 5mm vacuum gap, where each module contains two 2m-long coils and one phase shifter. Prior to installation, the magnetic field must be mapped appropriately. Two magnetic measurement test stands named SUNDAE 1 and 2 (Superconducting UNDulAtor Experiment) are being developed at European XFEL. While SUNDAE1 will be a vertical test stand to measure SCU coils up to two meters with Hall probes in a liquid or superfluid helium bath, SUNDAE2 will measure the SCU coils assembled in the final cryostat. This contribution presents the development status of SUNDAE2 and its main requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT032
About •	Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022
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THPOPT050	Development and Construction of Cryogenic Permanent Magnet Undulators for ESRF-EBS	2712
	C. Benabderrahmane, P. Brumund, J. Chavanne, D. Coulon, G. Le Bec, B. Ogier, R. Versteegen ESRF, Grenoble, France
	The ESRF Extremely Brilliant Source (ESRF-EBS) is on operation for Users since August 2020 after 20 months of shutdown. This first of a kind fourth generation high energy synchrotron is based on a Hybrid Multi-Bend Achromat lattice. The main goal of the ESRF-EBS is to reduce the horizontal emittance, which leads to a signifi-cant increase of the X-ray source brilliance. To cover the intensive demand of short period small gap undulators at ESRF-EBS, a new design for a 2 m Cryogenic Permanent Magnet Undulator (CPMU) has been developed. Six CPMUs will be installed in the next years; the first two CPMUs have been constructed and actually used on ID15 and ID16 beamline, the third one is under con-structing. An intensive refurbishment work has been done on the existing insertion devices to adapt them to the new accelerator which has shorter straight section and closer dipoles to the IDs than in the old one. This contribution will review the development, construc-tion and commissioning of the new CPMUs, and the refurbishment work done on the existing ones to adapt them to the new accelerator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT050
About •	Received ※ 02 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 18 June 2022
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THPOPT052	The Status of the In-Vacuum-APPLE II Undulator IVUE32 at HZB / BESSY II	2716
	J. Bahrdt, J. Bakos, S. Gaebel, S. Gottschlich, S. Grimmer, S. Knaack, C. Kuhn, F. Laube, A. Meseck, C. Rethfeldt, E.C.M. Rial, A. Rogosch-Opolka, M. Scheer, P.I. Volz HZB, Berlin, Germany
	At BESSY II, two new beamlines for RIXS and for X-Ray-microscopy demand a short period variably polarizing undulator. For this purpose, the first in-vacuum APPLE undulator worldwide is under construction. The parameters are as follows: period length=32mm, magnetic length=2500mm, minimum gap=7mm. The design incorporates a force compensation scheme as proposed by two of the authors at the SRI2018. All precision parts of the drive chain are located in air. New transverse slides for the transversal slit adjustment have been developed and tested. Optical micrometers measure the gap and shift positions, similar to the system of the CPMU17 at BESSY II. They provide the signals for motor feedback loops. A new UHV-compatible soldering technique, as developed with industry, relaxes fabrication tolerances of magnets and magnet holders and simplifies the magnet assembly. A 10-period prototype has been setup for lifetime tests of the new magnetic keeper design. The paper describes first results of the prototype and other key-components and summarizes the status of the full-scale undulator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT052
About •	Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 22 June 2022
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THPOPT053	Goubau-Line Set Up for Bench Testing Impedance of IVU32 Components	2719
SUSPMF023	use link to see paper's listing under its alternate paper code
	P.I. Volz, A. Meseck HZB, Berlin, Germany A. Meseck KPH, Mainz, Germany
	The worldwide first in-vacuum elliptical undulator, IVUE32, is being developed at Helmholtz-Zentrum Berlin. The 2.5 m long device with a period length of 3.2 cm and a minimum gap of about 7 mm is to be installed in the BESSY II storage ring. It will deliver radiation in the soft X-ray range to several beamlines. The proximity of the undulator structure to the electron beam makes the device susceptible to wakefield effects which can influence beam stability. A complete understanding of its impedance characteristics is required prior to installation and operation, as unforeseen heating of components could have catastrophic consequences. To understand and measure the IVU’s impedance characteristics a Goubau-Line test stand is being designed. A Goubau-line is a single wire transmission line for high frequency surface waves with a transverse electric field resembling that of a charged particle beam out to a certain radial distance. A concept optimized for bench testing IVUE32-components will be discussed, microwave simulations will be presented together with first measurements from a test stand prototype.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT053
