Message: The problem of Cherenkov photons Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

None The problem of Cherenkov photons 

Forum: Particles
Date: 28 Nov, 2013
From: yanxin0221 <yanxin0221>

Hi everyone,
  I'm new with geant4.The numbers of Cherenkov photon in the PMMA are more than in the water from N= (2*z^2)/137 *sin^2 *(1/_2 -1/_1 ). However, the results simulated are reversed in the spectra of Cherenkov photons in the PMMA and water.
  Could you give me some idea or advices to solve this problem? Thanks a lot everybody. yours sincerely, Yanxin.
Here is my DetectorConstruction.cc:

#include "EADetectorConstruction.hh"

#include "G4Material.hh"
#include "G4Element.hh"
#include "G4LogicalBorderSurface.hh"
#include "G4LogicalSkinSurface.hh"
#include "G4OpticalSurface.hh"
#include "G4Box.hh"
#include "G4LogicalVolume.hh"
#include "G4ThreeVector.hh"
#include "G4PVPlacement.hh"
#include "G4SystemOfUnits.hh"
#include "G4Tubs.hh"

#include "G4Orb.hh"
#include "G4PVReplica.hh"
#include "G4SolidStore.hh"
#include "G4NistManager.hh"
#include "globals.hh"

#include "G4VisAttributes.hh"
#include "G4Colour.hh"

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

EADetectorConstruction::EADetectorConstruction()
 :  expHall_log(0), waterTank_log(0),
    expHall_phys(0) ,waterTank_phys(0)
{
   for(int j=0;j<87;j++)
     { tubedetectorl[j] =0;
       tubedetectorp[j] =0;
      }
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

EADetectorConstruction::~EADetectorConstruction(){;}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

G4VPhysicalVolume* EADetectorConstruction::Construct() {

// ------------- Materials -------------

  G4double a, z, density;
  G4int nelements;
  G4double expHall_x = 400.0*cm;
  G4double expHall_y = 400.0*cm;
  G4double expHall_z = 40.0*cm;
  G4double tank_x  =  350.0*cm;
  G4double tank_y  =  350.0*cm;
  G4double tank_z  =  35.0*cm;
// Air
// 
  G4Element* N = new G4Element("Nitrogen", "N", z=7 , a=14.01*g/mole);
  G4Element* O = new G4Element("Oxygen"  , "O", z=8 , a=16.00*g/mole);

  G4Material* Air = new G4Material("Air", density=1.29*mg/cm3, nelements=2);
  Air->AddElement(N, 70.*perCent);
  Air->AddElement(O, 30.*perCent);

// Water
// 
  G4Element* H = new G4Element("Hydrogen", "H", z=1 , a=1.01*g/mole);

  G4Material* Water = new G4Material("Water", density= 1.0*g/cm3, nelements=2);
  Water->AddElement(H, 2);
  Water->AddElement(O, 1);

//
// ------------ Generate & Add Material Properties Table ------------
//
  const G4int nEntries = 32;

  G4double PhotonEnergy[nEntries] =
            { 2.034*eV, 2.068*eV, 2.103*eV, 2.139*eV,
              2.177*eV, 2.216*eV, 2.256*eV, 2.298*eV,
              2.341*eV, 2.386*eV, 2.433*eV, 2.481*eV,
              2.532*eV, 2.585*eV, 2.640*eV, 2.697*eV,
              2.757*eV, 2.820*eV, 2.885*eV, 2.954*eV,
              3.026*eV, 3.102*eV, 3.181*eV, 3.265*eV,
              3.353*eV, 3.446*eV, 3.545*eV, 3.649*eV,
              3.760*eV, 3.877*eV, 4.002*eV, 4.136*eV };
//
// Water
//              
  G4double RefractiveIndex1[nEntries] =
            { 1.3435, 1.344,  1.3445, 1.345,  1.3455,
              1.346,  1.3465, 1.347,  1.3475, 1.348,
              1.3485, 1.3492, 1.35,   1.3505, 1.351,
              1.3518, 1.3522, 1.3530, 1.3535, 1.354,
              1.3545, 1.355,  1.3555, 1.356,  1.3568,
              1.3572, 1.358,  1.3585, 1.359,  1.3595,
              1.36,   1.3608};

  G4double Absorption1[nEntries] =
           {3.448*m,  4.082*m,  6.329*m,  9.174*m, 12.346*m, 13.889*m,
           15.152*m, 17.241*m, 18.868*m, 20.000*m, 26.316*m, 35.714*m,
           45.455*m, 47.619*m, 52.632*m, 52.632*m, 55.556*m, 52.632*m,
           52.632*m, 47.619*m, 45.455*m, 41.667*m, 37.037*m, 33.333*m,
           30.000*m, 28.500*m, 27.000*m, 24.500*m, 22.000*m, 19.500*m,
           17.500*m, 14.500*m };

