Limit to surface thickness

Geometry, Fields and Transportation
1

Hello!
I’m trying to build a detector geometry with following dimensions:

G4Box : 200 um x 200 um x 200 um

I get the following error:

“Dimensions too small for Solid”

Is it possible that geant4 is not able to build such small geometries? I have not read about any limitations in the manuals.
Thanks for helping

1 Like
2

There is limitation for G4Box, but it is much-much smaller than 200 um = 0.2 mm

  if (pX < 2*kCarTolerance ||
      pY < 2*kCarTolerance ||
      pZ < 2*kCarTolerance)  // limit to thickness of surfaces                                                          
  {
    std::ostringstream message;
    message << "Dimensions too small for Solid: " << GetName() << "!" << G4endl
            << "     hX, hY, hZ = " << pX << ", " << pY << ", " << pZ;
    G4Exception("G4Box::G4Box()", "GeomSolids0002", FatalException, message);
  }

where kCarTolerance = 10^-9 mm

BTW, the error message should contain the dimensions of the box, please check.

3

I also encountered the same problem, I guess you used G4int to define the length of the geometry, you should use G4double with better precision