Dear experts,
I am working on a radiator, it functions as follows
It absorbs the incoming electrons and generates transition radiation photons (or gamma photons). But I am facing an issue, the energy of the gamma photons generated is very high, I am firing electrons of energy 3GeV and the energy of gamma photons generated is in the MeV to GeV range which in reality should be in 0-200 keV range. I have tried different EM modular physics list still the result remains the same, I also tried to set lower energy and higher energy limit for G4eBremsstrahlung, but still, the energy of gamma photons remains very high
I have attached an image of the output.
Radiator material:
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G4cout <<"G4Material* CH2 = "<<CH2<<G4endl;
G4cout <<"G4Material* Mylar = "<<Mylar<<G4endl;
G4double foilDensity = 0.91g/cm3; // CH2 1.39g/cm3; // Mylar // 0.534g/cm3; //Li
G4double gasDensity = 1.2928mg/cm3; // Air // 1.977mg/cm3; // CO2 0.178mg/cm3; // He
fRadThickness = 0.020mm;
fGasGap = 0.600mm;
fDetGap = 0.01*mm ;
foilGasRatio = fRadThickness/(fRadThickness+fGasGap);
G4cout<<"foil gas ratio is :- "<<foilGasRatio<<G4endl;
fRadThick = .3*cm - fGasGap + fDetGap;
fFoilNumber=fRadThick/(fRadThickness + fGasGap);
G4cout<<"The foil number is "<<fFoilNumber;
G4double totDensity = foilDensityfoilGasRatio + gasDensity(1.0-foilGasRatio) ;
G4cout<<"tot density is :- "<<totDensity<<G4endl;
G4cout<<"Rad totDensity = “<<totDensity/(g/cm3)<<” g/cm3 "<<G4endl ;
G4cout<<"use for Rad totDensity = “<<totDensity/(g/cm3)<<” g/cm3 "<<G4endl ;
G4double fractionFoil = foilDensityfoilGasRatio/totDensity ;
G4double fractionGas = gasDensity(1.0-foilGasRatio)/totDensity ;
G4cout<<"Fraction gas "<<fractionGas<<G4endl;
G4cout<<"Fraction foil "<<fractionFoil<<G4endl;
G4Material* radiatorMat0 = new G4Material(“radiatorMat0” , totDensity, 2);
radiatorMat0->AddMaterial( CH2, fractionFoil ) ;
radiatorMat0->AddMaterial( Air, fractionGas ) ;
G4double NewDensity = 0.083*(g/cm3);
G4Material* radiatorMat = new G4Material(“radiatorMat”,NewDensity,1);
radiatorMat->AddMaterial(radiatorMat0, 1.) ;
G4cout<<"new Rad with totDensity = “<<NewDensity/(g/cm3)<<” g/cm3 "<<G4endl ;
G4double XTR_density = radiatorMat->GetDensity();
G4cout<<"Read back Rad totDensity = “<<XTR_density/(g/cm3)<<” g/cm3 "<<G4endl ;
// default materials of the detector and TR radiator
fRadiatorMat = radiatorMat;
fFoilMat = CH2; // Kapton; // Mylar ; // Li ; // CH2 ;
fGasMat = Air; // CO2; // He; //
//Radiator
G4Box* solidEnv =
new G4Box(“Envelope”, //its name
7.5cm,7.5cm,7.5*cm); //its size
G4LogicalVolume* fLogicRadiator =
new G4LogicalVolume(solidEnv, //its solid
fRadiatorMat, //its material
“Envelope”); //its name
new G4PVPlacement(0, //no rotation
G4ThreeVector(0.,0.,7.5*cm), //at (0,0,0)
fLogicRadiator, //its logical volume
“Envelope”, //its name
logicWorld, //its mother volume
false, //no boolean operation
1, //copy number
checkOverlaps);
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Physics list – (Partial code)
else if (particleName == “e-”)
{
// Construct processes for electron
theeminusStepCut = new VtxStepCut();
theeminusStepCut->SetMaxStep(step_cut) ;
G4eIonisation* eioni = new G4eIonisation();
G4PAIModel* pai = new G4PAIModel(particle,"PAIModel");
eioni->AddEmModel(0,pai,pai,gas);
pmanager->AddProcess(new G4eMultipleScattering,-1,1,1);
pmanager->AddProcess(eioni,-1,2,2);
/*
G4eBremsstrahlung* msc = new G4eBremsstrahlung;
G4SeltzerBergerModel* msc1 = new G4SeltzerBergerModel();
G4eBremsstrahlungRelModel* msc2 = new G4eBremsstrahlungRelModel();
msc1->SetHighEnergyLimit(highEnergyLimit);
msc1->SetSecondaryThreshold(100*eV);
msc2->SetHighEnergyLimit(highEnergyLimit);
msc2->SetSecondaryThreshold(100*eV);
msc->AddEmModel(0, msc1);
msc->AddEmModel(0, msc2);
pmanager->AddProcess(msc,-1,3,3);*/
pmanager->AddProcess(new G4eBremsstrahlung,-1,3,3);
// pmanager->AddDiscreteProcess(processXTR);
pmanager->AddDiscreteProcess(new G4SynchrotronRadiation);
pmanager->AddDiscreteProcess(theeminusStepCut);
}
If someone wants to run the complete code. The following is the GitHub repository link :-
//https://github.com/nilay121/Radiator_GEMTRD
Kindly help me out with this, and thanks in advance.
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construction.cc (18.6 KB)
physics.cc (16.6 KB)
