MEASUREMENTS OF QUENCH VELOCITY IN ADIABATIC NBTI AND NBSN COILS - COMPARISON BETWEEN THEORY AND EXPERIMENTS IN SMALL MODEL COILS AND LARGEMAGNETS

We investigated the quench propagation velocity in small epoxy impregn ated NbTi and NbSn windings. Eventually we took data directly on a lar ge epoxy impregnated NbTi magnet (phi(in) = 640 mm, B(max) = 8 T), whe re quenches were induced at 4,5 and 6 teslas and voltage across subsec tions were recorded at constant current by delaying the dumping system intervention. Results show a discrepancy with the predictions given b y the usual formulas for turn to turn propagation, while good agreemen t was found for longitudinal one. In the paper the cable and magnet ch aracteristics are reported in detail as well as some measured curves, such as to be compared with results of other researchers.