  G4double ScintilFast[nEntries] =
            { 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00,
              1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00,
              1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00,
              1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00,
              1.00, 1.00, 1.00, 1.00 };
  G4double ScintilSlow[nEntries] =
            { 0.01, 1.00, 2.00, 3.00, 4.00, 5.00, 6.00,
              7.00, 8.00, 9.00, 8.00, 7.00, 6.00, 4.00,
              3.00, 2.00, 1.00, 0.01, 1.00, 2.00, 3.00,
              4.00, 5.00, 6.00, 7.00, 8.00, 9.00, 8.00,
              7.00, 6.00, 5.00, 4.00 };

  G4MaterialPropertiesTable* myMPT1 = new G4MaterialPropertiesTable();

  myMPT1->AddProperty("RINDEX",       PhotonEnergy, RefractiveIndex1,nEntries)
        ->SetSpline(true);
  myMPT1->AddProperty("ABSLENGTH",    PhotonEnergy, Absorption1,     nEntries)
        ->SetSpline(true);
  myMPT1->AddProperty("FASTCOMPONENT",PhotonEnergy, ScintilFast,     nEntries)
        ->SetSpline(true);
  myMPT1->AddProperty("SLOWCOMPONENT",PhotonEnergy, ScintilSlow,     nEntries)
        ->SetSpline(true);

  myMPT1->AddConstProperty("SCINTILLATIONYIELD",50./MeV);
  myMPT1->AddConstProperty("RESOLUTIONSCALE",1.0);
  myMPT1->AddConstProperty("FASTTIMECONSTANT", 1.*ns);
  myMPT1->AddConstProperty("SLOWTIMECONSTANT",10.*ns);
  myMPT1->AddConstProperty("YIELDRATIO",0.8);

  const G4int NUMENTRIES_water = 60;

  G4double ENERGY_water[NUMENTRIES_water] = {
     1.56962*eV, 1.58974*eV, 1.61039*eV, 1.63157*eV,
     1.65333*eV, 1.67567*eV, 1.69863*eV, 1.72222*eV,
     1.74647*eV, 1.77142*eV, 1.7971 *eV, 1.82352*eV,
     1.85074*eV, 1.87878*eV, 1.90769*eV, 1.93749*eV,
     1.96825*eV, 1.99999*eV, 2.03278*eV, 2.06666*eV,
     2.10169*eV, 2.13793*eV, 2.17543*eV, 2.21428*eV,
     2.25454*eV, 2.29629*eV, 2.33962*eV, 2.38461*eV,
     2.43137*eV, 2.47999*eV, 2.53061*eV, 2.58333*eV,
     2.63829*eV, 2.69565*eV, 2.75555*eV, 2.81817*eV,
     2.88371*eV, 2.95237*eV, 3.02438*eV, 3.09999*eV,
     3.17948*eV, 3.26315*eV, 3.35134*eV, 3.44444*eV,
     3.54285*eV, 3.64705*eV, 3.75757*eV, 3.87499*eV,
     3.99999*eV, 4.13332*eV, 4.27585*eV, 4.42856*eV,
     4.59258*eV, 4.76922*eV, 4.95999*eV, 5.16665*eV,
     5.39129*eV, 5.63635*eV, 5.90475*eV, 6.19998*eV
  };

  //assume 100 times larger than the rayleigh scattering for now.
  G4double MIE_water[NUMENTRIES_water] = {
     167024.4*m, 158726.7*m, 150742  *m,
     143062.5*m, 135680.2*m, 128587.4*m,
     121776.3*m, 115239.5*m, 108969.5*m,
     102958.8*m, 97200.35*m, 91686.86*m,
     86411.33*m, 81366.79*m, 76546.42*m,
     71943.46*m, 67551.29*m, 63363.36*m,
     59373.25*m, 55574.61*m, 51961.24*m,
     48527.00*m, 45265.87*m, 42171.94*m,
     39239.39*m, 36462.50*m, 33835.68*m,
     31353.41*m, 29010.30*m, 26801.03*m,
     24720.42*m, 22763.36*m, 20924.88*m,
     19200.07*m, 17584.16*m, 16072.45*m,
     14660.38*m, 13343.46*m, 12117.33*m,
     10977.70*m, 9920.416*m, 8941.407*m,
     8036.711*m, 7202.470*m, 6434.927*m,
     5730.429*m, 5085.425*m, 4496.467*m,
     3960.210*m, 3473.413*m, 3032.937*m,
     2635.746*m, 2278.907*m, 1959.588*m,
     1675.064*m, 1422.710*m, 1200.004*m,
     1004.528*m, 833.9666*m, 686.1063*m
  };

  // gforward, gbackward, forward backward ratio
  G4double MIE_water_const[3]={0.99,0.99,0.8};

  myMPT1->AddProperty("MIEHG",ENERGY_water,MIE_water,NUMENTRIES_water)
        ->SetSpline(true);
  myMPT1->AddConstProperty("MIEHG_FORWARD",MIE_water_const[0]);
  myMPT1->AddConstProperty("MIEHG_BACKWARD",MIE_water_const[1]);
  myMPT1->AddConstProperty("MIEHG_FORWARD_RATIO",MIE_water_const[2]);

  Water->SetMaterialPropertiesTable(myMPT1);

  // Set the Birks Constant for the Water scintillator

  Water->GetIonisation()->SetBirksConstant(0.126*mm/MeV);

