A Model Superconducting Helical Undulator Wound Using a Wind and React ${\rm MgB}_{2}$ Multifilamentary Wire

A short model helical undulator, 250 mm long, with a period of 14 mm was designed, fabricated and then subsequently tested in a liquid helium bath. The helical coil was wound with stabilized multi-filamentary MgB
₂
strand, 0.5 mm in diameter, in a wind and react mode with S-glass insulation followed by vacuum epoxy impregnation. Beam aperture of the coil was 7 mm, winding bore diameter 8 mm, coil winding OD=18 mm and the 1010 Fe pole (flange) has an OD=19.05 mm. The coil was measured for
I

_c
and magnetic field in the bore at 4.2 K in a liquid helium bath. The bore field as a function of depth was also determined near the critical current at 4.2 K. The load line of the coil was compared to short sample
I

_c
values.