TB, KB, FG and CV, 06/07/16 

ILD MODELS FOR DETAILED BENCHMARKS SIMULATIONS

GENERAL GUILDELINES
-------------------

- 1 large and 1 small ILD models
- Large model with same dimensions and B field (3.5T) as DBD,
  updated for new L*
- Small model with Santander proposed dimensions (possibly fine tuned),
  including new L* and B field increased to 4T, with vertex inner radius,
  TPC inner radius and ECAL-HCAL depths same as for large model.
- Gaps between subdetectors same for large and small models.
- For both models, simulation of subdetectors to be updated
  for new L* geometry, known bugs, intrinsic material simulation
  improvements and improved service description.
- For large model, all subdetector internal parameters left unchanged
  compared to DBD, unless a clear better configuration has been
  found since then (in which case it should be also implemented
  for small model).
- For small model, same internal configuration as for large model,
  apart for parameters related to overall size (e.g. cell sizes)
  which can be adapted.
- Optimisation of parameters not related to the 2 model sizes
  (e.g. #calolayers) left to focused studies.

OPEN QUESTIONS TO SUBDETECTOR GROUPS
------------------------------------

Subdetector groups will be provided a new set of detector envelopes
for both models, to be defined by Frank and Karsten along the above lines.
They will be asked to check that they can fit their detector within
the new envelopes, and provide updated description of the internal
structure of their detectors, along the above guidelines, including
answering the following questions:

CDI :
- for small model, yoke depth necessary to keep stray fields
  below 50G with 4T field of smaller coil ?
  -> need new field simulation ( -> Uwe Schneekloth )
- for small model, check impact on magnet thickness of a possible design
  for a max field of 4.5T
- For both models, provide complete field map for simulation

VERTEX:
- Same geometry as for DBD (for both models) ?

TRACKER/Si:
- For both models, same FTD geometry as for DBD ?
- For both models, do we need a more realistic SIT/SET geometric implementation ?
  (current simulation as polyhedral barrels with touching wafers without gaps/overlaps)
- For small model, needs adapted SET geometry 
  (simple scaling keeping the #wafers/staves constant ?)

TRACKER/TPC:
- for small model, decrease pad sizes along reduction of TPC level arm,
  or keep pads unchanged ?

ECALO:
- For small model, adapt the cell sizes/ granularity to reduced radius ?
- For both models, agree to remove pre-shower Si-layer in the barrel
  (assuming SET remains in simulation) ?

HCALO:
- for small model, adapt the cell sizes/ granularity to reduced radius ?

VFS:
- Needs adaptation to new L* (both models)
- Include new simulation for LHcal (both models)

IRON INSTRUMENTATION :
- For small model, adapt iron instrumentation to intrumentation gaps
  with smaller radius (same number of gaps as in large model)