Investigations on NbTi superconducting racetrack coils under pulsed-current excitations

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

Energy deposition simulations for a damage experiment with superconducting sample coils

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\u27s 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