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Forum: Processes Involving Optical Photons
Date: 11 Sep, 2010
From: Davinder Siwal <Davinder Siwal>

Hiii GEANT4 Users

I am trying to simulate the detection efficirncy of BC501 scintillator detector

i have the neutrons as a primary particle and implemented HadronPhysicsLHEP_PRECO_HP physics process for interaction I am giving few lines of the proton recoils from the scintillator

*********************************************************************************************************
* G4Track Information:   Particle = proton,   Track ID = 6,   Parent ID = 1
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0      257     12.3    -16.5     0.383        0        0         0 NeutronDetector initStep
    1      257     12.3    -16.5         0    0.383  0.00368   0.00368 NeutronDetector hIoni
    2      257     12.3    -16.5         0        0        0   0.00368 NeutronDetector Scintillation

*********************************************************************************************************
* G4Track Information:   Particle = proton,   Track ID = 5,   Parent ID = 1
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0      244    -9.22     3.46     0.407        0        0         0 NeutronDetector initStep
    1      244    -9.22     3.46         0    0.407    0.004     0.004 NeutronDetector hIoni
    2      244    -9.22     3.46         0        0        0     0.004 NeutronDetector Scintillation

*********************************************************************************************************
* G4Track Information:   Particle = Mg24[0.0],   Track ID = 4,   Parent ID = 1
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0      241    -16.4     3.22     0.131        0        0         0 NeutronDetector initStep
    1      241    -16.4     3.22         0    0.131  0.00042   0.00042 NeutronDetector ionIoni
    2      241    -16.4     3.22         0        0        0   0.00042 NeutronDetector Scintillation

*********************************************************************************************************
* G4Track Information:   Particle = proton,   Track ID = 3,   Parent ID = 1
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0      239    -13.7     2.63     0.686        0        0         0 NeutronDetector initStep
    1      239    -13.7     2.62         0    0.686  0.00876   0.00876 NeutronDetector hIoni
    2      239    -13.7     2.62         0        0        0   0.00876 NeutronDetector Scintillation

*********************************************************************************************************
* G4Track Information:   Particle = proton,   Track ID = 2,   Parent ID = 1
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0      201        0        0     0.231        0        0         0 NeutronDetector initStep
    1      201  0.00177 -0.000339         0    0.231  0.00192   0.00192 NeutronDetector hIoni
    2      201  0.00177 -0.000339         0        0        0   0.00192 NeutronDetector Scintillation

but it does not giving any information about optical photons i am using the follwing physics list for optical process

#include "NdetOpticalPhysics.hh"
#include "G4Scintillation.hh"
#include "G4OpAbsorption.hh"
#include "G4OpRayleigh.hh"
#include "G4OpBoundaryProcess.hh"
#include "G4OpticalPhoton.hh"
#include "G4ProcessManager.hh"
#include <iomanip>
#include "globals.hh"

NdetOpticalPhysics::NdetOpticalPhysics(const G4String& name)
  : G4VPhysicsConstructor(name)
{
}

NdetOpticalPhysics::~NdetOpticalPhysics() {}

void NdetOpticalPhysics::ConstructProcess()
{
  ConstructOpticalProcess();
}
void NdetOpticalPhysics::ConstructOpticalProcess()
{
  theScintillationProcess = new G4Scintillation("Scintillation");
  theAbsorptionProcess = new G4OpAbsorption();
  theRayleighScatteringProcess = new G4OpRayleigh();
  theBoundaryProcess  = new G4OpBoundaryProcess();

  //-------- Set Verbosity 
  theScintillationProcess->SetVerboseLevel(1);
  theAbsorptionProcess->SetVerboseLevel(1);
  theRayleighScatteringProcess->SetVerboseLevel(1);
  theBoundaryProcess->SetVerboseLevel(1);
  //-----------------------

  G4ProcessManager* pManager = 0;
  pManager = G4OpticalPhoton::OpticalPhoton()->GetProcessManager();
  pManager->AddDiscreteProcess(theAbsorptionProcess);
  pManager->AddDiscreteProcess(theRayleighScatteringProcess);
  pManager->AddDiscreteProcess(theBoundaryProcess);

  theScintillationProcess->SetScintillationYieldFactor(1);
  theScintillationProcess->SetTrackSecondariesFirst(true);

   G4OpticalSurfaceModel themodel = unified;
  theBoundaryProcess->SetModel(themodel);

  theParticleIterator->reset();
  while( (*theParticleIterator)())
    {
   G4ParticleDefinition* particle = theParticleIterator->value();
   G4ProcessManager* pmanager = particle->GetProcessManager();
   //  G4String particleName = particle->GetParticleName();

   if (theScintillationProcess->IsApplicable(*particle)) 
     {
       pmanager->AddProcess(theScintillationProcess);
       pmanager->SetProcessOrderingToLast(theScintillationProcess, idxAtRest);
       pmanager->SetProcessOrderingToLast(theScintillationProcess, idxPostStep);
     }
    }
}

my detector has the follwing scintillation properties

const G4int nEntries = 2;
 double PhotonEnergy[nEntries] = {2.47*eV,3.09*eV};
 double RefractiveIndex[nEntries] = {1.538,1.538};
 double AbsLength[nEntries] = {4*m,4*m};

 G4MaterialPropertiesTable* myDet = new G4MaterialPropertiesTable();
 myDet->AddProperty("RINDEX", PhotonEnergy, RefractiveIndex, nEntries);
 myDet->AddProperty("ABSLENGTH", PhotonEnergy, AbsLength, nEntries);

 myDet->AddConstProperty("SCINTILLATIONYIELD",16000./MeV);
 myDet->AddConstProperty("DECAYTIME",3.3*ns);

 Scinti->SetMaterialPropertiesTable(myDet);

Here i didn't define the optical surface beacause of the following reason

i have confusion that does the optical surface works only at the surface ??

if this is so then what about the optical property of the main volume of

scintillator??? Or is there is any other reason that i am not getting any optical photons

Can Anybody help me in this situation

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1 None: Re: No Optical Photon is produced   (Randolph Moellenberg - 13 Sep, 2010)
1 None: Re: No Optical Photon is produced   (Davinder Siwal - 13 Sep, 2010)
(_ None: Re: No Optical Photon is produced   (Michael H. Kelsey - 13 Sep, 2010)
2 Feedback: Re: No Optical Photon is produced   (Gumplinger Peter - 14 Sep, 2010)
1 None: Re: No Optical Photon is produced   (Davinder Siwal - 15 Sep, 2010)
(_ Feedback: Re: No Optical Photon is produced   (Gumplinger Peter - 15 Sep, 2010)
(_ None: Re: No Optical Photon is produced   (Davinder Siwal - 15 Sep, 2010)
(_ None: Re: No Optical Photon is produced(Solved)   (Davinder Siwal - 20 Sep, 2010)
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