DetectorConstruction.cxx

Go to the documentation of this file.

//------------------------------------------------
// The Virtual Monte Carlo examples
// Copyright (C) 2007 - 2016 Ivana Hrivnacova
// All rights reserved.
//
// For the licensing terms see geant4_vmc/LICENSE.
// Contact: root-vmc@cern.ch
//-------------------------------------------------
 
/// \file ExGarfield/src/DetectorConstruction.cxx
/// \brief Implementation of the ExGarfield::DetectorConstruction class
///
/// Garfield garfieldpp example adapted to Virtual Monte Carlo.
///
/// \date 28/10/2015
/// \author I. Hrivnacova; IPN, Orsay
 
#include <Riostream.h>
#include <TGeoBBox.h>
#include <TGeoElement.h>
#include <TGeoManager.h>
#include <TGeoMaterial.h>
#include <TGeoTube.h>
#include <TGeoVolume.h>
#include <TList.h>
#include <TThread.h>
#include <TVirtualMC.h>
 
#include "DetectorConstruction.h"
 
using namespace std;
 
/// \cond CLASSIMP
ClassImp(VMC::ExGarfield::DetectorConstruction)
  /// \endcond
 
  namespace VMC
{
  namespace ExGarfield
  {
 
  //_____________________________________________________________________________
  DetectorConstruction::DetectorConstruction() : TObject()
  {
    /// Default constuctor
  }
 
  //_____________________________________________________________________________
  DetectorConstruction::~DetectorConstruction()
  {
    /// Destructor
  }
 
  //
  // public methods
  //
 
  //_____________________________________________________________________________
  void DetectorConstruction::Construct()
  {
    /// Construct geometry using TGeo modeller
 
    // Create Root geometry manager
    new TGeoManager("Garfield_geometry", "ExGarfield VMC example geometry");
 
    // Elements
    //
    Double_t z, a;
    TGeoElement* elH = new TGeoElement("Hydrogen", "H", z = 1., a = 1.01);
    TGeoElement* elC = new TGeoElement("Carbon", "C", z = 6., a = 12.01);
    TGeoElement* elN = new TGeoElement("Nitrogen", "N", z = 7., a = 14.01);
    TGeoElement* elO = new TGeoElement("Oxygen", "O", z = 8., a = 16.00);
    TGeoElement* elAr = new TGeoElement("Argon", "Ar", z = 18., a = 39.94);
    // TGeoElement* elW  = new TGeoElement("Tungsten", "W",  z = 74., a =
    // 183.84); TGeoElement* elPb = new TGeoElement("Lead",     "Pb", z = 82., a
    // = 207.22);
 
    // Materials
    //
 
    // Al
    Double_t density;
    TGeoMaterial* matAl =
      new TGeoMaterial("Al", a = 26.98, z = 13., density = 2.699);
 
    // W
    TGeoMaterial* matW =
      new TGeoMaterial("Tungsten", a = 183.85, z = 74., density = 19.30);
 
    // Pb
    TGeoMaterial* matPb =
      new TGeoMaterial("Lead", a = 207.22, z = 82., density = 11.35);
 
    // Air
    TGeoMixture* matAir = new TGeoMixture("AirA", 4, density = 1.205e-03);
    matAir->AddElement(elC, 0.0001);
    matAir->AddElement(elN, 0.7553);
    matAir->AddElement(elO, 0.2318);
    matAir->AddElement(elAr, 0.0128);
 
    // ArCO2_70_30
    TGeoMixture* matArCO2 = new TGeoMixture("ArCO2", 3, density = 1.822e-03);
    matArCO2->AddElement(elAr, 0.7000);
    matArCO2->AddElement(elC, 0.0819);
    matArCO2->AddElement(elO, 0.2181);
 
    // Kapton
    TGeoMixture* matKapton = new TGeoMixture("Kapton", 4, density = 1.413);
    matKapton->AddElement(elO, 0.2092);
    matKapton->AddElement(elC, 0.6911);
    matKapton->AddElement(elN, 0.0733);
    matKapton->AddElement(elH, 0.0264);
 
