Common MDI

[aciarma]

Added Lumical, quadrupoles and magnetic fields to the common MDI folder for FCCee.

• [OK] Move LumiCal (from CLD_o2_v07) to common folder
• [OK] Add file with dimensions/materials related to MDI elements
• [OK] Add solenoids Fieldmap
• [OK] Add simple quadrupoles (these will change with the lattice, both field and position/dimension)
• [OK] Add a standalone master for MDI elements only (mainly for debug processes and tracking in LumiCal)
• Change detectors master xml to point to the common MDI files, and remove old MDI files from the detector folders
  - CLD (which version?)
  - [OK] IDEA_o1_v03
  - [OK] ALLEGRO_o1_v03

[aciarma]

I've changed the master compact file for IDEA_o1_v03 and ALLEGRO_o1_v03 to point to the common MDI folder for all the related elements, removed the files for LumiCal/beam pipe/beam instrumentation from the experiment folders and modified accordingly the DectDimensions.xml files.

Should I do the same for CLD? If yes, which version?

[aciarma]

the file FFQuads_v01 (default include) now is not a sensitive element anymore. If for specific needs the hits in the quadrupoles need to be studied, FFQuads_v01_sens.xml is the sensitive version to be used instead.

[danieljeans]

are these MDI models expected to be overlap-free yet? @Victor-Schwan and I think we are seeing several overlaps when using the overlap.mac macros in ddsim on both the MDI_standalone_o1_v01 and MDI_standalone_o1_v00 models.

I attach the output of the overlap checker for the two standalone models. (search for "detected" and you'll see the overlaps).

overlap_MDI_standalone_o1_v00.log
-> looks like up to ~2 cm overlaps around HOMabsorber

overlap_MDI_standalone_o1_v01.log
-> many 10~1000 micron overlaps between CAD elements

[danieljeans]

I propose applying g4 step limits to the interior of the beampipe, and the whole MDI region (in my experience this helps achieve accurate simulation of beamstrahlung (ie low pT charged particles) in non-uniform fields).
Adding something like:

<limitset name="mdi_limits">
   <limit name="step_length_max" particles="*" value="5.0" unit="mm" />
</limitset>

and adding the limits to the different MDI detectors, e.g. changing

<detector name="BeBeampipe" type="DD4hep_Beampipe_o1_v01" insideTrackingVolume="true" nocore="true" vis="BeamPipeVis">

to

<detector name="BeBeampipe" type="DD4hep_Beampipe_o1_v01" insideTrackingVolume="true" limits="mdi_limits" nocore="true" vis="BeamPipeVis">

should work OK, I think.

[BrieucF]

Are we sure this map contains only the fields from the anti-solenoid and assume a 0 detector field when produced? Otherwise we will "double count" the detector field there. By the way, "fieldMap" is very generic, can you find a more descriptive name for this file.

[atolosadelgado]

Hi @aciarma ,

Thank you for making this very complete PR!

Here are few comments:
v00:

1. Overlaps are found with the HOM absorber. However, CLD has no overlaps in its MDI, how is it possible?

          Overlap is detected for volume AV_4!BeamPipeShield_assembly_3#3!tube_TaShield_0_0#0:4 (G4SubtractionSolid) with HOMAbsorber_envelope_11:11 (G4UnionSolid)
          overlap at local point (38.0487,-33.0895,1241.63) by 4.41048 mm  (max of 124 cases)
--
          Overlap is detected for volume AV_4!BeamPipeShield_assembly_3#3!tube_TaShield_1_1#1:5 (G4SubtractionSolid) with HOMAbsorber_envelope_11:11 (G4UnionSolid)
          overlap at local point (-37.5385,-32.9308,-1209.05) by 4.5692 mm  (max of 94 cases)
--
          Overlap is detected for volume HOMAbsorber_envelope_11:11 (G4UnionSolid) with AV_4!BeamPipeShield_assembly_3#3!tube_TaShield_0_0#0:4 (G4SubtractionSolid)
          overlap at local point (-12.5365,34.1472,-389.019) by 1.48998 cm  (max of 4272 cases)
--
          Overlap is detected for volume AV_8!HOMAbsorbers_PunchThrough_assembly_12#12!tube_HOM1_0_0#0:13 (G4SubtractionSolid) with AV_4!BeamPipeShield_assembly_3#3!tube_TaShield_0_0#0:4 (G4SubtractionSolid)
          overlap at local point (0.553117,-31.1543,-388.835) by 1.96526 cm  (max of 5628 cases)
--
          Overlap is detected for volume AV_8!HOMAbsorbers_PunchThrough_assembly_12#12!tube_HOM1_1_1#1:14 (G4SubtractionSolid) with AV_4!BeamPipeShield_assembly_3#3!tube_TaShield_1_1#1:5 (G4SubtractionSolid)
          overlap at local point (0.785344,-31.6609,-388.835) by 1.96071 cm  (max of 5595 cases)

2. Variable QD0 min/max are defined twice, can we centralize it into the Dimensions and material compact file?
3. These variables QD0 have a comment that says potentially outdated, do you know if it means that the value is not valid anymore?
4. Centralize size variables from solenoid and antisolenoid in Dimensions and Materials compact file?
5. Move the definition of magnetic field of FFQ to another file, to be coherent with the solenoid/antisolenoid elements?

v01:
6. CAD design corresponding to water and AlBeMet volumes seem to have at least 1 facet with the wrong orientation, as reported during initializing the geometry:

-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : GeomSolids1001
      issued by : G4TessellatedSolid::SetSolidClosed()
Defects in solid: "Componente1"_shape_0xd5bd950 - some facets have wrong orientation!
*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------


-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : GeomSolids1001
      issued by : G4TessellatedSolid::SetSolidClosed()
Defects in solid: "Componente1"_shape_0xe064510 - some facets have wrong orientation!
*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------

7. I am not sure if it is related to the previous point, but the Geant4 navigator reports error around point r~25, z=+/-1111 (I think the units are mm). Please see the the attached file named MDI_v01_error_points.txt
   MDI_v01_error_points.txt

8. Regarding Daniel comment about region limits, I can take care of it in a future PR.

9. Regarding your question if CLD should be modified, we can leave it as it is for the moment, and let the CLD responsibles change to the central MDI.

Please, let me know if I can help somehow.