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alcap-org / g4sim

Simulation toolkit based on Geant4 and ROOT
http://wuchen1106.github.io/g4sim/
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Overlapping geometry #41

Closed thnam closed 10 years ago

thnam commented 10 years ago

Currently there is one overlap in our geometry:

Checking overlaps for volume TargetBorderShielding ... OK!
Checking overlaps for volume BeamWindow ... OK!
Checking overlaps for volume BeamWindowT ... 
-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : GeomVol1002
      issued by : G4PVPlacement::CheckOverlaps()
Overlap with volume already placed !
          Overlap is detected for volume BeamWindowT
          with MuTrigger volume's
          local point (3.77962,43.7113,84.8), overlapping by at least: 200 um 
NOTE: Reached maximum fixed number -1- of overlaps reports for this volume !
*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------

The offending volume is the BeamWindowT (appears to be the black tape outside of the beam port) in every subgeometry configuration: https://github.com/alcap-org/g4sim/blob/master/alcap/configure/sub_all/subgeo_default#L67-L69

    T 0 Rp1I thTp 0 360 BeamWindowT 1 World Plastic none S pRw0+thw0/2+thTp/2 0 180 0 0 0

An easy fix for this is pull the MuTrigger block back a bit:

-       B    XTr   XTr   LTr    MuTrigger    1     World     Air          none         S pRTr  0    180     0    0    0
+       B    XTr   XTr   LTr    MuTrigger    1     World     Air          none         S pRTr+thTp  0    180     0    0    0

Another issue is the tape we used seems to be typical electrical tape made of polyvinyl chloride (density 1.3), but assigned as Plastic (density ~ 0.95 in the material list). I added the PVC material and set it accordingly.

thnam commented 10 years ago

The fix is applied on SiR2, Al100 and the default subgeo.

AndrewEdmonds11 commented 10 years ago

Thanks, Nam. I'll be sure to make the same correction with the files I use.

thnam commented 10 years ago

So I was wrong about the black things in front of beam ports. It should be black paper (Tedlar®, made of PVF), the tape was just keeping the paper in place. I changed the layer to PVF.