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Geant4 Version: geant4-11-02-patch-01 [MT]
Operating System: Debian11
Compiler/Version:
CMake Version:
Hello Geant4 experts,
I have a probably rather simple question regarding my geometry set up. In my simulation I want to have a combination of a hadronic and electromagnetic calorimeter. It is a fixed target experiment and thus the HCal and ECal are placed downstream of the target as two rectangles. The HCal is supposed to wrap around the ECal. Meaning in the center of the HCal the ECal is placed. Additionally a slit for the beam is cut into both detectors. Now if I define my detectors in the following way:
// hcal parameters
G4double thickSi = 0.5*cm;
G4double thickAbHCal = 2*cm;
G4double numlayersHCal = 145;
G4double lengthXhcal = 250*cm;
G4double lengthYhcal = 270*cm;
G4Material* absorberHCal = nist->FindOrBuildMaterial("G4_Fe");
G4double thickhcal = numlayersHCal*(thickSi+thickAbHCal);
G4ThreeVector calorimeterPos = G4ThreeVector(0., 0., 350*cm+thickhcal/2);
// ecal parameters
G4double thickAb = 2*cm;
G4double numlayers = 30;
G4double lengthX = 47*cm;
G4double lengthY = 47*cm;
G4Material* absorber = nist->FindOrBuildMaterial("G4_W");
G4double thickecal = numlayers*(thickSi+thickAb);
G4ThreeVector calorimeterPos2 = G4ThreeVector(0., 0., 350*cm+thickecal/2);//387.5*cm);
G4ThreeVector holePosition(0., 0., 0.);
// HCal detector Box
G4Box* hcalDetectorBox = new G4Box("HcalDetectorBox", lengthXhcal/2, lengthYhcal/2, thickhcal/2);
G4Box* ecalDetectorBox = new G4Box("EcalDetectorBox", lengthX/2, lengthY/2, thickecal/2);
G4VSolid* hcalDetectorBoxWithHole = new G4SubtractionSolid("hcalDetectorBoxWithHole", hcalDetectorBox, ecalDetectorBox, 0, holePosition);
G4LogicalVolume* hcalDetectorLogical = new G4LogicalVolume(hcalDetectorBoxWithHole, air, "hcalDetectorLogical");
new G4PVPlacement(nullptr, calorimeterPos, hcalDetectorLogical, "hcalDetectorPhysical", worldLogical, false, 0, false);
// Layers inside HCal
G4Box* layers = new G4Box("Layer", lengthXhcal/2, lengthYhcal/2, thickSi+thickAbHCal);
G4LogicalVolume* layerLogical = new G4LogicalVolume(layers, air, "Layer");
G4double holeX = 48*cm;
G4double holeY = 48*cm;
G4double slitX = 125*cm; // needs to be half of the width of the hcal, as it only covers one side
G4double slitY = 10*cm;
G4ThreeVector hole2Position(lengthXhcal/4, 0., 0.);
// Absorber per layer
G4Box* AbsorberBoxHCal = new G4Box("AbsorberBoxHCal", lengthXhcal/2, lengthYhcal/2 , thickAbHCal/2);
G4Box* HoleBoxAbsorber = new G4Box("HoleBoxAbsorber", holeX/2, holeY/2, thickAbHCal/2);
G4Box* Hole2BoxAbsorber = new G4Box("Hole2BoxAbsorber", slitX/2, slitY/2, thickAbHCal/2);
G4VSolid* AbsorberBoxHCalWithHole = new G4SubtractionSolid("AbsorberBoxHCalWithHole", AbsorberBoxHCal, HoleBoxAbsorber, 0, holePosition);
G4VSolid* AbsorberBoxHCalWithHoles = new G4SubtractionSolid("AbsorberBoxHCalWithHoles", AbsorberBoxHCalWithHole, Hole2BoxAbsorber, 0, hole2Position);
G4LogicalVolume* AbsorberLogicalHCal = new G4LogicalVolume(AbsorberBoxHCalWithHoles, absorberHCal, "AbsorberLogicalHCal");
new G4PVPlacement(nullptr, G4ThreeVector(0., 0., -thickAbHCal/2), AbsorberLogicalHCal, "AbsorberHCalPhysical", layerLogical, false, 0, false);
// Si per layer
G4Box* SiBoxHCal = new G4Box("SiBoxHCal", lengthXhcal/2, lengthYhcal/2 , thickSi/2);