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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THPOPT058	Status and Powering Test Results of HTS Undulator Coils at 77 K for Compact FEL Designs	2726
SUSPMF024	use link to see paper's listing under its alternate paper code
	S.C. Richter, A. Bernhard, A.-S. Müller KIT, Karlsruhe, Germany A. Ballarino, T.H. Nes, S.C. Richter, D. Schoerling CERN, Meyrin, Switzerland
	Funding: This work has been supported by the Wolfgang Gentner Program of the German Federal Ministry of Education and Research (grant no. 05E18CHA). The production of low emittance positron beams for future linear and circular lepton colliders, like CLIC or FCC-ee, requires high-field damping wigglers. Just as compact free-electron lasers (FELs) require high-field but as well short-period undulators to emit high energetic, coherent photons. Using high-temperature superconductors (HTS) in the form of coated ReBCO tape superconductors allows higher magnetic field amplitudes at 4 K and larger operating margins as compared to low-temperature superconductors, like Nb-Ti. This contribution discusses the development work on superconducting vertical racetrack (VR) undulator coils, wound from coated ReBCO tape superconductors. The presented VR coils were modularly designed with a period length of 13 mm. Powering tests in liquid nitrogen of multiple vertical racetrack coils were performed at CERN. The results from the measurements are presented for three VR coils and compared with electromagnetic simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT058
About •	Received ※ 17 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 21 June 2022
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THPOPT060	Tolerance Study on the Geometrical Errors for a Planar Superconducting Undulator	2734
	V. Grattoni, S. Casalbuoni, B. Marchetti EuXFEL, Schenefeld, Germany
	At the European XFEL, a superconducting afterburner is considered for the SASE2 hard X-ray beamline. It will consist of six undulator modules. Within each module, two superconducting undulators (SCU) 2 m long are present. Such an afterburner will enable photon energies above 30 keV. A high field quality of the SCU is crucial to guarantee the quality of the electron beam trajectory, which is directly related to the spectral quality of the emitted free-electron laser (FEL) radiation. Therefore, the effects of the SCU’s mechanical imperfections on the resultant magnetic field have to be carefully characterized. In this contribution, we present possible mechanical errors affecting the undulator structure, and we perform an analytical study aimed at determining the tolerances on these errors for our SCUs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT060
About •	Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 27 June 2022
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THPOPT061	European XFEL Undulators - Status and Plans	2737
	S. Casalbuoni, S. Abeghyan, J.E. Baader, U. Englisch, V. Grattoni, S. Karabekyan, B. Marchetti, H. Sinn, F. Wolff-Fabris, M. Yakopov, P. Ziolkowski EuXFEL, Schenefeld, Germany
	European XFEL has three undulator lines based on permanent magnet technology: two for hard and one for soft X-rays. The planar undulators can be tuned to cover the acceptance in terms of photon beam energy of the respective photon beamlines: 3.6-25 keV (SASE1/2) and 0.25-3 keV (SASE3) by changing the electron energy range between 11.5 GeV and 17.5 GeV and/or the undulator gap. In order to obtain different polarization modes, as required by the soft X-ray beamlines, a helical afterburner consisting of four APPLE X undulators designed by PSI has been installed at the downstream end of the present SASE3 undulator system. The European XFEL plans to develop the technology of superconducting undulators, which is of strategic importance for the facility upgrade. In order to extend the energy range above 30 keV a superconducting undulator afterburner is foreseen to be installed at the end of SASE2. This contribution presents the current status and the planned upgrades of the undulator lines at European XFEL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT061
About •	Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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THPOPT063	Design of Scilab Xcos Simulation Model for Pulsed Wire Method Data Analyses	2741
	H. Jeevakhan NITTTR, Bhopal, India S.M. Khan, G. Mishra Devi Ahilya University, Indore, India
