The detector construction (via TGeo ) More...

#include <DetectorConstruction.h>

Inheritance diagram for VMC::Gflash::DetectorConstruction:

Public Member Functions
	DetectorConstruction ()

virtual	~DetectorConstruction ()

void	Construct ()

Detailed Description

The detector construction (via TGeo )

Geant4 gflash example adapted to Virtual Monte Carlo.

Author: I. Hrivnacova; IPN, Orsay

Definition at line 39 of file DetectorConstruction.h.

Constructor & Destructor Documentation

◆ DetectorConstruction()

VMC::Gflash::DetectorConstruction::DetectorConstruction ( )

Default constuctor

Definition at line 42 of file DetectorConstruction.cxx.

                                             : TObject()
  {
    /// Default constuctor
  }

◆ ~DetectorConstruction()

VMC::Gflash::DetectorConstruction::~DetectorConstruction ( )

virtual

Destructor

Definition at line 48 of file DetectorConstruction.cxx.

  {
    /// Destructor
  }

Member Function Documentation

◆ Construct()

void VMC::Gflash::DetectorConstruction::Construct ( )

Construct geometry using TGeo modeller

Definition at line 58 of file DetectorConstruction.cxx.

  {
    /// Construct geometry using TGeo modeller
 
    // Create Root geometry manager
    new TGeoManager("Gflash_geometry", "Gflash VMC example geometry");
 
    // Elements
    //
    Double_t z, a;
    TGeoElement* elN = new TGeoElement("Nitrogen", "N", z = 7., a = 14.01);
    TGeoElement* elO = new TGeoElement("Oxygen", "O", z = 8., a = 16.00);
    TGeoElement* elW = new TGeoElement("Tungsten", "W", z = 74., a = 183.84);
    TGeoElement* elPb = new TGeoElement("Lead", "Pb", z = 82., a = 207.2);
 
    // Materials
    //
    // G4_Air
    Double_t density;
    TGeoMixture* matAir = new TGeoMixture("AirA", 2, density = 1.29e-03);
    matAir->AddElement(elN, 0.7);
    matAir->AddElement(elO, 0.3);
 
    // G4_Air
    TGeoMixture* matAir2 = new TGeoMixture("AirB", 2, density = 1.29e-03);
    matAir2->AddElement(elN, 0.7);
    matAir2->AddElement(elO, 0.3);
 
    // G4_PbWO4
    TGeoMixture* matPbWO4 = new TGeoMixture("PbWO4", 3, density = 8.28);
    matPbWO4->AddElement(elO, 4);
    matPbWO4->AddElement(elW, 1);
    matPbWO4->AddElement(elPb, 1);
 
    // Tracking medias (defaut parameters)
    //
 
    // Paremeters for tracking media
    Double_t param[20];
    param[0] = 0;     // isvol  - Not used
    param[1] = 2;     // ifield - User defined magnetic field
    param[2] = 10.;   // fieldm - Maximum field value (in kiloGauss)
    param[3] = -20.;  // tmaxfd - Maximum angle due to field deflection
    param[4] = -0.01; // stemax - Maximum displacement for multiple scat
    param[5] = -.3;   // deemax - Maximum fractional energy loss, DLS
    param[6] = .001;  // epsil - Tracking precision
    param[7] = -.8;   // stmin
    for (Int_t i = 8; i < 20; ++i) param[i] = 0.;
 
    Int_t mediumId = 0;
    TGeoMedium* medAir = new TGeoMedium("AirA", ++mediumId, matAir, param);
    TGeoMedium* medAir2 = new TGeoMedium("AirB", ++mediumId, matAir2, param);
    TGeoMedium* medPbWO4 = new TGeoMedium("PbWO4", ++mediumId, matPbWO4, param);
 
    // Volumes
    //
 
    // The Experimental Hall
    Double_t experimentalHall_x = 1000.;
    Double_t experimentalHall_y = 1000.;
    Double_t experimentalHall_z = 1000.;
 
    TGeoShape* experimentalHall_box = new TGeoBBox("expHall_box",
      experimentalHall_x,  // x size
      experimentalHall_y,  // y size
      experimentalHall_z); // z size
 
    TGeoVolume* experimentalHall_log =
      new TGeoVolume("ExpHall_log", experimentalHall_box, medAir);
    gGeoManager->SetTopVolume(experimentalHall_log);
 
    //------------------------------
    // Calorimeter segments
    //------------------------------
    // Simplified `CMS-like` PbWO4 crystal calorimeter
 
    Int_t nbOfCrystals = 10; // this are the crystals PER ROW in this example
                             // cube of 10 x 10 crystals
                             // don't change it @the moment, since
                             // the readout in event action assumes this
                             // dimensions and is not automatically adapted
                             // in this version of the example :-(
    Double_t crystalWidth = 3.;
    Double_t crystalLenght = 24.;
    Double_t calo_xside = (crystalWidth * nbOfCrystals) + 1.;
    Double_t calo_yside = (crystalWidth * nbOfCrystals) + 1.;
    Double_t calo_zside = crystalLenght;
 
    TGeoShape* calo_box = new TGeoBBox("CMS_calorimeter", // its name
      calo_xside / 2.,                                    // size
      calo_yside / 2., calo_zside / 2.);
    TGeoVolume* calo_log = new TGeoVolume("Calo_log", calo_box, medAir2);
 
    Double_t Xpos = 0.0;
    Double_t Ypos = 0.0;
    Double_t Zpos = 100.0;
 
    // TGeoRotation* rot = new TGeoRotation();
    // rot->RotateY(-phi);
    // !!! Different meaning of rotation in Root than in Geant4
 
    experimentalHall_log->AddNode(
      calo_log, 1, new TGeoTranslation(Xpos, Ypos, Zpos));
 
    TGeoShape* crystal_box = new TGeoBBox(
      "Crystal", crystalWidth / 2, crystalWidth / 2, crystalLenght / 2);
    TGeoVolume* crystal_log =
      new TGeoVolume("Crystal_log", crystal_box, medPbWO4);
 
    for (Int_t i = 0; i < nbOfCrystals; i++) {
      for (Int_t j = 0; j < nbOfCrystals; j++) {
        Int_t n = i * nbOfCrystals + j;
 
        Double_t crystalPos_x = (i * crystalWidth) - 13.5;
        Double_t crystalPos_y = (j * crystalWidth) - 13.5;
        Double_t crystalPos_z = 0;
        calo_log->AddNode(crystal_log, n,
          new TGeoTranslation(crystalPos_x, crystalPos_y, crystalPos_z));
      }
    }
 
    // close geometry
    gGeoManager->CloseGeometry();
 
    // notify VMC about Root geometry
    gMC->SetRootGeometry();
 
    cout << "There are " << nbOfCrystals
         << " crystals per row in the calorimeter, so in total "
         << nbOfCrystals * nbOfCrystals << " crystals" << endl;
    cout << "The have width of " << crystalWidth << " cm and a lenght of "
         << crystalLenght << " cm. The Material is PbWO4" << endl;
  }

The documentation for this class was generated from the following files: