An automated measuring system for the antiproton accumulator magnets

The diversity of magnet measurement and shimming requirements, together with the short construction period of the Antiproton Accumulator, led to the choice of an automatic measuring system for the 24 quadrupoles and 12 dipoles of the AA ring. A CAMAC based microcomputer was used for control, storage and some local reduction of measurements. In order to accomplish the extensive shimming programme the need to make continuous measurements, with in-flight acquisition of coil position and voltage, was met by the use of fast electronics and processor code subroutines for the computer acquisition of measured values. Relative position errors were less than 0.1 mm and relative field or gradient errors were 3 parts in 10⁴.