Cu- and Al-stabilized Nb3Sn multifilamentary conductors and their stability against heat pulses under bath cooling conditions

Composite conductors were made by soldering together sandwich like a prereacted flat cable of Nb3Sn multifilamentary strands with a high purity aluminium tape and in a second case additionally with a thin stainless steel ribbon. The stability behaviour of these composites against heat pulses in liquid helium cooling at 4.2 K was studied. It turned out that the aluminium is an excellent stabilizer although the Al/SC ratio had only a value of 1.33 compared to a similar copper stabilized conductor of a Cu/SC ratio of 2.64. The aluminium improved the current sharing behaviour and kept the consequences of defects in the Nb3Sn layers in the range of the losses of a soldered joint.