	Pulsed wire method (PWM)is used for undulator characterisation. Scilab Xcos simulation model is designed for the analyses of data obtained by PWM. The data obtained from PWM is given as input to the model and its output gives the magnetic field of the undulator. Scilab Xcos model can also be utilized for determining the phase error of the undulator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT063
About •	Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 09 July 2022
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THPOPT064	Hall Probe Magnetic Measurement of 50 mm Period PPM Undulator	2744
SUSPMF025	use link to see paper's listing under its alternate paper code
	S.M. Khan, G. Mishra Devi Ahilya University, Indore, India M. Gehlot MAX IV Laboratory, Lund University, Lund, Sweden H. Jeevakhan NITTTR, Bhopal, India
	In this paper, we present the latest upgradation of Hall Probe magnetic measurement system. The Hall Probe measurement system is upgraded with position measuring detectors and 3D F.W. Bell Teslameter. The field integrals and the phase errors are calculated with a new user friendly MATLAB code. The integrated multipoles both normal and skew components are measured and discussed in the paper. The proposed activities on 300 mm length prototype asymmetric undulator and 50 mm quasi period, six period length at Laser Instrumentation and Insertion Device Application laboratory of Devi Ahilya Vishwa Vidyalaya (DAVV), Indore, India has been discussed and design components are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT064
About •	Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 22 June 2022
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THPOPT066	Helical Wiggler Design for Optical Stochastic Cooling at CESR	2751
	V. Khachatryan, M.B. Andorf, I.V. Bazarov, J.A. Crittenden, S.J. Levenson, J.M. Maxson, D.L. Rubin, J.P. Shanks, S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA W.F. Bergan BNL, Upton, New York, USA
	Funding: The authors thank the Center for Bright Beams, NSF award PHY-1549132; W.F.B. was supported by the NSF Graduate Research Fellowship Program under grant number DGE-1650441. A helical wiggler with parameter k_und=4.35 has been designed for the Optical Stochastic Cooling (OSC) experiment in the Cornell Electron Storage Ring (CESR). We consider four Halbach arrays, which dimensions are optimized to get the required helical field profile, as well as, to get the best Dynamic Aperture (DA) in simulations. The end poles are designed with different dimensions to minimize the first and second field integrals to avoid the need of additional correctors for the beam orbit. The design is adopted to minimize the risks for the magnet blocks demagnetization. To quantify the tolerances, we simulated the effects of different types of geometrical and magnetic field errors on the OSC damping rates. In addition, to understand the challenges for the construction, as well as, to validate the model field calculations, we prototyped a small two period version. The prototype field is compared to the model, and the results are presented in this work.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT066
About •	Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 14 June 2022
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THPOTK010	Development of a Short Period Superconducting Helical Undulator	2788
	A.G. Hinton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom J. Boehm, L. Cooper, B. Green, T. Hayler, P. Jeffery, C.P. Macwaters, B.J.S. Matthews STFC/RAL, Chilton, Didcot, Oxon, United Kingdom S. Milward DLS, Oxfordshire, United Kingdom B.J.A. Shepherd, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Superconducting technology provides the possibility to develop short period, small bore undulators that can generate much larger magnetic fields than alternative technologies. This may allow an XFEL with optimised superconducting undulators to cover a broader range of wavelengths than traditional undulators. At STFC, we have undertaken work to design and build a prototype superconducting helical undulator module with parameters suitable for use on a future XFEL facility. This work includes the design of an undulator with 13 mm period and 5 mm magnetic gap, as well as the supporting cryogenic and vacuum systems required for operation. We present here the updated design of the superconducting helical undulator that represents the results of prototyping work. Improved methods for manufacturing the undulator former and winding the superconducting wire have been developed. The measured mechanical tolerances and the impact on the field quality will be presented. The fields produced by prototype undulators will soon be measured using a Hall probe system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK010
About •	Received ※ 06 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 17 June 2022
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Paper

