Magnetic field measurements of the main injector sextupole magnets

The Fermilab Main Injector (MI) will accelerate (decelerate) protons and anti-protons from 8.9 GeV/c to 150 GeV/c (150 GeV/c to 8.9 GeV/c). To achieve high intensity stable beam in the MI throughout the acceleration or deceleration mode, two families of chromaticity compensation sextupole magnets are planned. The operating schemes for the chromaticity compensation systems will be different for the two modes because of the hysteresis of the sextupole magnets and the changed sign of the sextupole field component from beam tube eddy currents in the dipoles. Hence we have carried out detailed magnetic field measurements on some sextupole magnets. Here we present the results of the measurements and their implications on the acceleration and the deceleration cycles of the MI.