Fabrication and Test of a ${\rm Nb}_{3}{\rm Sn}$ Model Magnet With Ceramic Insulation for the Next Generation Undulator of the LHC

The future run of the Large Hadron Collider with lead ions will require important modifications in the synchrotron radiation profile monitor system, which at present comprises two superconducting undulators wound from Nb-Ti conductor, delivering 5 T in a 60 mm gap, and with a period of 280 mm. Whilst the gap and the nominal field of the future undulators will remain the same, the period shall be 140 mm, which translates to a peak field of over 8 T in the coils and hence requires the use of Nb₃Sn technology. In this paper the electromagnetic design of the undulator is summarized. We describe the fabrication of a race-track coil wound with a 0.8 mm diameter Nb₃Sn strand with ceramic insulation. Finally, the results of successful tests made at 4.3 K and 1.9 K in a mirror configuration are presented. 10 T at 4.3 K and 11.5 T at 1.9 K were measured in the yoke gap, thus validating this concept for the future undulator.