DetectorConstruction.cc

Go to the documentation of this file.

// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
 
#include "DetectorConstruction.hh"
 
#include "CalorimeterSD.hh"
 
#include "G4OCCT/G4OCCTSolid.hh"
 
#include "G4AutoDelete.hh"
#include "G4Box.hh"
#include "G4Colour.hh"
#include "G4GlobalMagFieldMessenger.hh"
#include "G4LogicalVolume.hh"
#include "G4Material.hh"
#include "G4NistManager.hh"
#include "G4PVPlacement.hh"
#include "G4PVReplica.hh"
#include "G4PhysicalConstants.hh"
#include "G4SDManager.hh"
#include "G4SystemOfUnits.hh"
#include "G4VisAttributes.hh"
 
#include <string>
 
namespace B4c {
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4ThreadLocal G4GlobalMagFieldMessenger* DetectorConstruction::fMagFieldMessenger = nullptr;
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4VPhysicalVolume* DetectorConstruction::Construct() {
  // Define materials
  DefineMaterials();
 
  // Define volumes
  return DefineVolumes();
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void DetectorConstruction::DefineMaterials() {
  // Lead material defined using NIST Manager
  auto nistManager = G4NistManager::Instance();
  nistManager->FindOrBuildMaterial("G4_Pb");
 
  // Liquid argon material
  G4double a; // mass of a mole;
  G4double z; // z=mean number of protons;
  G4double density;
  new G4Material("liquidArgon", z = 18., a = 39.95 * g / mole, density = 1.390 * g / cm3);
  // The argon by NIST Manager is a gas with a different density
 
  // Vacuum
  new G4Material("Galactic", z = 1., a = 1.01 * g / mole, density = universe_mean_density,
                 kStateGas, 2.73 * kelvin, 3.e-18 * pascal);
 
  // Print materials
  G4cout << *(G4Material::GetMaterialTable()) << G4endl;
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4VPhysicalVolume* DetectorConstruction::DefineVolumes() {
  // Geometry parameters
  fNofLayers             = 10;
  G4double absoThickness = 10. * mm;
  G4double gapThickness  = 5. * mm;
  G4double calorSizeXY   = 10. * cm;
 
  auto layerThickness = absoThickness + gapThickness;
  auto calorThickness = fNofLayers * layerThickness;
  auto worldSizeXY    = 1.2 * calorSizeXY;
  auto worldSizeZ     = 1.2 * calorThickness;
 
  // Get materials
  auto defaultMaterial  = G4Material::GetMaterial("Galactic");
  auto absorberMaterial = G4Material::GetMaterial("G4_Pb");
  auto gapMaterial      = G4Material::GetMaterial("liquidArgon");
 
  if (!defaultMaterial || !absorberMaterial || !gapMaterial) {
    G4ExceptionDescription msg;
    msg << "Cannot retrieve materials already defined.";
    G4Exception("DetectorConstruction::DefineVolumes()", "MyCode0001", FatalException, msg);
  }
 
  //
  // World
  //
  auto worldS = new G4Box("World",                                           // its name
                          worldSizeXY / 2, worldSizeXY / 2, worldSizeZ / 2); // its size
 
  auto worldLV = new G4LogicalVolume(worldS,          // its solid
                                     defaultMaterial, // its material
                                     "World");        // its name
 
  auto worldPV = new G4PVPlacement(nullptr,         // no rotation
                                   G4ThreeVector(), // at (0,0,0)
                                   worldLV,         // its logical volume
                                   "World",         // its name
                                   nullptr,         // its mother  volume
                                   false,           // no boolean operation
                                   0,               // copy number
                                   fCheckOverlaps); // checking overlaps
 
  //
  // Calorimeter
  //
  auto calorimeterS = new G4Box("Calorimeter",                                         // its name
                                calorSizeXY / 2, calorSizeXY / 2, calorThickness / 2); // its size
 
  auto calorLV = new G4LogicalVolume(calorimeterS,    // its solid
                                     defaultMaterial, // its material
                                     "Calorimeter");  // its name
 
  new G4PVPlacement(nullptr,         // no rotation
                    G4ThreeVector(), // at (0,0,0)
                    calorLV,         // its logical volume
                    "Calorimeter",   // its name
                    worldLV,         // its mother  volume
                    false,           // no boolean operation
                    0,               // copy number
                    fCheckOverlaps); // checking overlaps
 
