Precision quadrupole magnets for the HERA luminosity upgrade

The Efremov Institute and DESY have designed in collaboration high performance normal conducting quadrupole magnets for the HERA luminosity upgrade. One of the most ambitious is the type GA. It has a length of 3.85 m, a pole radius of 35 mm and must provide a maximum gradient of 26 T/m. The required field nonlinearity is /spl Delta/B/B/spl les/3/spl times/10/sup -4/ at a reference radius of 25 mm. A special feature is a clearance between the coil and the iron yoke that holds the separate electron beam pipe. This contribution deals with the production of the magnets and the results of the mechanical as well as magnetic measurements in comparison with the design values.