MEASUREMENT OF QUENCH BACK BEHAVIOR ON THE NORMAL ZONE PROPAGATION VELOCITY IN A CICC

The normal zone propagation velocity in a cable-in-conduit conductor (CICC) has been experimentally investigated. The CICC used for this experiment consists of eighteen NbTi/Cu composite strands inserted in a stainless steel conduit with 26 m length. The measurement of the propagation velocity of the normal front was carried out by observing the appearance of the resistive voltage on each of taps attached to the conductor. In this experiment the quench back behavior that the propagation velocity is suddenly increased, was observed, which has been predicted from numerical simulations by C. Luongo et al. The behavior was influenced by the initial helium pressure within the conduit and was easy to occur at low pressure.