Very high gradient quadrupoles

High gradient superconducting quadrupoles are an essential component of high energy hadron colliders, both in the arcs and in the insertions. The highest performance quadrupoles today are those for the Large Hadron Collider (LHC) at CERN. These 56 to 70 mm aperture magnets, developed in Europe, the United States, and Japan, reach gradients on the order of 250 T/m, which is near the limit for NbTi technology. Designs based on Nb/sub 3/Sn are now being developed, which are aimed at use in second generation LHC low-/spl beta/ insertions and in the next generation of very large hadron colliders (VLHC). These quadrupoles are planned to achieve gradients up to 300 T/m with the large aperture required for the LHC insertions or 450 T/m for smaller aperture arc quadrupoles for VLHC. Even higher gradients may be required for the VLHC final focus.