AC magnetic measurements of the ALS booster dipole engineering model magnet

Ten-Hertz sine wave and two-Hertz sawtooth AC magnetic measurements of the curved Advanced Light Source (ALS) booster dipole engineering model magnet have been accomplished. Long curved coils were utilized to measure the integral transfer function and uniformity. Point coils and a Hall probe were used to measure magnetic induction and its uniformity. The data were logged and processed by a Tektronix 11401 digital oscilloscope. The dependence of the effective length on the field was determined from the ratio of the integral coil signals to the point coil signals. Quadrupole and sextupole harmonics were derived from the point and integral uniformity measurements. The magnetic length and field uniformity values obtained demonstrate that the magnet design meets the specifications and qualify it for production