Final Assembly and Factory Testing of the Jefferson Lab SHMS Spectrometer Quadrupole and Dipole Superconducting Magnets

Abstract

Jefferson Lab is constructing an 11-Gev/c electron spectrometer called the super high momentum spectrometer (SHMS) as part of the 12-GeV JLAB upgrade for experimental Hall C. Three of the five superconducting SHMS magnets are under construction at SigmaPhi in Vannes, France, as a result of an international competition for design and fabrication. The three magnets Q2 and Q3 60 cm bore quadrupoles and the 60 cm warm bore dipole are complete or near complete and have many design features in common. All three magnets share a common superconductor, collaring system, cryostat design, cold to warm support, cryogenic interface, burnout resistant current leads, dc power supply, quench protection, and instrumentation and controls. The three magnets are collared, installed in cryostats and welded up, and in various stages of final testing. The Q2 quadrupole is due to ship from France to America in August arriving during this ASC conference and has passed all final hipot, leak, and pressure tests. The dipole is in leak and pressure testing as of July 2016, whereas the Q3 quadrupole requires some outer vacuum vessel assembly. Delivery of the Q3 and dipole magnets will follow the Q2 at about one month intervals. Factory testing has included hipot and electrical tests, magnetic tests at low field, mechanical alignments to center the coils, leak tests, and ASME code required pressure tests. Upon installation in Hall C at JLAB cold testing will commence.