Q.41:Linac Lattice

1
Q.41Linac Lattice Focusing (on behalf of WG1)

• Conservative choice TESLA spacing of 24 cavities
  per quad
• Most thoroughly studied (working lattices exist)
• Cryomodules of 8 or 12 cavities OK
• Split-tune (75/60 or more) provides protection
  against mode-rotation LRWFs
• Cost saving options
• High energy part of the Linac is more robust
  (smaller emittance dilution) and
• larger quad spacing here is cost saving
• Weaker focusing even in low-energy end Hints
  that smaller emittance growth
• possible studies ongoing
• Depends on several factors
• Achievable cavity alignment to cryomodules
• Presence or absence of HOM BPMs and cryomodules
  movers
• Different steering/tuning algorithms (11, DFS,
  BA, Kobus method) were demonstrated
• need more understanding of possible limitations
• benchmarking among diff. codes.
• Would like Quads to be separated from RF cavities