Commissioning of Horizontal-Bend Superconducting Magnet for Jefferson Lab's 11-GeV Super High Momentum Spectrometer

Commissioning of the characteristics of the superconducting high momentum spectrometer horizontal-bend (HB) magnet was presented. The precommissioning peer review of the magnet uncovered issues with eddy currents in the thermal shield, resulting in additional testing and modeling of the magnet. A three-stage test plan was discussed. A solution of using a small dump resistor and a warm thermal shield was presented. Analyses illustrated that it was safe to run the magnet to full test current. The HB magnet was successfully cooled at 4 K and reached its maximum test current of 4000 A.