Design and experimental results of the Nb/sub 3/Sn double insert for an 18 tesla, 100 mm free bore solenoid

A high field, large free bore (more than 100 mm at. 4.2 K) solenoid for the LASA lab of INFN-Milan is almost completed. The Nb/sub 3/Sn insert, constituted by two coils independently supplied, is designed to provide a central field in excess of 18 tesla when immersed in the background field of 8 tesla generated by a NbTi solenoid of 550 mm room temperature bore (this last solenoid already being in operation). The construction technique-W&R followed by vacuum impregnation-is described and the results of tests and measurements carried out on models wound with the real conductor (a NbSn/Cu Rutherford flat cable) are reported.