G4Box* HoleBoxSi = new G4Box("HoleBoxSi", holeX/2, holeY/2, thickSi/2);
G4Box* Hole2BoxSi = new G4Box("Hole2BoxSi", slitX/2, slitY/2, thickSi/2);
G4VSolid* SiBoxHCalWithHole = new G4SubtractionSolid("SiBoxHCalWithHole", SiBoxHCal, HoleBoxSi, 0, holePosition);
G4VSolid* SiBoxHCalWithHoles = new G4SubtractionSolid("SiBoxHCalWithHoles", SiBoxHCalWithHole, Hole2BoxSi, 0, hole2Position);
G4LogicalVolume* SiLogicalHCal = new G4LogicalVolume(SiBoxHCalWithHoles, silicon, "SiLogicalHCal");
new G4PVPlacement(nullptr, G4ThreeVector(0., thickSi/2), SiLogicalHCal, "SiHCalPhysical", layerLogical, false, 0, false);
new G4PVReplica("Layer", layerLogical, hcalDetectorLogical, kZAxis, numlayersHCal, thickSi+thickAbHCal);
// ECal detector box
//G4Box* ecalDetectorBox = new G4Box("EcalDetectorBox", lengthX/2, lengthY/2, thickecal/2); // defined this above for creating hole in hcal
G4LogicalVolume* ecalDetectorLogical = new G4LogicalVolume(ecalDetectorBox, air, "ecalDetectorLogical");
G4PVPlacement* ecalDetectorBoxPhysical = new G4PVPlacement(nullptr, calorimeterPos2, ecalDetectorLogical, "ecalDetectorPhysical", worldLogical, false, 0, true);
// Layers
G4Box* layersECal = new G4Box("LayerECal", lengthX/2, lengthY/2, thickSi+thickAb);
G4LogicalVolume* layerECalLogical = new G4LogicalVolume(layersECal, air, "LayerECal");
// Definition position hole
G4ThreeVector holeEcalPosition(lengthX/4, 0., 0.);
G4double slitecalX = 47*cm/2;
// Absorber per layer
G4Box* AbsorberBox = new G4Box("AbsorberBox", lengthX/2, lengthY/2 , thickAb/2);
G4Box* HoleEcalBoxAbsorber = new G4Box("Hole2BoxAbsorber", slitecalX/2, slitY/2, thickAb/2);
G4VSolid* AbsorberBoxECalWithHole = new G4SubtractionSolid("AbsorberBoxECalWithHole", AbsorberBox, HoleEcalBoxAbsorber, 0, holeEcalPosition);
G4LogicalVolume* AbsorberLogical = new G4LogicalVolume(AbsorberBox, absorber, "AbsorberLogical");
G4PVPlacement* AbsorberPhysical = new G4PVPlacement(nullptr, G4ThreeVector(0., 0., -thickAb/2), AbsorberLogical, "AbsorberPhysical", layerECalLogical, false, 0, false);
// Si per layer
G4Box* SiBox = new G4Box("SiBox", lengthX/2, lengthY/2 , thickSi/2);
G4Box* HoleEcalBoxSi = new G4Box("Hole2BoxSi", slitecalX/2, slitY/2, thickSi/2);
G4VSolid* SiBoxECalWithHole = new G4SubtractionSolid("SiBoxECalWithHole", SiBox, HoleEcalBoxSi, 0, holeEcalPosition);
G4LogicalVolume* SiLogical = new G4LogicalVolume(SiBox, silicon, "SiLogical");
G4PVPlacement* SiPhysical = new G4PVPlacement(nullptr, G4ThreeVector(0., 0., thickSi/2), SiLogical, "SiPhysical", layerECalLogical, false, 0, false);
new G4PVReplica("LayerECal", layerECalLogical, ecalDetectorLogical, kZAxis, numlayers, thickSi+thickAb);
I get a error message that the ECal and HCal physical volumes are overlapping. Up to now I have not been able to find, why it is that they overlap. One idea is that the boolean SubtractionSolid operation creates the holes, but they are still seen as part of the detector volume and thus overlap with the ECal once I place it. The detector set up works fine, if I move the ECal in the z-direction further upstream for example.
So I wonder if I need to do something different when defining the detectors. One option would be to create the HCal out of 4 rectangles such that the hole for the ECal and the slit are taken into account.
I would be very happy for any kind of help with this issue!
Kind regards,
Laney Klipphahn
