Superconducting quadrupole magnets for the interaction regions of the Large
Hadron Collider are being developed by the US-LHC Accelerator Project. The
se 70 mm bore quadrupole magnets are intended to operate in superfluid heli
um at 1.9 K with a nominal field gradient of 215 T/m. A series of 2 m model
magnets are being built and tested at Fermilab to optimize design and cons
truction parameters. Measurements of the field quality of the model magnets
tested to date and comparisons with the required field quality are reporte
d in this paper.