LBL program of 1 meter long, 50 mm diameter bore, dipoles with fields greater than 8 tesla

Model dipole superconducting magnets with central fields above 8 tesla are being developed for future multi-TeV colliding beam accelerators. The first three models are 1 meter long, have nominal 50 mm diameter cold bores, and utilize Nb-Ti superconductor operating in He II at 1.8 K. None of the three models had an iron flux-return yoke. The maximum central fields achieved are 8.0, 8.6, and 9.1 tesla - all short-sample performance at 1.8 K for the conductors used. At 4.3 K the maximum central fields are from 1.5 to 2.0 tesla lower. In one design, the superconductor is arranged in four concentric cylindrical layers, sometimes called a four-shell geometry. With higher current density Nb-Ti we expect this design to reach 10 tesla central field and a two layer design to reach 8 tesla. The other design uses 8 flat pancakes with upturned ends. Improved Nb-Ti should also allow this design to reach 10 tesla central field. This geometry is being used for our Nb/sub 3/Sn wind-and-react dipole to be operated in He I at 4.3 K.