Title

Page

New Designs of Short-Period Undulators for Producing High-Brightness Radiation in Synchrotron Light Sources

1624

E.J. Wallén
LBNL, Berkeley, California, USA

We review modern state-of-the-art and new concepts of undulators planned for new generation light sources. Both superconducting and permanent-magnet-based insertion devices feature unique solutions to reach high precisely tunable fields in the period range of 10^-18 mm, 2-4 meters in length and with the ID gaps of less than 5 mm. The same quest for small gaps and shortest possible period length exists also for elliptically polarizing undulators. A review of new designs in Europe, Asia and Americas will be in the focus of this presentation.

Slides WEIYSP1 [21.171 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIYSP1

About •

Received ※ 15 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 07 July 2022

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THPOPT002

Beam Power Deposition on the Cryogenic Permanent Magnet Undulator

2556

L.R. Carver, C. Benabderrahmane, P. Brumund, N. Carmignani, J. Chavanne, G. Le Bec, R. Versteegen, S.M. White
ESRF, Grenoble, France

X-rays with high brilliance and low phase errors are generated in the Cryogenic Permanent Magnet Undulator (CPMU) currently in use at the ESRF. In the event of a failure of the cryogenic cooling the beam will continue to deposit power into the module, even when the undulator jaws are fully opened. This could lead to unacceptably high heating of the magnet blocks which could cause their demagnetisation. Impedance simulations were performed using IW2D and CST to compute the power deposited by the beam in both the closed and open jaw settings. This was followed by thermal simulations to compute the expected temperature rise. These results will help advise the operational procedure in the event of a cooling failure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT002

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Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022

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THPOPT032

SUNDAE2 at EuXFEL: A Test Stand to Characterize the Magnetic Field of Superconducting Undulators

2649

J.E. Baader, S. Abeghyan, S. Casalbuoni, D. La Civita, B. Marchetti, M. Yakopov, P. Ziolkowski
EuXFEL, Schenefeld, Germany
H.-J. Eckoldt, A. Hauberg, S. Lederer, L. Lilje, T. Wohlenberg, R. Zimmermann
DESY, Hamburg, Germany
A.W. Grau
KIT, Eggenstein-Leopoldshafen, Germany

European XFEL foresees a superconducting undulator (SCU) afterburner in the SASE2 hard X-ray beamline. It consists of six 5m-long undulator modules with a 5mm vacuum gap, where each module contains two 2m-long coils and one phase shifter. Prior to installation, the magnetic field must be mapped appropriately. Two magnetic measurement test stands named SUNDAE 1 and 2 (Superconducting UNDulAtor Experiment) are being developed at European XFEL. While SUNDAE1 will be a vertical test stand to measure SCU coils up to two meters with Hall probes in a liquid or superfluid helium bath, SUNDAE2 will measure the SCU coils assembled in the final cryostat. This contribution presents the development status of SUNDAE2 and its main requirements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT032

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Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022

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THPOPT050

Development and Construction of Cryogenic Permanent Magnet Undulators for ESRF-EBS

2712

C. Benabderrahmane, P. Brumund, J. Chavanne, D. Coulon, G. Le Bec, B. Ogier, R. Versteegen
ESRF, Grenoble, France

The ESRF Extremely Brilliant Source (ESRF-EBS) is on operation for Users since August 2020 after 20 months of shutdown. This first of a kind fourth generation high energy synchrotron is based on a Hybrid Multi-Bend Achromat lattice. The main goal of the ESRF-EBS is to reduce the horizontal emittance, which leads to a signifi-cant increase of the X-ray source brilliance. To cover the intensive demand of short period small gap undulators at ESRF-EBS, a new design for a 2 m Cryogenic Permanent Magnet Undulator (CPMU) has been developed. Six CPMUs will be installed in the next years; the first two CPMUs have been constructed and actually used on ID15 and ID16 beamline, the third one is under con-structing. An intensive refurbishment work has been done on the existing insertion devices to adapt them to the new accelerator which has shorter straight section and closer dipoles to the IDs than in the old one. This contribution will review the development, construc-tion and commissioning of the new CPMUs, and the refurbishment work done on the existing ones to adapt them to the new accelerator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT050

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Received ※ 02 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 18 June 2022

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THPOPT052

The Status of the In-Vacuum-APPLE II Undulator IVUE32 at HZB / BESSY II

2716

J. Bahrdt, J. Bakos, S. Gaebel, S. Gottschlich, S. Grimmer, S. Knaack, C. Kuhn, F. Laube, A. Meseck, C. Rethfeldt, E.C.M. Rial, A. Rogosch-Opolka, M. Scheer, P.I. Volz
HZB, Berlin, Germany

At BESSY II, two new beamlines for RIXS and for X-Ray-microscopy demand a short period variably polarizing undulator. For this purpose, the first in-vacuum APPLE undulator worldwide is under construction. The parameters are as follows: period length=32mm, magnetic length=2500mm, minimum gap=7mm. The design incorporates a force compensation scheme as proposed by two of the authors at the SRI2018. All precision parts of the drive chain are located in air. New transverse slides for the transversal slit adjustment have been developed and tested. Optical micrometers measure the gap and shift positions, similar to the system of the CPMU17 at BESSY II. They provide the signals for motor feedback loops. A new UHV-compatible soldering technique, as developed with industry, relaxes fabrication tolerances of magnets and magnet holders and simplifies the magnet assembly. A 10-period prototype has been setup for lifetime tests of the new magnetic keeper design. The paper describes first results of the prototype and other key-components and summarizes the status of the full-scale undulator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT052