  //
  // Layer
  //
  auto layerS = new G4Box("Layer",                                               // its name
                          calorSizeXY / 2, calorSizeXY / 2, layerThickness / 2); // its size
 
  auto layerLV = new G4LogicalVolume(layerS,          // its solid
                                     defaultMaterial, // its material
                                     "Layer");        // its name
 
  new G4PVReplica("Layer",         // its name
                  layerLV,         // its logical volume
                  calorLV,         // its mother
                  kZAxis,          // axis of replication
                  fNofLayers,      // number of replica
                  layerThickness); // width of replica
 
  //
  // Absorber — loaded from STEP file via G4OCCTSolid::FromSTEP
  //
  // The STEP box is centered at the origin and spans
  // ±calorSizeXY/2 in x and y, ±absoThickness/2 in z.
  //
  const std::string stepDir = G4OCCT_B4C_STEP_DIR;
  auto* absorberS           = G4OCCTSolid::FromSTEP("Abso", stepDir + "/absorber.step");
 
  auto absorberLV = new G4LogicalVolume(absorberS,        // its solid
                                        absorberMaterial, // its material
                                        "AbsoLV");        // its name
 
  new G4PVPlacement(nullptr,                                  // no rotation
                    G4ThreeVector(0., 0., -gapThickness / 2), // its position
                    absorberLV,                               // its logical volume
                    "Abso",                                   // its name
                    layerLV,                                  // its mother  volume
                    false,                                    // no boolean operation
                    0,                                        // copy number
                    fCheckOverlaps);                          // checking overlaps
 
  //
  // Gap — loaded from STEP file via G4OCCTSolid::FromSTEP
  //
  // The STEP box is centered at the origin and spans
  // ±calorSizeXY/2 in x and y, ±gapThickness/2 in z.
  //
  auto* gapS = G4OCCTSolid::FromSTEP("Gap", stepDir + "/gap.step");
 
  auto gapLV = new G4LogicalVolume(gapS,        // its solid
                                   gapMaterial, // its material
                                   "GapLV");    // its name
 
  new G4PVPlacement(nullptr,                                  // no rotation
                    G4ThreeVector(0., 0., absoThickness / 2), // its position
                    gapLV,                                    // its logical volume
                    "Gap",                                    // its name
                    layerLV,                                  // its mother  volume
                    false,                                    // no boolean operation
                    0,                                        // copy number
                    fCheckOverlaps);                          // checking overlaps
 
  //
  // print parameters
  //
  G4cout << G4endl << "------------------------------------------------------------" << G4endl
         << "---> The calorimeter is " << fNofLayers << " layers of: [ " << absoThickness / mm
         << "mm of " << absorberMaterial->GetName() << " + " << gapThickness / mm << "mm of "
         << gapMaterial->GetName() << " ] " << G4endl
         << "------------------------------------------------------------" << G4endl;
 
  //
  // Visualization attributes
  //
  worldLV->SetVisAttributes(G4VisAttributes::GetInvisible());
  calorLV->SetVisAttributes(G4VisAttributes(G4Colour::White()));
 
  //
  // Always return the physical World
  //
  return worldPV;
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void DetectorConstruction::ConstructSDandField() {
  // G4SDManager::GetSDMpointer()->SetVerboseLevel(1);
 
  //
  // Sensitive detectors
  //
  auto absoSD = new CalorimeterSD("AbsorberSD", "AbsorberHitsCollection", fNofLayers);
  G4SDManager::GetSDMpointer()->AddNewDetector(absoSD);
  SetSensitiveDetector("AbsoLV", absoSD);
 
  auto gapSD = new CalorimeterSD("GapSD", "GapHitsCollection", fNofLayers);
  G4SDManager::GetSDMpointer()->AddNewDetector(gapSD);
  SetSensitiveDetector("GapLV", gapSD);
 
  //
  // Magnetic field
  //
  // Create global magnetic field messenger.
  // Uniform magnetic field is then created automatically if
  // the field value is not zero.
  G4ThreeVector fieldValue;
  fMagFieldMessenger = new G4GlobalMagFieldMessenger(fieldValue);
  fMagFieldMessenger->SetVerboseLevel(1);
 
  // Register the field messenger for deleting
  G4AutoDelete::Register(fMagFieldMessenger);
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
} // namespace B4c