Measurement of time dependent fields in high gradient superconducting quadrupoles for the Tevatron

Magnetic field measurements have been performed on prototype and production magnets from two high-gradient superconducting quadrupole designs. One design is a double-shell quadrupole with 36-strand Rutherford cable. The other design is a single-shell quadrupole with five individually insulated monolithic strands connected in series. These magnets have similar bore diameters and cable dimensions. However, there are significant differences between the two designs, as well as differences between prototype and production magnets within each design, with regard to Cu-to-superconductor ratio, filament diameters, and filament-spacing-to-strand-diameter ratio. The time dependence at fixed currents of the measured magnetic field is discussed