//
// Air
//
  G4double RefractiveIndex2[nEntries] =
            { 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00,
              1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00,
              1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00,
              1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00,
              1.00, 1.00, 1.00, 1.00 };

  G4MaterialPropertiesTable* myMPT2 = new G4MaterialPropertiesTable();
  myMPT2->AddProperty("RINDEX", PhotonEnergy, RefractiveIndex2, nEntries);

  Air->SetMaterialPropertiesTable(myMPT2);

// // ------------- Volumes --------------

// The experimental Hall
//
  G4Box* expHall_box = new G4Box("World",expHall_x,expHall_y,expHall_z);
expHall_log = new G4LogicalVolume(expHall_box,Air,"World",0,0,0);

expHall_phys = new G4PVPlacement(0,G4ThreeVector(),expHall_log,"World",0,false,0);

// The Water Tank
//        
  G4Box* waterTank_box = new G4Box("Tank",tank_x,tank_y,tank_z);

waterTank_log = new G4LogicalVolume(waterTank_box,Water,"Tank",0,0,0);

  waterTank_phys = new G4PVPlacement(0,G4ThreeVector(),waterTank_log,"Tank",
                        expHall_log,false,0);

G4double x;
G4double y;
G4int i;
for(int j=0;j<87;j++)
{
 ; 
 i=j+1;
 //n=i*0.1;
 x=tan(j*3.1415926/180)*20;
 y=tan(i*3.1415926/180)*20;

//G4cout << "x="<<x<<"\t" <<"y="<< y <<"\t"<<G4endl;
G4Tubs* tracker_tube = new G4Tubs("tracker_tube",x*cm,
                                   y*cm,50*nm,
                                    0.*deg,360.*deg);

tubedetectorl[j] = new G4LogicalVolume(tracker_tube,Air,"tubedetectorl",0,0,0);
tubedetectorp[j] = new G4PVPlacement(0,
            G4ThreeVector(0,0,20*cm),
             tubedetectorl[j],"tubeDetector",waterTank_log,false,0);

 G4VisAttributes*  tubedetectorlVisAtt
    = new  G4VisAttributes(G4Colour(1.0,1.0,1.0));

 tubedetectorl[j] ->SetVisAttributes(tubedetectorlVisAtt);

  G4VisAttributes* expHall_logVisAtt= new G4VisAttributes(G4Colour(1.0,1.0,1.0));
  expHall_log ->SetVisAttributes(expHall_logVisAtt); 
  G4VisAttributes* waterTank_logVisAtt= new G4VisAttributes(G4Colour(1.0,0.0,1.0));
  waterTank_log ->SetVisAttributes(waterTank_logVisAtt); 
 // Water Tank
//
  G4OpticalSurface* OpWaterSurface = new G4OpticalSurface("WaterSurface");
  OpWaterSurface->SetType(dielectric_metal);
  OpWaterSurface->SetFinish(polished);
  OpWaterSurface->SetModel(glisur);

  new G4LogicalBorderSurface("WaterSurface",
                                 waterTank_phys,expHall_phys,OpWaterSurface);

// Air Bubble
//
  G4OpticalSurface* OpAirSurface = new G4OpticalSurface("AirSurface");
  OpAirSurface->SetType(dielectric_metal);
  OpAirSurface->SetFinish(polished);
  OpAirSurface->SetModel(glisur);

  G4LogicalSkinSurface* AirSurface = 
          new G4LogicalSkinSurface("AirSurface", tubedetectorl[j], OpAirSurface);

  G4OpticalSurface* opticalSurface = dynamic_cast <G4OpticalSurface*>
        (AirSurface->GetSurface(tubedetectorl[j])->GetSurfaceProperty());

  if (opticalSurface) opticalSurface->DumpInfo();

// Generate & Add Material Properties Table attached to the optical surfaces
//
  const G4int num = 2;
  G4double Ephoton[num] = {2.034*eV, 4.136*eV};

  //OpticalWaterSurface 

  G4double Reflectivity[num] = {0.0, 0.0};
  G4double Efficiency[num]   = {1.0, 1.0};

  G4MaterialPropertiesTable* myST1 = new G4MaterialPropertiesTable();

  myST1->AddProperty("REFLECTIVITY", Ephoton, Reflectivity, num);
  myST1->AddProperty("EFFICIENCY",   Ephoton, Efficiency,    num);

  OpWaterSurface->SetMaterialPropertiesTable(myST1);

  G4MaterialPropertiesTable *myST2 = new G4MaterialPropertiesTable();

  myST2->AddProperty("REFLECTIVITY", Ephoton, Reflectivity, num);
  myST2->AddProperty("EFFICIENCY",   Ephoton, Efficiency,   num);
  OpAirSurface->SetMaterialPropertiesTable(myST2);
};
//always return the physical World
  return expHall_phys;
}

 Add Message Add Message
to: "The problem of Cherenkov photons"

 Subscribe Subscribe

This site runs SLAC HyperNews version 1.11-slac-98, derived from the original HyperNews


[ Geant 4 Home | Geant 4 HyperNews | Search | Request New Forum | Feedback ]