DetectorConstruction.cc

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/// \file B4/B4a/src/DetectorConstruction.cc
/// \brief Implementation of the B4::DetectorConstruction class
 
#include "DetectorConstruction.hh"
 
#include "G4Material.hh"
#include "G4NistManager.hh"
 
#include "G4Box.hh"
#include "G4LogicalVolume.hh"
#include "G4PVPlacement.hh"
#include "G4PVReplica.hh"
#include "G4GlobalMagFieldMessenger.hh"
#include "G4AutoDelete.hh"
 
#include "G4GeometryManager.hh"
#include "G4PhysicalVolumeStore.hh"
#include "G4LogicalVolumeStore.hh"
#include "G4SolidStore.hh"
 
#include "G4VisAttributes.hh"
#include "G4Colour.hh"
 
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
 
namespace B4
{
 
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G4ThreadLocal
G4GlobalMagFieldMessenger* DetectorConstruction::fMagFieldMessenger = nullptr;
 
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G4VPhysicalVolume* DetectorConstruction::Construct()
{
  // Define materials
  DefineMaterials();
 
  // Define volumes
  return DefineVolumes();
}
 
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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;
}
 
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G4VPhysicalVolume* DetectorConstruction::DefineVolumes()
{
  // Geometry parameters
  G4int nofLayers = 10;
  G4double absoThickness = 10.*mm;
  G4double gapThickness =  5.*mm;
  G4double calorSizeXY  = 10.*cm;
 
  auto layerThickness = absoThickness + gapThickness;
  auto calorThickness = nofLayers * 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
                 nofLayers,        // number of replica
                 layerThickness);  // witdth of replica
 
  //
  // Absorber
  //
  auto absorberS
    = new G4Box("Abso",            // its name
                 calorSizeXY/2, calorSizeXY/2, absoThickness/2); // its size
 
  auto absorberLV
    = new G4LogicalVolume(
                 absorberS,        // its solid
                 absorberMaterial, // its material
                 "Abso");          // its name
 
  fAbsorberPV = 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
  //
  auto gapS
    = new G4Box("Gap",             // its name
                 calorSizeXY/2, calorSizeXY/2, gapThickness/2); // its size
 
  auto gapLV
    = new G4LogicalVolume(
                 gapS,             // its solid
                 gapMaterial,      // its material
                 "Gap");           // its name
 
  fGapPV = 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 " << nofLayers << " 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;
}
 
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void DetectorConstruction::ConstructSDandField()
{
  // 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);
}
 
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}