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

Q1 is in harm’s way, but moving closer actually reduces losses

D1

Q1

Multiplicity ~ f() e-bt Eparticle ~ pt /

So energy flow concentrates strongly down the beam direction.

Design Q1 using structured cable

6-on-1 cabling of Nb3Sn 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 Q1

316 T/m

6 K supercritical cooling

Q2, Q3: push gradient usingblock-coil Nb3Sn quadrupoles

334 T/m @6 K supercritical cooling (no iron)

390 T/m @2 K superfluid cooling (w/iron)

D1: 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!