Magnetic field measurements of a 1-m long model quadrupole magnet for the LHC interaction region

The magnetic field measurements of the first l-m long model magnet for the LHC interaction region were performed at 1.9 K. The measured field gradient of the magnet was 227.7 T/m at 7200 A. The multipole fields as a function of axial position and magnet current were measured. The major higher multipole at the magnet center was the sextupole and the ratio to the quadrupole field was 1.4/spl times/10/sup -4/ at 7200 A and at a reference radius of 17 mm.