EXPERIMENTAL-STUDY OF THE QUENCH PROPERTIES OF EPOXY IMPREGNATED COUPLED COILS WOUND WITH NBTI AND NBSN

We have carried out an investigation on the quench properties of small coupled adiabatic coils, each one consisting of an outer NbTi shell and of an inner Nb3Sn shell. The outer diameter is less than 100 mm and the maximum central magnetic field is in the 10 Tesla 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 paper starts with a description of the theoretical approach to the problem, of the coils and the experimental equipment. Then we report the predictions given by a computer program for multicoil systems that we developed in our laboratory. The computer simulations are compared with the measured values and the corrections to the usual formulae for the propagation velocity, needed in order to fit the experiments, are given.