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Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 22 June 2022

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THPOPT053

Goubau-Line Set Up for Bench Testing Impedance of IVU32 Components

2719

SUSPMF023

use link to see paper's listing under its alternate paper code

P.I. Volz, A. Meseck
HZB, Berlin, Germany
A. Meseck
KPH, Mainz, Germany

The worldwide first in-vacuum elliptical undulator, IVUE32, is being developed at Helmholtz-Zentrum Berlin. The 2.5 m long device with a period length of 3.2 cm and a minimum gap of about 7 mm is to be installed in the BESSY II storage ring. It will deliver radiation in the soft X-ray range to several beamlines. The proximity of the undulator structure to the electron beam makes the device susceptible to wakefield effects which can influence beam stability. A complete understanding of its impedance characteristics is required prior to installation and operation, as unforeseen heating of components could have catastrophic consequences. To understand and measure the IVU’s impedance characteristics a Goubau-Line test stand is being designed. A Goubau-line is a single wire transmission line for high frequency surface waves with a transverse electric field resembling that of a charged particle beam out to a certain radial distance. A concept optimized for bench testing IVUE32-components will be discussed, microwave simulations will be presented together with first measurements from a test stand prototype.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT053

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022

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THPOPT058

Status and Powering Test Results of HTS Undulator Coils at 77 K for Compact FEL Designs

2726

SUSPMF024

use link to see paper's listing under its alternate paper code

S.C. Richter, A. Bernhard, A.-S. Müller
KIT, Karlsruhe, Germany
A. Ballarino, T.H. Nes, S.C. Richter, D. Schoerling
CERN, Meyrin, Switzerland

Funding: This work has been supported by the Wolfgang Gentner Program of the German Federal Ministry of Education and Research (grant no. 05E18CHA).
The production of low emittance positron beams for future linear and circular lepton colliders, like CLIC or FCC-ee, requires high-field damping wigglers. Just as compact free-electron lasers (FELs) require high-field but as well short-period undulators to emit high energetic, coherent photons. Using high-temperature superconductors (HTS) in the form of coated ReBCO tape superconductors allows higher magnetic field amplitudes at 4 K and larger operating margins as compared to low-temperature superconductors, like Nb-Ti. This contribution discusses the development work on superconducting vertical racetrack (VR) undulator coils, wound from coated ReBCO tape superconductors. The presented VR coils were modularly designed with a period length of 13 mm. Powering tests in liquid nitrogen of multiple vertical racetrack coils were performed at CERN. The results from the measurements are presented for three VR coils and compared with electromagnetic simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT058

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Received ※ 17 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 21 June 2022

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THPOPT060

Tolerance Study on the Geometrical Errors for a Planar Superconducting Undulator

2734

V. Grattoni, S. Casalbuoni, B. Marchetti
EuXFEL, Schenefeld, Germany

At the European XFEL, a superconducting afterburner is considered for the SASE2 hard X-ray beamline. It will consist of six undulator modules. Within each module, two superconducting undulators (SCU) 2 m long are present. Such an afterburner will enable photon energies above 30 keV. A high field quality of the SCU is crucial to guarantee the quality of the electron beam trajectory, which is directly related to the spectral quality of the emitted free-electron laser (FEL) radiation. Therefore, the effects of the SCU’s mechanical imperfections on the resultant magnetic field have to be carefully characterized. In this contribution, we present possible mechanical errors affecting the undulator structure, and we perform an analytical study aimed at determining the tolerances on these errors for our SCUs.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT060

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Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 27 June 2022

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THPOPT061

European XFEL Undulators - Status and Plans

2737

S. Casalbuoni, S. Abeghyan, J.E. Baader, U. Englisch, V. Grattoni, S. Karabekyan, B. Marchetti, H. Sinn, F. Wolff-Fabris, M. Yakopov, P. Ziolkowski
EuXFEL, Schenefeld, Germany

European XFEL has three undulator lines based on permanent magnet technology: two for hard and one for soft X-rays. The planar undulators can be tuned to cover the acceptance in terms of photon beam energy of the respective photon beamlines: 3.6-25 keV (SASE1/2) and 0.25-3 keV (SASE3) by changing the electron energy range between 11.5 GeV and 17.5 GeV and/or the undulator gap. In order to obtain different polarization modes, as required by the soft X-ray beamlines, a helical afterburner consisting of four APPLE X undulators designed by PSI has been installed at the downstream end of the present SASE3 undulator system. The European XFEL plans to develop the technology of superconducting undulators, which is of strategic importance for the facility upgrade. In order to extend the energy range above 30 keV a superconducting undulator afterburner is foreseen to be installed at the end of SASE2. This contribution presents the current status and the planned upgrades of the undulator lines at European XFEL.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT061

