We studied quench protection criteria for high transition-temperature superconducting (FITS) model magnet that was fabricated to demonstrate the possibility of FITS-based gantry. We aim to evaluate the frequency of "flux jump" events of this model magnet with varying operating temperature (T-OP), which was observed during previous excitation tests. Therefore, we investigated the operation margin for various T(OP)s based on simulation and developed the quench protection system of this model magnet. A short sample of rare-earth barium copper oxide coated conductor, which was used for winding the FITS coil, was prepared and its current-voltage characteristics were measured between the temperature range of 40-83 K. The obtained results were then implemented to our stand-alone simulation to perform the quench study. The maximum allowed elapsed time after the magnet quench was investigated for different operating currents and T(OP)s by varying the detection voltages (V(det)s). Then, a protection circuit was integrated into our simulation to optimize the size of dump resistor (R-dump) and V-det. Finally, it was observed that R-dump must not be above 4 Omega and V-det must be kept below 50 mV to protect the HTS model magnet.

The conduction-cooled superconducting magnets are now widely used in various applications due to their minimum usage of helium. In the accelerator science, they also play an increasingly important role in particle detector solenoids because they can minimize the materials needed for the magnet such that they can be more transparent against irradiated particles. For the same reason they are currently used in high radiation environments because they can reduce the heat load from the irradiation. However, the hadronic reactions, such as neutron or proton irradiation, can create degradation on the thermal conductivity of pure aluminum which is used as a cooling path. It leads to a poor cooling condition of the magnets. In Japan, there are two conduction-cooled superconducting magnets for muon production; one is already constructed and under operation, the other is now under construction. This paper briefly reports the influence of the irradiation on those magnets and discusses the possibilities of HTS based conduction-cooled magnets under high irradiation environments.