A 9.1-T iron-free Nb- Ti dipole magnet with pancake windings

An eight-pancake Nb-Ti dipole magnet with bent-up ends and called D-10B has been built and tested. This magnet is a Nb-Ti version of a Nb3Sn magnet designed to produce a 10-tesla dipole field in a 40 mm diameter aperture. The pancake design is used for the heavy 12,000 ampere Nb3Sn cable because of the mechanical difficulty in winding such a heavy cable into the conventional nested cylindrical shell configuration with a 2'' inner winding diameter. The Nb-Ti version operates at 1.8 K in helium II, has superconducting cable half as thick as the Nb3Sn cable, and operates at half the current (6,000 amperes) at 10 tesla. Both magnets are approximately one meter long. D-10B was tested from January 26 to February 2, 1983, and reached short-sample performance in both helium I and helium II after moderate training. The central field at 4.3 K is 7.0 tesla and at 1.8 K is 9.1 tesla. Ramp rate sensitivity and cyclic heating data were also measured