    // 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* medAl = new TGeoMedium("Al", ++mediumId, matAl, param);
    TGeoMedium* medW = new TGeoMedium("W", ++mediumId, matW, param);
    TGeoMedium* medPb = new TGeoMedium("Pb", ++mediumId, matPb, param);
    TGeoMedium* medAir = new TGeoMedium("AirA", ++mediumId, matAir, param);
    TGeoMedium* medArCO2 = new TGeoMedium("ArCO2", ++mediumId, matArCO2, param);
 
    TGeoMedium* defaultMedium = medAir;
    TGeoMedium* absorberMedium = medPb;
    TGeoMedium* gasMedium = medArCO2;
    TGeoMedium* cathodeMedium = medAl;
    TGeoMedium* wireMedium = medW;
 
    // Volumes
    //
 
    // Geometry parameters
    Double_t mm = 0.1;   // milimeter -> cm
    Double_t um = 1.e-4; // micrometer -> cm
    Double_t worldSizeXYZ = 1000 * mm;
    Double_t absorberThicknessZ = 10. * mm;
    Double_t absorberThicknessXY = 100. * mm;
    Double_t wireRadius = 0.025 * mm;
    Double_t tubeRadius = 15 * mm;
    Double_t tubeHalfLength = 100 * mm;
    Double_t tubeThickness = 500 * um;
 
    //
    // World
    //
    TGeoShape* worldS = new TGeoBBox("World", // its name
      0.5 * worldSizeXYZ, 0.5 * worldSizeXYZ,
      0.5 * worldSizeXYZ); // its size
 
    TGeoVolume* worldLV = new TGeoVolume("World", worldS, defaultMedium);
 
    gGeoManager->SetTopVolume(worldLV);
 
    //
    // Absorber
    //
    TGeoShape* absorberS = new TGeoBBox("Absorber", // its name
      0.5 * absorberThicknessXY, 0.5 * absorberThicknessXY,
      0.5 * absorberThicknessZ); // its size
 
    TGeoVolume* absorberLV =
      new TGeoVolume("Absorber", absorberS, absorberMedium);
 
    Double_t xpos = 0;
    Double_t ypos = 0;
    Double_t zpos = absorberThicknessZ / 2;
    worldLV->AddNode(absorberLV, 1, new TGeoTranslation(xpos, ypos, zpos));
 
    //
    // Drift tube
    //
    TGeoShape* tubeS =
      new TGeoTube("Tube", 0, tubeRadius, tubeHalfLength + tubeThickness);
 
    TGeoVolume* tubeLV = new TGeoVolume("Tube", tubeS, cathodeMedium);
 
    TGeoRotation* rotY = new TGeoRotation();
    rotY->RotateY(-90.);
    ypos = -0.2 * tubeRadius;
    zpos = absorberThicknessZ + tubeRadius;
    worldLV->AddNode(tubeLV, 1, new TGeoCombiTrans(xpos, ypos, zpos, rotY));
 
    //
    // Drift Tube Gas
    //
    TGeoShape* gasS = new TGeoTube(
      "Gas", wireRadius, tubeRadius - tubeThickness, tubeHalfLength);
 
    TGeoVolume* gasLV = new TGeoVolume("Gas", gasS, gasMedium);
 
    ypos = 0.;
    zpos = 0.;
    tubeLV->AddNode(gasLV, 1, new TGeoTranslation(xpos, ypos, zpos));
 
    //
    // Wire
    //
    TGeoShape* wireS = new TGeoTube("Wire", 0, wireRadius, tubeHalfLength);
 
    TGeoVolume* wireLV = new TGeoVolume("Wire", wireS, wireMedium);
 
    ypos = 0.;
    zpos = 0.;
    tubeLV->AddNode(wireLV, 1, new TGeoTranslation(xpos, ypos, zpos));
 
    // close geometry
    gGeoManager->CloseGeometry();
 
    // write geometry
    gGeoManager->Export("geometry.root");
 
    // notify VMC about Root geometry
    gMC->SetRootGeometry();
  }
 
  } // namespace ExGarfield
}