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Only since few years it has been demonstrated experimentally that NbTi based superconducting undulators (SCUs) have a higher peak field on axis for the same gap and period length in operation with electron beam with respect to permanent magnet undulators (even the ones in vacuum and cooled to cryogenic temperatures). Another advantage of NbTi based SCUs with respect to permanent magnet devices is radiation hardness, widely demonstrated for NbTi magnets, which is and will become an increasingly important issue with the small gaps in the newest machines as round beam storage rings and FELs. Moreover, SCU technology allows switching of the period length by changing the current direction in one of separately powered subset of winding packages of the superconducting coils. This feature further broadens the energy range of the emitted photons, required by the different beamlines. To this end 0.5 m long superconducting undulator coils with switchable period length between 17 mm and 34 mm have been developed. In this contribution we describe the design and report on the quench tests, as well as on the magnetic field measurements., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Within the collaborative effort between KIT and Bilfinger Noell GmbH the development of a full scale superconducting undulator with 20 mm period length (SCU20) has been completed. This device addresses the reliability and reproducibility aspects of the manufacturing process, allowing for the status of a commercial product. The conduction cooled 1.5 m long coils were characterized in the KIT horizontal test facility CASPER II and later assembled in the final cryostat. The system was extensively tested in the final configuration before installation in the KIT storage ring KARA (Karlsruhe Research Accelerator) to be the source of the NANO beamline in December 2017. Here we present the performance of the device., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Several photon beamlines in different synchrotron make use of undulators with switchable period length, which offer a larger tunability of the emitted photons energy. Superconducting technology allows switching the period length by changing the sign of the current in separately powered subset of windings. We present here the design and tests performed in liquid helium of switchable period length superconducting undulator coils performing period doubling from 17 mm to 34 mm., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The Institute for Beam Physics and Technology (IBPT) of the Karlsruhe Institute of Technology (KIT), and the company Babcock Noell GmbH (BNG) are running an R&D program on superconducting undulators (SCUs). The collaboration is working on a SCU with 20 mm period length (SCU20) for ANKA, the test facility and synchrotron radiation source, run by the IBPT. The 1.5 m long undulator coils have been tested in a conduction-cooled environment. This contribution describes the training, the stability and the thermal behavior of the coils., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

At the synchrotron ANKA (ANgstrom source KArlsruhe) we pursue a research and development program on superconducting undulators (SCUs). This technology is of interest to improve the spectral characteristics of the emitted photons in third and fourth generation light sources. We present here the results obtained within the ongoing collaboration with the industrial partner Babcock Noell GmbH (BNG) on NbTi conduction cooled planar devices. Investigations on the application of alternative superconductors as well as a summary of the achievements reached to precisely characterize the magnetic field properties of SCUs and to measure the beam heat load to a cold bore are also described., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

Superconducting insertion devices (IDs) can reach, for the same gap and period length a higher field strength compared to permanent magnet IDs. Their performance depends strongly on the magnetic field quality. While the magnetic measurements technology of permanent magnet based IDs made significant progress during the last years, for superconducting IDs similar major developments are necessary. As a part of our R&D program for superconducting insertion devices at the ANKA synchrotron light source a measurement setup for conduction cooled superconducting coils with a maximum length of 2 m was built and commissioned. In the CASPER II (Characterization Setup for Phase Error Reduction) facility the magnet coils can be trained and tested for maximum current and field quality, including the local field distribution as well as the first and second field integrals. In this paper we shortly describe the CASPER II setup and focus on the capability of this measurement device by presenting the results of a superconducting undulator mockup with a period length of 20 mm., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

The knowledge of the heat intake from the electron beam is essential to design the cryogenic layout of superconducting insertion devices. With the aim of measuring the beam heat load to a cold bore and understanding the responsible mechanisms, a cold vacuum chamber for diagnostics (COLDDIAG) has been built. The instrumentation comprises temperature sensors, pressure gauges, mass spectrometers and retarding field analyzers, which allow to study the beam heat load and the influence of the cryosorbed gas layer. COLDDIAG was installed in the storage ring of the Diamond Light Source from September 2012 to August 2013. During this time measurements were performed for a wide range of machine conditions, employing the various measuring capabilities of the device. Here we report on the analysis of the measured beam heat load, pressure and gas content, as well as the low energy charged particle flux and spectrum as a function of the electron beam parameters., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

The Institute for Beam Physics and Technology (IBPT) at the Karlsruhe Institute of Technology (KIT) and the industrial partner Babcock Noell GmbH (BNG) are col-laborating since 2007 on the development of superconducting undulators both for ANKA and low emittance light sources. The first full length device with 15 mm period length has been successfully tested in the ANKA storage ring for one year*. The next superconducting undulator has 20 mm period length (SCU20) and is also planned to be installed in the accelerator test facility and synchrotron light source ANKA. The SCU20 1.5 m long coils have been characterized in a conduction cooled horizontal test facility developed at KIT IBPT. Here we present the local magnetic field and field integral measurements, as well as their analysis including the expected photon spectrum., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark