ILC Lattice Files Punch List
P. Tenenbaum, SLAC

Introduction

In October 2007, Mark Woodley assembled the first "complete" set of lattices for the ILC, from e- / e+ sources to IP and main dumps.  His results are documented in a presentation made at the ALCPG meeting. 

The goal of this document is to provide a complete list of known or possible outstanding problems with the lattices (a "punch list").  As
problems are corrected, they are removed from the list; as other problems are found, they are added to the list.  When the list is empty, the decks are ready.

Unfortunately, life is a bit more complicated than that!  What makes life more complicated is that we really want to do 4 things:
  1. Establish an internally-consistent set of lattice files that represent the Reference Design of the ILC as promulgated in the Reference Design Report -- regardless of whether some of the choices made for the RDR are sub-optimal and need to be revisited, or whether the lattice files are not well-written in terms of style and standards.
  2. Establish a set of lattices which are well-written and follow a set of standards that will ease maintenance and readability of the lattices.
  3. Revisit minor issues and tweak them in ways which improve the lattice but don't make much of a change to the cost, layout, etc, but make some improvement to performance.
  4. Revisit somewhat more major issues and tweak them in ways that will have a noticable change in the cost or layout.
To this end, we will have a total of 5 (!) punch lists:

  1. Changes that definitely need to be made to bring the lattices into conformity with the RDR.
  2. Items that may or may not need to be changed to bring lattices into conformity with the RDR ("check" items).
  3. Changes which are needed to bring the lattice files into conformity with the deckmastering standards (this list will be blank for now, since we haven't officially adopted any such standards; once we do have them we'll worry about this!).
  4. Changes which are cost-neutral, performance-enhancing, but which are not needed to come into conformity with RDR.
  5. Changes which impact cost and performance, but which are not needed to come into conformity with RDR.
With that in mind, here we go:

1.  Definite Changes for Conformity with RDR
  1. ESOURCE -- booster linac uses 8Cav0Q CMs rather than 9Cav0Q CMs
  2. ESOURCE -- geometry changes to match tunnel layout when PDRX VDOG included (see item below)
  3. ESOURCE -- ELTR ECOMP CM needs to be made std CM
  4. PSOURCE -- inconsistencies in photon transport start point
  5. PSOURCE -- booster linac uses 8Cav0Q CMs rather than 9Cav0Q CMs
  6. PSOURCE -- booster linac non-std CMs need to be made std length
  7. PSOURCE -- PLTR ECOMP CM needs to be made std CM
  8. PSOURCE -- incorrect x position of 400 MeV line from production target
  9. PSOURCE -- 400 MeV beamline should be closer to linac axis than ERETURN line, opposite of CFS drawings (see item below)
  10. PSOURCE -- horizontal dogleg into escalator tunnel needed (see item below)
  11. PSOURCE -- position and angle of "up escalator" not consistent with EESCALATOR in RTML (see item below)
  12. PSOURCE -- KAS lattice missing
  13. PSOURCE -- PLTR VDOG from floor to PDR elevation needed (see item below)
  14. PDR -- needs to move to correct elevation in DR tunnel, over EDR
  15. EDR -- DRI / DRX lattices inconsistent with EDR inj/ext straight lattices
  16. PDR -- DRI / DRX lattices inconsistent with EDR inj/ext straight lattices
  17. EDR -- DRI / DRX lattices not complete
  18. PDR -- DRI / DRX lattices not complete
  19. EDR -- production lattice decision not yet made
  20. PDR -- production lattice decision not yet made
  21. ERTML -- VDOG from e- DR elevation to EGETAWAY (ceiling) elevation missing (see item above)
  22. PRTML -- VDOG from e+ DR elevation to PGETAWAY elevation missing (see item above)
  23. ERTML -- x separation EGETAWAY vs PSOURCE incorrect
  24. PRTML -- x separation PGETAWAY vs ESOURCE incorrect
  25. ERTML -- escalator position and angle not consistent with PSOURCE (see item above)
  26. PRTML -- escalator position and angle not correct
  27. ERTML -- horizontal dogleg into linac tunnel needed (see item above)
  28. PRTML -- horizontal dogleg into linac tunnel needed
  29. ERTML -- 5 GeV beamline should be further from linac axis than PSOURCE, opp of CFS drawings (see item above)
  30. ERTML -- 3 dumplines not yet in production
  31. PRTML -- 3 dumplines not yet in production
  32. ELIN -- undulators missing from undulator lattice
  33. PLIN -- optics discrepancy at PLIN1 / PLIN2 boundary -- artifact of ELIN1 / ELIN2 design?
  34. EBDS -- DMLS drift needs to be removed
  35. PBDS -- DMLS drift needs to be removed
  36. ESOURCE -- dipole correctors and almost all BPMs missing
  37. PRTML -- Need to change length of straight section between arcs in DRX to match changes in ESOURCE.
2.  Items Which Must be Checked for Conformity with RDR
  1. ESOURCE -- spacing and segmentation for cryogenic support (requires Cryo involvement?)
  2. PSOURCE -- spacing and segmentation for cryogenic support (requires Cryo involvement?)
  3. PSOURCE -- 400 MeV prod line has correct vertial curvature
  4. PSOURCE -- 400 MeV lines can coexist with RTML 5 GeV lines (ie, no space conflicts)
  5. PSOURCE -- escalator produces correct elevation change (ceiling ML tunnel to floor source tunnel)
  6. PSOURCE -- switchyard to combine KAS and prod 400 MeV beams not too screwy
  7. EDR -- current circumference consistent with geometry of all other deckfiles
  8. PDR -- current circumference consistent with geometry of all other deckfiles
  9. ERTML -- straight and curved sections of RETURN line match straight and curved sections of ML/BC
  10. PRTML -- straight and curved sections of RETURN line match straight and curved sections of ML/BC
  11. ERTML -- vertical disperison match in ERETURN
  12. PRTML -- vertical dispersion match in PRETURN
  13. ERTML -- offset of ETURN HDOG and VDOG
  14. PRTML -- offset of PTURN HDOG and VDOG
  15. ELIN -- direction of arcs into / out of undulator
  16. ELIN -- curvature correct to get all BDS in 1 plane?  VARC needed from linac to BDS?
  17. PLIN -- curvature correct to get all BDS in 1 plane?  VARC needed from linac to BDS?
  18. ELIN -- vertical dispersion match
  19. PLIN -- vertical dispersion match
  20. All areas -- are pulsed extraction lines present?
  21. All areas -- are aisleways maintained?
  22. All areas -- do coexisting beamlines fit in same tunnel given expected tunnel diameter?
  23. All areas -- directions of bending of various arcs
3.  Changes Required for Conformity With Deckmastering Standards
  1. All areas -- use common, CALL'ed definitions file to load CM and other common element definitions
4.  Cost-Neutral, Performance-Enhancing Changes
  1. ESOURCE -- study minimizing system length
  2. PSOURCE -- study minimizing system length
  3. ERTML -- improve beta / eta matching in all areas
  4. PRTML -- improve beta / eta matching in all areas

5.  Changes which Impact Cost and Performance
  1. e-/e+ timing correction
  2. EBDS -- descope to 0.5 TeV CM only (IF APPROVED)
  3. PBDS -- descope to 0.5 TeV CM only (IF APPROVED)
  4. ESOURCE -- redesign to 31.5 MV/m nominal gradient
  5. PSOURCE -- redesign to 31.5 MV/m nominal gradient
  6. ERTML -- reduce packing fraction in dense areas to something achievable
  7. PRTML -- reduce packing fraction in dense areas to something achievable


quarkpt
17-Dec-2007

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