Import Geant4 3.0.0 source tree
This commit is contained in:
Gabriele Cosmo
@@ -1,459 +0,0 @@
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// This code implementation is the intellectual property of
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// the GEANT4 collaboration.
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//
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// By copying, distributing or modifying the Program (or any work
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// based on the Program) you indicate your acceptance of this statement,
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// and all its terms.
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//
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// $Id: G4ionIonisation.cc,v 1.4 1999/12/15 14:51:54 gunter Exp $
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// GEANT4 tag $Name: geant4-02-00 $
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//
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// -------------------------------------------------------------
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// GEANT 4 class implementation file
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//
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// For information related to this code contact:
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// CERN, IT Division, ASD group
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// History: based on object model of
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// 2nd December 1995, G.Cosmo
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// ---------- G4ionIonisation physics process -----------
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// by Laszlo Urban, 08 Dec 1998
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// **************************************************************
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// It is the first implementation of the ionisation for IONS
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// --------------------------------------------------------------
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#include "G4ionIonisation.hh"
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#include "G4UnitsTable.hh"
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// constructor and destructor
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G4ionIonisation::G4ionIonisation(const G4String& processName)
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: G4VContinuousDiscreteProcess(processName),
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ParticleMass(proton_mass_c2),Charge(eplus),
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dEdx(1.*MeV/mm),MinKineticEnergy(1.*keV)
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{ PrintInfoDefinition() ; }
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G4ionIonisation::~G4ionIonisation()
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{ }
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G4double G4ionIonisation::GetConstraints(const G4DynamicParticle *aParticle,
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G4Material *aMaterial)
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{
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// returns the Step limit
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// dRoverRange is the max. allowed relative range loss in one step
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// it calculates dEdx and the range as well....
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const G4double minstep=0.01*mm ;
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G4double KineticEnergy,StepLimit;
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Charge = aParticle->GetDefinition()->GetPDGCharge()/eplus ;
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KineticEnergy = aParticle->GetKineticEnergy();
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G4double massratio=proton_mass_c2/
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aParticle->GetDefinition()->GetPDGMass() ;
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G4double Tscaled= KineticEnergy*massratio ;
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G4double ChargeSquare = Charge*Charge ;
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dEdx=ComputedEdx(aParticle,aMaterial) ;
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StepLimit = 0.2*KineticEnergy/dEdx ;
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if(StepLimit < minstep)
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StepLimit = minstep ;
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return StepLimit ;
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}
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G4VParticleChange* G4ionIonisation::AlongStepDoIt(
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const G4Track& trackData,const G4Step& stepData)
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// compute the energy loss after a step
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{
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const G4DynamicParticle* aParticle;
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G4Material* aMaterial;
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G4double E,finalT,Step,ChargeSquare,MeanLoss ;
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aParticleChange.Initialize(trackData) ;
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aMaterial = trackData.GetMaterial() ;
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// get the actual (true) Step length from stepData
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Step = stepData.GetStepLength() ;
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aParticle = trackData.GetDynamicParticle() ;
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G4double massratio=proton_mass_c2/
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aParticle->GetDefinition()->GetPDGMass() ;
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ChargeSquare = Charge*Charge ;
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G4int index = aMaterial->GetIndex() ;
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E = aParticle->GetKineticEnergy() ;
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if(E < MinKineticEnergy) MeanLoss = E ;
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else
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{
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MeanLoss = Step*dEdx ;
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MeanLoss /= (massratio*ChargeSquare) ;
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}
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finalT = E - MeanLoss ;
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if(finalT < MinKineticEnergy) finalT = 0. ;
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// kill the particle if the kinetic energy <= 0
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if (finalT <= 0. )
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{
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finalT = 0.;
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aParticleChange.SetStatusChange(fStopAndKill);
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}
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aParticleChange.SetEnergyChange( finalT ) ;
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aParticleChange.SetLocalEnergyDeposit(E-finalT) ;
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return &aParticleChange ;
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}
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G4double G4ionIonisation::GetMeanFreePath(
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const G4Track& trackData,
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G4double previousStepSize,
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G4ForceCondition* condition)
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{
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const G4DynamicParticle* aParticle ;
