Experimental study of the quench properties of epoxy impregnated coupled coils wound with NbTi and NbSn

The authors have carried out an investigation on the quench properties of small coupled adiabatic coils, each one consisting of an outer NbTi shell and an inner Nb₃Sn shell. The outer diameter is less than 100 mm and the maximum central magnetic field is in the 10 T range. The propagation of heater induced quenches was investigated by recording the voltage across voltage taps soldered to the coils. The NbTi and Nb₃Sn coils can be electrically connected or can be energized independently and separately protected using independent dumping resistors. The authors report the predictions given by a computer program for multicoil systems. The computer simulations are compared with the measured values, and the corrections to the usual formulae for the propagation velocity, needed to fit the experiments, are given