ILC Beam Delivery System / MDIIssues for LCC-phase (~<2016)

Glen White, SLACMay 14 2014

AWLC14, Fermilab

“All of this has happened before,and will happen again”

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)?