Optimizing IR Design for LHC Luminosity Upgrade Peter McIntyre and Akhdiyor Sattarov Texas A&M University

To optimize an IR insertion: makes the lenses strong put them close to the IP Maximize gradients in quad triplet Inquire with experiments how close to go –~12 m providing transverse size <30 cm dia. Develop designs for quads, dipoles that can tolerate high radiation, high heat

Preliminary IR

Q 1 is in harm’s way, but moving closer actually reduces losses D1D1 Q1Q1 Multiplicity ~ f(  ) e -bt E particle ~ p t /  So energy flow concentrates strongly down the beam direction.

Design Q 1 using structured cable 6-on-1 cabling of Nb 3 Sn strand around thin-wall inconel X750 spring tube Draw within a thicker inconel 718 jacket Interior is not impregnated – only region between cables in winding Volumetric cooling to handle volumetric heating from particle losses

Ironless Quadrupole for Q T/m 6 K supercritical cooling

Q 2, Q 3 : push gradient using block-coil Nb 3 Sn quadrupoles 334 K supercritical cooling (no iron) 390 K superfluid cooling (w/iron)

D 1 : levitated-pole dipole Cold iron pole piece, warm iron flux return. Cancel Lorentz forces on coils, pole steel. 8.7 T 4.5 K

This approach to IR elements opens new opportunities to optimizes IR optics Comparison to baseline IR: Reduce  * Reduce # of subsidiary bunch crossings Reduce sensitivity to error fields and placements Open space for another doublet to fully separate corrections in x, y. This is a work in progress. I need collaborators!