simulating X-ray spectra from low energy electrons

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I am comparing the results of different Monte Carlo codes to simulate X-ray spectra from low energetic electrons (30 keV) impinging onto an infinitely thick slab of material.

The problem I have with GEANT4.9.2p02 is that the ratio of characteristic K X-ray line intensities to the bremsstrahlung continuum is too low when compared to experimental results. My target material is Copper (Cu) and the ratio is too low by a factor > 10+.

So my question is if this is "normal", because of the low energy/models, or have I done something wrong in my code? I have tried both the standard and low energy models, but the results don't differ much from each other.

Another, somewhat related, question is that for scoring the X-ray spectrum I store the X-ray energy and track weight:

G4Track* thisTrack = aStep->GetTrack();

G4double TrackWght = thisTrack->GetWeight();

G4double particleE = aStep->GetPreStepPoint()->GetKineticEnergy();

The track weight for the produced gamma's always seems to be 1.0 .. is that normal?

I am simulating a total of 100,000,000 histories to ensure decent statistics on the resulting X-ray spectra.

Any comments or suggestions are greatly appreciated,

Regards,

David

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

(1) The physicslist I am using is following (using the LowEnergy models):

--------------------------------------------------------------------------------------------

    if (particleName == "gamma") {
      // gamma

      G4LowEnergyPhotoElectric* LowPhotoElectric = new G4LowEnergyPhotoElectric();
      LowPhotoElectric->ActivateAuger(true);
      LowPhotoElectric->SetCutForLowEnSecPhotons(1.0*keV);
      LowPhotoElectric->SetCutForLowEnSecElectrons(1.0*keV);

      pmanager->AddDiscreteProcess(LowPhotoElectric);
      pmanager->AddDiscreteProcess(new G4LowEnergyCompton());
      pmanager->AddDiscreteProcess(new G4LowEnergyRayleigh());

    } else if (particleName == "e-") {
      //electron

      G4LowEnergyIonisation* LowIonProcess = new G4LowEnergyIonisation("IONI");
      LowIonProcess->ActivateAuger(true);
      LowIonProcess->SetCutForLowEnSecPhotons(1.0*keV);
      LowIonProcess->SetCutForLowEnSecElectrons(1.0*keV);

      pmanager->AddProcess(new G4MultipleScattering,-1, 1,1);
      pmanager->AddProcess(LowIonProcess, -1, 2, 2);
      pmanager->AddProcess(new G4LowEnergyBremsstrahlung, -1, -1, 3);

    } else if (particleName == "e+") {
      //positron
      pmanager->AddProcess(new G4MultipleScattering,-1, 1,1);
      pmanager->AddProcess(new G4eIonisation,       -1, 2,2);
      pmanager->AddProcess(new G4eBremsstrahlung,   -1, 3,3);
      pmanager->AddProcess(new G4eplusAnnihilation,  0,-1,4);
    }

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(2) I have set the cuts for electrons and gammas to 10nm

  SetCutValue(10*nm, "gamma");
  SetCutValue(10*nm, "e-");

--------------------------------------------------------------------------------------------

(3) The target material is defined as:

  G4Material*   Cu = new G4Material("Copper",Z=29, A=63.54*g/mole, 8.92*g/cm3);

--------------------------------------------------------------------------------------------

(4) The gun has following definition:

  G4int n_particle = 1;
  particleGun = new G4ParticleGun(n_particle);

  G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
  G4ParticleDefinition* particle = particleTable->FindParticle("e-");

  particleGun->SetParticleDefinition(particle);
  particleGun->SetParticleEnergy(30.0*keV);
  particleGun->SetParticlePosition(G4ThreeVector(0*cm, 0*cm, 15*cm));
  particleGun->SetParticleMomentumDirection(G4ThreeVector(0,0,-1));

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