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G4Material* aMaterial ;
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G4double MeanFreePath;
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*condition = NotForced ;
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aParticle = trackData.GetDynamicParticle() ;
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aMaterial = trackData.GetMaterial() ;
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G4double KineticEnergy = aParticle->GetKineticEnergy() ;
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Charge=(aParticle->GetDefinition()->GetPDGCharge())/eplus;
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G4double ChargeSquare=Charge*Charge ;
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// compute the (macroscopic) cross section first
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const G4ElementVector* theElementVector=
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aMaterial->GetElementVector() ;
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const G4double* theAtomicNumDensityVector =
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aMaterial->GetAtomicNumDensityVector();
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const G4int NumberOfElements=
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aMaterial->GetNumberOfElements() ;
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G4int index = aMaterial->GetIndex() ;
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DeltaCutInKineticEnergy = G4Electron::Electron()->GetCutsInEnergy();
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DeltaCutInKineticEnergyNow = DeltaCutInKineticEnergy[index] ;
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G4double sigma = 0. ;
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for (G4int iel=0; iel<NumberOfElements; iel++ )
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{
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sigma += theAtomicNumDensityVector[iel]*
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ComputeMicroscopicCrossSection(aParticle,
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KineticEnergy,
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(*theElementVector)(iel)->GetZ() ) ;
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}
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sigma *= twopi_mc2_rcl2 * ChargeSquare ;
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// mean free path = 1./macroscopic cross section
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MeanFreePath = sigma<=0 ? DBL_MAX : 1./sigma ;
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return MeanFreePath ;
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}
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G4double G4ionIonisation::ComputeMicroscopicCrossSection(
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const G4DynamicParticle* aParticle,
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G4double KineticEnergy,
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G4double AtomicNumber)
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{
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G4double TotalEnergy,
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betasquare,
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MaxKineticEnergyTransfer,TotalCrossSection,tempvar;
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// get particle data ...................................
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ParticleMass = aParticle->GetDefinition()->GetPDGMass() ;
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TotalEnergy=KineticEnergy + ParticleMass;
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// some kinematics......................
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betasquare = KineticEnergy*(TotalEnergy+ParticleMass)
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/(TotalEnergy*TotalEnergy);
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tempvar = ParticleMass+electron_mass_c2;
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MaxKineticEnergyTransfer = 2.*electron_mass_c2*KineticEnergy
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*(TotalEnergy+ParticleMass)
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/(tempvar*tempvar+2.*electron_mass_c2*KineticEnergy);
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// now you can calculate the total cross section ------------------
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if( MaxKineticEnergyTransfer > DeltaCutInKineticEnergyNow )
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{
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tempvar=DeltaCutInKineticEnergyNow/MaxKineticEnergyTransfer;
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TotalCrossSection = (1.-tempvar*(1.-betasquare*log(tempvar)))
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/DeltaCutInKineticEnergyNow;
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TotalCrossSection *= AtomicNumber/betasquare;
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}
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else
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TotalCrossSection= 0. ;
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return TotalCrossSection ;
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}
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G4double G4ionIonisation::ComputedEdx(const G4DynamicParticle* aParticle,
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G4Material* material)
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{
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// cuts for electron ....................
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DeltaCutInKineticEnergy = G4Electron::Electron()->GetCutsInEnergy() ;
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G4double KineticEnergy , ionloss ;
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G4double RateMass ;
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G4bool isOutRange ;
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const G4double twoln10 = 2.*log(10.) ;
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const G4double Factor = twopi_mc2_rcl2 ;
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const G4double bg2lim = 0.0169 , taulim = 8.4146e-3 ;
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RateMass = electron_mass_c2/proton_mass_c2 ;
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// get material parameters needed for the energy loss calculation
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G4double ElectronDensity,Eexc,Eexc2,Cden,Mden,Aden,X0den,X1den,taul ;
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G4double* ShellCorrectionVector;
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ElectronDensity = material->GetElectronDensity();
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Eexc = material->GetIonisation()->GetMeanExcitationEnergy();
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Eexc2 = Eexc*Eexc ;
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Cden = material->GetIonisation()->GetCdensity();
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Mden = material->GetIonisation()->GetMdensity();
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Aden = material->GetIonisation()->GetAdensity();
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X0den = material->GetIonisation()->GetX0density();
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X1den = material->GetIonisation()->GetX1density();
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taul = material->GetIonisation()->GetTaul() ;
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ShellCorrectionVector = material->GetIonisation()->
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GetShellCorrectionVector();
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// get elements in the actual material,
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// they are needed for the low energy part ....
