Results from Heater-Induced Quenches of a 4.5 m Two-in-One Superconducting R&D Dipole for the SSC

Quench studies were performed using a 4.5 m long SSC R&D dipole to determine the temperature rise during a quench by measuring the resistance of the conductor cable in the immediate vicinity of the quench. The 2-in-1 magnet was wound with improved "high homogeneity" NbTi conductor in a 2-layer cosine ¿ coil configuration of 3.2 cm inner diameter with each layer powered separately to simulate graded conductor. Twelve pairs of voltage taps were installed at various locations in the coils around one bore of the magnet. "Spot" heaters were placed between the voltage taps of 8 of these pairs to initiate magnet quenches. The resistance of the conductor was obtained from observations of the current and voltage during a magnet quench. The temperature of the conductor was then determined by comparing its resistance to an R vs T curve measured independently for the conductor. The quantity ¿I2dt is presented as a function of current and location, and the maximum conductor temperature is shown as a function of ¿I2dt and location. Measured longitudinal and azimuthal quench propagation velocities are also presented.