Experimental determination of stability margin in a 27 strand bronze matrix, Nb3Sn cable-in-conduit conductor

A small coil of internally cooled cabled superconductor was fabricated for experimental determination of the stability margin. The conductor is 27 strands of Nb3Sn in a bronze matrix. The sheath material is JBK-75 superalloy. The bifilar coil was potted in epoxy in the annulus of a pulse coll set. Experimental results are presented defining critical pulse energy as a function of normalized operating current and background field. The relationships between dB/dt, pulse energy and stability margin are derived by calculation and confirmed by experimental calibration.