Second mock-up coil for the MQYY magnet after winding and polymerization. 

In addition to the dipole and quadrupole magnets that guide and focus the charged particles, corrector magnets are used to cure imperfections in the magnets and compensate for alignment errors, Accelerating

In the HL-LHC, two 2-metre-long canted cosine theta magnets will be positioned near the insertion region of the ATLAS and CMS experiments and will be used as corrector magnets, CERN Bul