The Main Injector chromaticity correction sextupole magnets: measurements and operating schemes

The Fermilab Main Injector (FMI) is a high intensity proton synchrotron which will be used to accelerate protons and antiprotons from 8.9 GeV to 150 GeV. The natural chromaticities of the machine for the horizontal and the vertical planes are -33.6 and -33.9 respectively. The Δp/p of the beam at injection energy of 8.9 GeV is about 0.002. The chromaticity requirements of the FMI are primarily decided by the Δp/p=0.002 of the beam at injection. This limits the final chromaticity of the FMI to be ±5 units. To correct the chromaticity in the FMI, two families of sextupole magnets will be installed in the lattice, one for each plane. A sextupole magnet suitable for the FMI needs has been designed and are being built. New chromaticity compensation schemes have been worked out in the light of recently proposed faster acceleration ramps. On a R/D sextupole magnet, the low current measurements have been carried out to determine the electrical properties. Also with a Morgan coil, measurements have been performed to determine the higher ordered multipole components up to 18-poles. An overview of these results are presented here