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Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022

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THPOPT063

Design of Scilab Xcos Simulation Model for Pulsed Wire Method Data Analyses

2741

H. Jeevakhan
NITTTR, Bhopal, India
S.M. Khan, G. Mishra
Devi Ahilya University, Indore, India

Pulsed wire method (PWM)is used for undulator characterisation. Scilab Xcos simulation model is designed for the analyses of data obtained by PWM. The data obtained from PWM is given as input to the model and its output gives the magnetic field of the undulator. Scilab Xcos model can also be utilized for determining the phase error of the undulator.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT063

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Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 09 July 2022

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THPOPT064

Hall Probe Magnetic Measurement of 50 mm Period PPM Undulator

2744

SUSPMF025

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S.M. Khan, G. Mishra
Devi Ahilya University, Indore, India
M. Gehlot
MAX IV Laboratory, Lund University, Lund, Sweden
H. Jeevakhan
NITTTR, Bhopal, India

In this paper, we present the latest upgradation of Hall Probe magnetic measurement system. The Hall Probe measurement system is upgraded with position measuring detectors and 3D F.W. Bell Teslameter. The field integrals and the phase errors are calculated with a new user friendly MATLAB code. The integrated multipoles both normal and skew components are measured and discussed in the paper. The proposed activities on 300 mm length prototype asymmetric undulator and 50 mm quasi period, six period length at Laser Instrumentation and Insertion Device Application laboratory of Devi Ahilya Vishwa Vidyalaya (DAVV), Indore, India has been discussed and design components are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT064

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Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 22 June 2022

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THPOPT066

Helical Wiggler Design for Optical Stochastic Cooling at CESR

2751

V. Khachatryan, M.B. Andorf, I.V. Bazarov, J.A. Crittenden, S.J. Levenson, J.M. Maxson, D.L. Rubin, J.P. Shanks, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
W.F. Bergan
BNL, Upton, New York, USA

Funding: The authors thank the Center for Bright Beams, NSF award PHY-1549132; W.F.B. was supported by the NSF Graduate Research Fellowship Program under grant number DGE-1650441.
A helical wiggler with parameter k_und=4.35 has been designed for the Optical Stochastic Cooling (OSC) experiment in the Cornell Electron Storage Ring (CESR). We consider four Halbach arrays, which dimensions are optimized to get the required helical field profile, as well as, to get the best Dynamic Aperture (DA) in simulations. The end poles are designed with different dimensions to minimize the first and second field integrals to avoid the need of additional correctors for the beam orbit. The design is adopted to minimize the risks for the magnet blocks demagnetization. To quantify the tolerances, we simulated the effects of different types of geometrical and magnetic field errors on the OSC damping rates. In addition, to understand the challenges for the construction, as well as, to validate the model field calculations, we prototyped a small two period version. The prototype field is compared to the model, and the results are presented in this work.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT066

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Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 14 June 2022

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THPOTK010

Development of a Short Period Superconducting Helical Undulator

2788

A.G. Hinton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
J. Boehm, L. Cooper, B. Green, T. Hayler, P. Jeffery, C.P. Macwaters, B.J.S. Matthews
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
S. Milward
DLS, Oxfordshire, United Kingdom
B.J.A. Shepherd, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Superconducting technology provides the possibility to develop short period, small bore undulators that can generate much larger magnetic fields than alternative technologies. This may allow an XFEL with optimised superconducting undulators to cover a broader range of wavelengths than traditional undulators. At STFC, we have undertaken work to design and build a prototype superconducting helical undulator module with parameters suitable for use on a future XFEL facility. This work includes the design of an undulator with 13 mm period and 5 mm magnetic gap, as well as the supporting cryogenic and vacuum systems required for operation. We present here the updated design of the superconducting helical undulator that represents the results of prototyping work. Improved methods for manufacturing the undulator former and winding the superconducting wire have been developed. The measured mechanical tolerances and the impact on the field quality will be presented. The fields produced by prototype undulators will soon be measured using a Hall probe system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK010

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Received ※ 06 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 17 June 2022

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