Beginner with Geant4, we are trying to simulate 4 slabs (infinite planar medium) with infinite gamma source.
Other codes, e.g. in nuclear reactor physics, already have this simple geometry ready. I have to be most compliant with these codes for the purpose of comparison of the implemented physics.
From what I understand, to simulate this kind of geometry in Geant-4, we have to go through G4Box.
Am I Right ? To make it really infinite, can I mention y and z dimensions that are infinite?
new G4Box(“Slab1” ,0.5*(x2-x1),1E+28 * cm,1E+28 * cm) ;
new G4Box(“Slab2” ,0.5*(x3-x2),1E+28 * cm,1E+28 * cm) ;
new G4Box(“Slab3” ,0.5*(x4-x3),1E+28 * cm,1E+28 * cm) ;
new G4Box(“Slab4” ,0.5*(x5-x4),1E+28 * cm,1E+28 * cm) ;
new G4Box(“World” ,1E+28*cm ,1E+28 * cm,1E+28 * cm) ;
Then, we define our logical volumes, followed by the physical volumes. This “1E + 28 * cm” corresponds exactly to what the code in reactor physics recognizes as infinite.
I tried a simulation going with this methodology, but I have overlapping issues between slab 2 and 4 which appear at infinite positions…
Checking overlaps for volume Slab1 (G4Box) … OK!
Checking overlaps for volume Slab2 (G4Box) … OK!
Checking overlaps for volume Slab3 (G4Box) … OK!
Checking overlaps for volume Slab4 (G4Box) …
-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : GeomVol1002
issued by : G4PVPlacement::CheckOverlaps()
Overlap with volume already placed !
Overlap is detected for volume Slab4:0 (G4Box)
with Slab2:0 (G4Box) volume’s
local point (0,-2.40287e+28,3.5745e+28), overlapping by at least: 1 cm
NOTE: Reached maximum fixed number -1- of overlaps reports for this volume !
*** This is just a warning message. ***
Unfortunately, at the moment, I don’t have the visualization capabilities to see further. So your response will help a lot.
Any advice is welcome.