DESIGN AND EXPERIMENTAL RESULTS OF THE NB3SN 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 Nb3Sn insert, con stituted by two coils independently supplied, is designed to provide a central field in excess of 18 tesla when immersed in the background f ield of 8 tesla generated by a NbTi solenoid of 550 mm room temperatur e bore (this last solenoid already being in operation). The constructi on technique - W & R followed by vacuum impregnation - is described an d the results of tests and measurements carried out on models wound wi th the real conductor (a NbSn/Cu Rutherford flat cable) are reported.