ILC Beam Delivery System / MDI Issues for LCC-phase (~<2016) Glen White, SLAC May AWLC14, Fermilab

BDS Cost Drivers “Tunnel length” and major infrastructure changes likely to be small BDS tuning “Value Engineering” – Emittance -> luminosity – Understand tradeoffs between design choices and impact on time required to deliver required luminosity – FFS complex, non-linear system. Mechanism of tuning system important.

Critical Issues Lattice design / optics (Thursday BDS sessions) – All lattices -> “complete” status for TDR baseline (250, 350, 500 GeV cm) both IR’s, (“no-detector” IR?), EXT, tune-up/abort lines e+ source (lengths correct w.r.t. timing) : BDS responsibility? linac->BDS transition – FFS optics properly matched and tuned for all configurations – Optics designs for low energy running 10 Hz specific items : bypass-lines? – Optimal BETA*? Balance between horizontal and vertical for given luminosity (-> beam dynamics/ tolerance studies) Determine largest practical L* configuration

Critical Issues Beam dynamics (BDS/Linac S2E session Tuesday) – Update dynamic tuning simulations (in S2E context) Evaluate credible luminosity delivery: folding in all error sources and countermeasures – Provide well-motivated and complete list of tolerances Magnet field accuracy, Multipoles, apertures, component alignment, mover capabilities, PS requirements Jitter tolerances – Crossing angle Smaller? Larger? Try to quantify risk from beam dynamics perspective – Specify incoming beam dynamics tolerances to accept from linac – Review vacuum requirements – Evaluate impact of having 2 different L* optics – Review of diagnostics/technical systems BPM resolution requirements? Where are movers really needed?

Critical Issues Collimation systems & backgrounds : re-evaluate – LW photon detection – Muon shielding requirements Demonstration of SC FD prototype (vibration tests) CF / BDS tunnel layout, equipment distribution, central region integration, MDI issues – load distributions – service tunnel – high-power dump enclosures – Muon shielding – Detector hall layout – Crab cavity integration (cryogenics) – SC Octupole cryogenetics – push-pull logistics

Less Critical Issues & Beyond Baseline Lattice design / optics – “Traditional” vs. baseline FFS Evaluate tuning efficiency – tail-folding octupoles – Phase-control of FFS Adequate number of matching quadrupoles? – Profile measurement at FFS IP-image point Split QF7 Additional LW infrastructure / technology Beam dynamics – Wakefield sources : specify complete list collimators beam pipes, transitions, ports, chambers, flanges etc BPMs – Capability to correct momentum dispersion within BDS Tweaker quads/skew-quads in chicanes? Commissioning (see joint BDS/MDI/CFS commissioning session) – Consider ability to diagnose fault conditions – Special IR “no-detector” configuration Need QD0 installation infrastructure? AUX FD quad/split QF1? Additional IP-based BPMs/profile monitor(s)?