Steering Field Quality in the Main Dipole Magnets of the Large Hadron Collider

Abstract

More than 10% of the collared coils of the main LHC dipoles have been produced. In this paper, we compare the measured field quality to beam dynamics targets using correlations to measurements at 1.9 K. The present status of field quality is given and corrective actions carried out to center field quality on optimal values are presented. Differences among the three manufacturers are analyzed, and the main results that concern correlation between cold and warm measurements are outlined. Present trends in the production and open points are discussed.