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const G4ElementVector* theElementVector=
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material->GetElementVector() ;
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const G4double* theAtomicNumDensityVector=
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material->GetAtomicNumDensityVector() ;
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const G4int NumberOfElements=
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material->GetNumberOfElements() ;
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// get electron cut in kin. energy for the material
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DeltaCutInKineticEnergyNow =
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DeltaCutInKineticEnergy[material->GetIndex()] ;
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// some local variables -------------------
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G4double tau,tau0,Tmax,gamma,bg2,beta2,rcut,delta,x,sh ;
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KineticEnergy=aParticle->GetKineticEnergy();
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tau = KineticEnergy/proton_mass_c2 ;
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if ( tau < taul )
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// low energy part , parametrized energy loss formulae
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{
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ionloss = 0. ;
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// loop for the elements in the material
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for (G4int iel=0; iel<NumberOfElements; iel++)
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{
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const G4Element* element = (*theElementVector)(iel);
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if ( tau < element->GetIonisation()->GetTau0())
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ionloss += theAtomicNumDensityVector[iel]
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*( element->GetIonisation()->GetAlow()*sqrt(tau)
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+element->GetIonisation()->GetBlow()*tau) ;
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else
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ionloss += theAtomicNumDensityVector[iel]
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* element->GetIonisation()->GetClow()/sqrt(tau) ;
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}
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}
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else
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// high energy part , Bethe-Bloch formula
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{
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gamma = tau +1. ;
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bg2 = tau*(tau+2.) ;
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beta2 = bg2/(gamma*gamma) ;
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Tmax = 2.*electron_mass_c2*bg2
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/(1.+2.*gamma*RateMass+RateMass*RateMass) ;
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if ( DeltaCutInKineticEnergyNow < Tmax)
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rcut = DeltaCutInKineticEnergyNow/Tmax ;
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else
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rcut = 1.;
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ionloss = log(2.*electron_mass_c2*bg2*Tmax/Eexc2)
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+log(rcut)-(1.+rcut)*beta2 ;
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// density correction
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x = log(bg2)/twoln10 ;
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if ( x < X0den )
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delta = 0. ;
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else
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{
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delta = twoln10*x - Cden ;
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if ( x < X1den )
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delta += Aden*pow((X1den-x),Mden) ;
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}
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// shell correction
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if ( bg2 > bg2lim ) {
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sh = 0. ;
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x = 1. ;
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for (G4int k=0; k<=2; k++) {
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x *= bg2 ;
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sh += ShellCorrectionVector[k]/x;
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}
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}
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else {
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sh = 0. ;
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x = 1. ;
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for (G4int k=0; k<=2; k++) {
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x *= bg2lim ;
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sh += ShellCorrectionVector[k]/x;
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}
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sh *= log(tau/taul)/log(taulim/taul) ;
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}
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// now you can compute the total ionization loss
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ionloss -= delta + sh ;
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ionloss *= Factor*ElectronDensity/beta2 ;
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}
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if ( ionloss <= 0.)
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ionloss = 0. ;
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dEdx = ionloss ;
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return dEdx ;
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}
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G4VParticleChange* G4ionIonisation::PostStepDoIt(
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const G4Track& trackData,
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const G4Step& stepData)
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{
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const G4DynamicParticle* aParticle ;
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G4Material* aMaterial;
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G4double KineticEnergy,TotalEnergy,TotalMomentum,
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betasquare,MaxKineticEnergyTransfer,
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DeltaKineticEnergy,DeltaTotalMomentum,costheta,sintheta,phi,
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dirx,diry,dirz,finalKineticEnergy,finalPx,finalPy,finalPz,
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x,xc,grej,Psquare,Esquare,summass,rate,grejc,finalMomentum ;
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aParticleChange.Initialize(trackData) ;
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aMaterial = trackData.GetMaterial() ;
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aParticle = trackData.GetDynamicParticle() ;
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KineticEnergy=aParticle->GetKineticEnergy();
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TotalEnergy=KineticEnergy + ParticleMass ;
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Psquare=KineticEnergy*(TotalEnergy+ParticleMass) ;
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Esquare=TotalEnergy*TotalEnergy ;
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summass = ParticleMass + electron_mass_c2 ;
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G4ParticleMomentum ParticleDirection = aParticle->GetMomentumDirection() ;
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DeltaCutInKineticEnergyNow = DeltaCutInKineticEnergy[aMaterial->GetIndex()];
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// some kinematics......................
