The damage mechanisms and limits of superconducting accelerator magnets caused by the impact of high-intensity particle beams have been the subject of extensive studies at CERN in the recent years. Recently, an experiment with dedicated racetrack coils made of Nb-Ti and Nb3Sn strands was performed in CERN’s HiRadMat facility. In this paper, the design and construction of the sample coils as well as the results of their qualification before the beam impact are described. Furthermore, the experimental setup is discussed. Finally, the measurements during the beam experiment such as the beam-based alignment, the observations during the impact of 440 GeV protons on the sample coils and the obtained hotspots and temperature gradients are presented.

The far-infrared linac and test experiment (FLUTE) serves as an accelerator test facility for a variety of accelerator physics studies. FLUTE is foreseen to provide coherent radiation in ultra-short, very intense light pulses in the terahertz (THz) and far-infrared spectral range. A superconducting undulator in the accelerator structure after bunch compression offers the possibility to generate high-energy, pulsed radiation between 4 THz and 12 THz corresponding to photon energies between 16.5 meV and 50 meV. This energy range, for instance, is of high interest for interaction and reaction studies of liquids, especially in water, and thus for materials and medical research. In this contribution we describe the specific design parameters and the general layout of the THz superconducting undulator to reach the envisioned scientific goals.

n recent years the interest in high intensity, short-pulse coherent THz radi- ation for non-linear experimental research and applications grew with upcoming high intensity lasers. In contrast to lasers, accelerators provide free electrons for which emission properties can be tailored to the demand at typically much higher repetition rates than high-intensity lasers can provide. Efforts are ongo- ing to augment short-bunch accelerators such as the European XFEL with THz radiation sources such as undulators. At the far-infrared linac and test experiment (FLUTE) at KIT, we can facil- itate experiments to investigate coherent THz radiation from different sources and provide short electron bunches. As an additional THz source, a supercon- ducting undulator can be inserted and investigated. In this contribution, we evaluate the opportunities of this THz undulator at FLUTE for linear accelerators and FELs in terms of photon science and beam dynamics.

An experiment to study damage caused by the impact of 440 GeV/c protons on sample superconducting racetrack coils made from NbTi and Nb3Sn strands was recently carried out at CERN's HiRadMat facility. This paper reports on the detailed Monte Carlo simulations performed with FLUKA and Geant4 to evaluate the energy deposition of the 440 GeV/c proton beam on the sample coils positioned in the experimental setup. using the measured beam parameters during the experiment. The measured hotspot temperatures and temperature gradients reached in the sample coils are presented and compared with the simulations. In addition, comparisons between the simulation results from FLUKA and Geant4 are discussed in detail.

The damage mechanisms and limits of superconducting accelerator magnets caused by the impact of high-intensity particle beams have been the subject of extensive studies at CERN in the recent years. Recently, an experiment with dedicated racetrack coils made of Nb-Ti and Nb3Sn strands was performed in CERN’s HiRadMat facility. In this paper, the design and construction of the sample coils as well as the results of their qualification before the beam impact are described. Furthermore, the experimental setup is discussed. Finally, the measurements during the beam experiment such as the beam-based alignment, the observations during the impact of 440 GeV protons on the sample coils and the obtained hotspots and temperature gradients are presented.

One of the key issues in the technology of superconductors is the protection against quenches. When designing a superconductor as a magnet, a coil or even current leads, the design should be made such that the superconductor withstands all operational conditions as fast discharges, pulsed loads or even rapid transient background fields. Computational modeling of pulsed-current characterization in a self-field NbTi racetrack sample coil has been performed using the finite element modelling software Opera as a step towards understanding the thermal and electromagnetic processes during a quench. The pulse was modelled to be generated by discharging a capacitor into an RLC circuit, which includes the NbTi racetrack coil as the sample under test. The coil was driven to the resistive state and the quench occurred by applying the pulse with a peak value exceeding the critical current of the sample coil. This contribution presents the results obtained from investigating a pulsed NbTi coil in a model based on an electromagnetic analysis. In addition, a comparison to the theoretical expectations derived for the damped oscillations in the pulse-driving circuit is given. Finally, the results from a coupled analysis, where both thermal and electromagnetic properties are being considered, within a quench multi-physics study are presented.

Superconducting (SC) undulators composed of high-temperature superconducting (HTS) tapes, which can be applied to compact light sources such as a table-top free-electron laser, are a part of research and development projects at Karlsruhe Institute of Technology (KIT). In order to minimize the beam heat loads in a cryostat including the compact SC planar undulator, a vacuum chamber (liner) positioned in the undulator gap is considered. In this study, we discuss the preliminary cryostat design based on a simple cooling concept with a cryocooler and report thermal and mechanical simulation results with the liner at cryogenic temperature.

A 1.6 m long 16 mm period superconducting undulator (SCU16) has been installed and commissioned at the Australian Synchrotron. The SCU16, developed by Bilfinger Noell GmbH, is based on the SCU20 currently operating at at KIT. The SCU16 is conduction cooled with a maximum on axis field of 1.084 T and a fixed effective vacuum gap of 5.5 mm. The design and performance of the longest superconducting undulator at a light source will be presented.