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Superconducting Undulators (SCUs) can produce higher photon flux and cover a wider photon energy range compared to permanent magnet undulators (PMUs) with the same vacuum gap and period length. To build the know-how to implement superconducting undulators for future upgrades of the European XFEL facility, two magnetic measurement test stands named SUNDAE 1 and 2 (Superconducting UNDulAtor Experiment) are being developed. SUNDAE1 will facilitate research and development on magnet design thanks to the possibility of training new SCU coils and characterizing their magnetic field. The experimental setup will allow the characterization of magnets up to 2m in length. These magnets will be immersed in a Helium bath at 2K or 4K temperature. In this article, we describe the experimental setup and highlight its expected performances., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

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., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

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., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

[Ebook] 13th International Particle Accelerator Conference : June 12-17, 2022, Impact Forum, Muangthong Thani, Bangkok, Thailand : conference proceedings / Chanwattana, Thakonwat , [Geneva] : JACoW Publishing, July 2022, 13th International Particle Accelerator Conference, IPAC'22, Bangkok, Thailand, 12 Jun 2022 - 17 Jun 2022; Geneva, Switzerland : JACoW Publishing 1029-1032 (2022). doi:10.18429/JACOW-IPAC2022-TUPOPT014, The undulator systems at the European XFEL consist of two hard X-ray systems, SASE1 and SASE2, and one soft X-ray system, SASE3. All three systems are equipped with planar undulators using permanent neodymium magnets. These systems allow the generation of linearly polarized radiation in the horizontal plane. In order to generate variable polarization radiation in the soft X-ray range, an afterburner is currently being implemented behind the SASE3 planar undulator system. It consists of four APPLE-X helical undulators. The project, called SASE 3 Variable Polarization, is close to being put into operation. All four helical undulators have been installed in the tunnel during the 2021-2022 winter shutdown. This paper describes the status of the project and the steps toward its commissioning. It also presents lessons learned during the implementation of the project., Published by JACoW Publishing, Geneva, Switzerland

Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil 12th International Particle Accelerator Conference, IPAC���21, Campinas, SP, Brazil, 24 May 2021 - 28 May 2021; 3 pp. (2021). doi:10.18429/JACOW-IPAC2021-TUPAB122, At the European XFEL, two undulator systems for hard and one for soft X-rays have been successfully put into operation. The SASE3 soft X-ray undulator system generates linearly polarized radiation in the horizontal plane. One of the requirements for extending the radiation characteristics is the ability to obtain different polarization modes. These include both right and left circular, elliptical polarization, or linear polarization at an arbitrary angle. For this purpose, a system consisting of four APPLE X helical undulators developed at the Paul Scherrer Institute (PSI) is used. This paper presents the design parameters of the SASE3 undulator system after modifying it with the helical afterburner. It also describes the methods and the design solutions different from those used at PSI. The status and schedule of the project are introduced.

The correct K value of an undulator is an important parameter to achieve lasing conditions at free electron lasers. The accuracy of the installation of the undulator in the tunnel is limited by the accuracy of the instruments used in surveying. Moreover, the position of the electron beam also varies depending on its alignment. Another source of misalignment is ground movement and the resulting change in the position of the tunnel. All this can lead to misalignment of the electron beam position relative to the center of the undulator gap up to several hundred microns. That, in turn, will lead to a deviation of the ΔK/K parameter several times higher than the tolerance requirement. An automated method of aligning the middle plane of the undulator, using a K-monochromator, was developed and used at European XFEL. Details of the method are described in this article. The results of the K value measurements are discussed., Proceedings of the 17th International Conference on Accelerator and Large Experimental Physics Control Systems, ICALEPCS2019, New York, NY, USA

To eliminate the impact of radiation shower on the incremental encoder readout and provide a better dynamic movement the upgrade of all 88 phase shifters of the European XFEL have been successfully done without interruption of the operation schedule. The implementation steps, as well as the results of the hardware and software tests made in the laboratory, are presented. The sensitivity of the Renishaw RGH22O15D00A encoder to the radiation shower was measured in the SASE3 undulator system, and the results are presented., Proceedings of the 17th International Conference on Accelerator and Large Experimental Physics Control Systems, ICALEPCS2019, New York, NY, USA

This article describes in detail the steps of hardware installation and commissioning of components for undulator systems at European XFEL. In general, the work can be divided into 3 different steps: installation, alignment, and commissioning. During installation step, the following main components were rolled into the tunnel: - undulators with the control cabinets, intersection control cabinets, phase shifters, quadrupole movers, correction coils. They have been mounted according to the designed positions. Then all mentioned components have been aligned according to the specifications. Finally, the cabling has been done and basic tests were performed. As part of the commissioning, the calibration of the temperature sensors, as well as the measurements of the quadrupole mover travel distance has been done in the tunnel. Afterwards, the undulator limit switches and hard stops were adjusted to secure the vacuum chamber by closing the undulator gap up to 10mm. Eventually, the system was handed over to the global control system in order to perform all functional tests. The main focus is given to the components which are controlled or monitored by the undulator local control system [1]., Proceedings of the 16th Int. Conf. on Accelerator and Large Experimental Control Systems, ICALEPCS2017, Barcelona, Spain

The European XFEL is a fourth-generation light source, which will start the operation in spring 2017. Three undulator systems - SASE 1, SASE 2 and SASE 3 - will be used to produce photon beams. For operation of all undulator systems, a total amount of 91 undulators have been produced and commissioned. SASE 1 and SASE 3 undulator systems, consisting of total 56 undulator cells, have been installed and prepared for the operation in the tunnel in spring and summer 2016. SASE 2 will be installed by the end of 2016. This paper describes the commissioning process of the whole undulator control system and reports about the experience gained over the entire duration of undulator control system commissioning., Proceedings of the 11st Int. Workshop on Personal Computers and Particle Accelerator Controls, PCaPAC2016, Campinas, Brazil

To ensure self-amplified spontaneous emission process an undulator used for this must not deflect the electron beam from its orbit. The possible deflection of the electron beam, introduced by undulator, must be corrected by means of two air coils. These air coils, which are installed from both sides of the undulator, must eliminate not only the deflection angle, but also the displacement between electron beam trajectory and the orbit. For European XFEL 182 air coils are necessary. To minimize the measurement time an automated procedure has been developed and implemented. This paper describes the measurement setup, technical implementation method and automation procedure., Proceedings of the 11st Int. Workshop on Personal Computers and Particle Accelerator Controls, PCaPAC2016, Campinas, Brazil

The European XFEL is a 3.4km long X-ray Free Electron Laser in the final construction and commissioning phase in Hamburg. It will produce 27000 bunches per second at 17.5GeV. Early 2015 a first electron beam was produced in the RF-photo-injector and the commissioning of consecutive sections is following during this and next year. The huge number and variety of devices for the accelerator, beam line, experiment, cryogenic and facility systems pose a challenging control task. Multiple systems, including industrial solutions, must be interfaced to each other. The high number of bunches requires a tight time synchronization (down to picoseconds) and high performance data acquisition systems. Fast feedbacks from front-ends, the DAQs and online analysis system with a seamless integration of controls are essential for the accelerator and the initially 6 experimental end stations. It turns out that the European XFEL will be the first installation exceeding 2500 FPGA components in the MicroTCA form factor and will run one of the largest PROFIBUS networks. Many subsystem prototypes are already successfully in operation. An overview and status of the XFEL control system will be given., Proceedings of the 15th Int. Conf. on Accelerator and Large Experimental Physics Control Systems, ICALEPCS2015, Melbourne, Australia

Proceedings of ICALEPCS 2015 15th International Conference on Accelerator and Large Experimental Physics Control Systems, ICALEPCS 2015, Melbourne, Australia, 17 Oct 2015 - 23 Oct 2015 ; MOA3O02(2015)., The European XFEL is a 3.4 km long X-ray Free Electron Laser in the final construction and commissioning phase in Hamburg. It will produce 27000 bunches per second at 17.5 GeV. Early 2015 a first electron beam was produced in the RF-photo-injector and the commissioning of consecutive sections will follow during this and next year. The huge number and variety of devices for the accelerator, beam line, experiment, cryogenic and facility systems pose a challenging control task. Multiple systems, including industrial solutions, must be interfaced to each other. The large number of bunches requires a tight time synchronization (down to picoseconds) and high performance data acquisition systems. Fast feedbacks from front-ends, the DAQs and online analysis system with a seamless integration of controls are essential for the accelerator and the initially 6 experimental end stations. It turns out that the European XFEL will be the first installation exceeding 2500 FPGA components in the MicroTCA form factor and will run one of the largest PROFIBUS networks. Many subsystem prototypes are already successfully in operation. An overview and status of the XFEL control system will begiven.