Test Dipole Magnets for the Tristan Superconducting Proton Ring

Two test dipole magnets have been constructed for the TRISTAN superconducting proton ring. The magnet is a warm bore and warm iron type. The inner coil diameter is 14 cm and the coil length is 1.1 m. The Fermilab type collaring coil structure is adopted for its strong mechanical properties at high stressed conditions. The coil is wound in double shells with keystoned compacted cables of 27 NbTi strands. After 21 training cycles, the first magnet has been excited successfully up to 5.1 T in the central field, and the second magnet has been excited also up to 5.25 T after 12 quenches.