Aperture limitations for 2nd generation Nb/sub 3/Sn LHC IR quadrupoles

One of the straightforward ways towards the higher luminosity in the LHC is a replacement of the present 70 mm NbTi quadrupoles with Nb/sub 3/Sn quadrupoles which would provide the same field gradient but in a larger aperture. Conceptual designs of such magnets with 90 mm aperture have been developed and studied. This paper discusses the possibilities and limitations of further increasing the aperture of Nb/sub 3/Sn low-beta quadrupoles, and shows that an aperture up to 110 mm is possible.