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betasquare=Psquare/Esquare ;
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MaxKineticEnergyTransfer = 2.*electron_mass_c2*Psquare
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/(summass*summass+2.*electron_mass_c2*KineticEnergy);
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// sampling kinetic energy of the delta ray
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if( MaxKineticEnergyTransfer <= DeltaCutInKineticEnergyNow )
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{
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// there is no change at all).....
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return G4VContinuousDiscreteProcess::PostStepDoIt(trackData,stepData);
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}
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else
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{
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// normal case ......................................
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xc=DeltaCutInKineticEnergyNow/MaxKineticEnergyTransfer ;
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rate=MaxKineticEnergyTransfer/TotalEnergy ;
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// sampling follows ...
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grejc=1.-betasquare*xc ;
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do {
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x=xc/(1.-(1.-xc)*G4UniformRand());
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grej=(1.-x*betasquare)/grejc ;
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} while( G4UniformRand()>grej );
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}
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DeltaKineticEnergy = x * MaxKineticEnergyTransfer ;
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if(DeltaKineticEnergy <= 0.)
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return G4VContinuousDiscreteProcess::PostStepDoIt(trackData,stepData);
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DeltaTotalMomentum = sqrt(DeltaKineticEnergy * (DeltaKineticEnergy +
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2. * electron_mass_c2 )) ;
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TotalMomentum = sqrt(Psquare) ;
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costheta = DeltaKineticEnergy * (TotalEnergy + electron_mass_c2)
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/(DeltaTotalMomentum * TotalMomentum) ;
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// protection against costheta > 1 or < -1 ---------------
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if ( costheta < -1. )
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costheta = -1. ;
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if ( costheta > +1. )
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costheta = +1. ;
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// direction of the delta electron ........
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phi = twopi * G4UniformRand() ;
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sintheta = sqrt((1.+costheta)*(1.-costheta));
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dirx = sintheta * cos(phi) ;
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diry = sintheta * sin(phi) ;
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dirz = costheta ;
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G4ThreeVector DeltaDirection(dirx,diry,dirz) ;
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DeltaDirection.rotateUz(ParticleDirection) ;
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// create G4DynamicParticle object for delta ray
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G4DynamicParticle *theDeltaRay = new G4DynamicParticle;
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theDeltaRay->SetKineticEnergy( DeltaKineticEnergy );
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theDeltaRay->SetMomentumDirection(
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DeltaDirection.x(),DeltaDirection.y(),DeltaDirection.z());
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theDeltaRay->SetDefinition(G4Electron::Electron());
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// fill aParticleChange
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finalKineticEnergy = KineticEnergy - DeltaKineticEnergy ;
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if (finalKineticEnergy > 0.)
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{
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// changed energy and momentum of the actual particle
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finalMomentum=sqrt(finalKineticEnergy*
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(finalKineticEnergy+2.*ParticleMass)) ;
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finalPx = (TotalMomentum*ParticleDirection.x()
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-DeltaTotalMomentum*DeltaDirection.x())/finalMomentum ;
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finalPy = (TotalMomentum*ParticleDirection.y()
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-DeltaTotalMomentum*DeltaDirection.y())/finalMomentum ;
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finalPz = (TotalMomentum*ParticleDirection.z()
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-DeltaTotalMomentum*DeltaDirection.z())/finalMomentum ;
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aParticleChange.SetMomentumChange( finalPx,finalPy,finalPz );
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}
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else
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{
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finalKineticEnergy = 0. ;
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aParticleChange.SetStatusChange(fStopAndKill);
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}
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aParticleChange.SetEnergyChange( finalKineticEnergy );
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aParticleChange.SetNumberOfSecondaries(1);
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aParticleChange.AddSecondary( theDeltaRay );
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return G4VContinuousDiscreteProcess::PostStepDoIt(trackData,stepData);
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}
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void G4ionIonisation::PrintInfoDefinition()
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{
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G4String comments = " Knock-on electron cross sections . ";
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comments += "\n MeanFreePath is computed at tracking time.\n";
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comments += " delta ray energy sampled from differential Xsection.";
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G4cout << G4endl << GetProcessName() << ": " << comments << G4endl;
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}
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