Import Geant4 0.0.0 source tree
This commit is contained in:
Gabriele Cosmo
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// This code implementation is the intellectual property of
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// the RD44 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: G4IMultipleScattering.icc,v 2.4 1998/11/13 08:00:07 urban Exp $
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// GEANT4 tag $Name: geant4-00 $
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//
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// $Id:
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// -------------------------------------------------------------
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// GEANT 4 class inlined methods 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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// ------- G4IMultipleScattering physics process ------
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// by Laszlo Urban, October 1997
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// **************************************************************
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// 25/11/97: mods for KinEnergy > HighestLimit
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//---------------------------------------------------------------
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// *****************************************************************
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// It is the first implementation of the multiple scattering process
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// using an INTEGRAL APPROACH instead of the differential
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// one used in the standard implementation .
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// *****************************************************************
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// by Laszlo Urban, 23 June 1998
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// -----------------------------------------------------------------
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// 27/10/98: cleanup , L.Urban
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inline G4double G4IMultipleScattering::TrueToGeomTransformation(
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const G4DynamicParticle *aParticle,
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G4Material *aMaterial,
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G4double truePathLength)
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// it sets the data member fTransportMeanFreePath and
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// performs the true path length -> geometrical path length
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// transformation
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{
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const G4double factt=1.-1.e-6,tausmall=5.e-5,taubig=50.,
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minim=1.e-6,smalldroverr=1.e-2,smalldToverT=2.e-2 ;
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G4double KineticEnergy,Tfinal,tau,etau,geomPathLength,range,w1,w2,ww1,ww2 ;
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G4int materialIndex ;
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G4bool isOut ;
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KineticEnergy = aParticle->GetKineticEnergy() ;
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if((lastMaterial == aMaterial) && (lastKineticEnergy == KineticEnergy))
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{ ; }
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else
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{
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lastMaterial=aMaterial;
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lastKineticEnergy=KineticEnergy;
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materialIndex = aMaterial->GetIndex() ;
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if(KineticEnergy<LowestKineticEnergy)
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{
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fTransportMeanFreePath =
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exp(plowlambda*log((KineticEnergy/LowestKineticEnergy)))*
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(*theTransportMeanFreePathTable)
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(materialIndex)->GetValue(LowestKineticEnergy,isOut);
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}
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else
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{
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if(KineticEnergy>HighestKineticEnergy)
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KineticEnergy=HighestKineticEnergy;
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fTransportMeanFreePath = (*theTransportMeanFreePathTable)
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(materialIndex)->GetValue(KineticEnergy,isOut);
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}
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}
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// do the true -> geom transformation
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if( fTransportMeanFreePath > biglambda )
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{
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geomPathLength = truePathLength ;
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CosTheta = 1. ;
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}
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else
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{
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const G4ParticleDefinition *theParticle = aParticle->GetDefinition() ;
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G4double range = G4EnergyLossTables::GetPreciseRangeFromEnergy(
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theParticle,KineticEnergy,aMaterial) ;
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if(truePathLength > factt*range)
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{
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geomPathLength = GetIntegralJ(theParticle,
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KineticEnergy,aMaterial) ;
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CosTheta = 0. ;
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}
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else
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{
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if(truePathLength/range < smalldroverr)
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{
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Tfinal = KineticEnergy - truePathLength*
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G4EnergyLossTables::GetPreciseDEDX(
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theParticle,KineticEnergy,aMaterial) ;
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}
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else
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{
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Tfinal = G4EnergyLossTables::GetPreciseEnergyFromRange(
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theParticle,range-truePathLength,
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aMaterial) ;
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}
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if((KineticEnergy-Tfinal)> smalldToverT)
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{
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w1 = GetIntegralI(theParticle,KineticEnergy,aMaterial) ;
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w2 = GetIntegralI(theParticle,Tfinal ,aMaterial) ;
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CosTheta = exp(w2-w1) ;
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if( CosTheta < minim)
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CosTheta = 0. ;
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ww1 = GetIntegralJ(theParticle,KineticEnergy,aMaterial) ;
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ww2 = GetIntegralJ(theParticle,Tfinal ,aMaterial) ;
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geomPathLength = ww1 - ww2*CosTheta ;
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}
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else
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{
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tau = truePathLength/fTransportMeanFreePath ;
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if(tau<tausmall)
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etau = tau ;
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else
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{
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if(tau>taubig)
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etau = 1. ;
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else
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etau = 1.-exp(-tau) ;
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}
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geomPathLength = fTransportMeanFreePath*etau ;
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CosTheta = exp(-truePathLength/fTransportMeanFreePath) ;
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}
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}
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}
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if(geomPathLength>truePathLength)
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geomPathLength = truePathLength ;
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tLast = truePathLength ;
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zLast = geomPathLength ;
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return geomPathLength ;
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}
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inline G4double G4IMultipleScattering::GetContinuousStepLimit(
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const G4Track& track,
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G4double,
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G4double currentMinimumStep,
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G4double&)
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{
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G4double zPathLength,tPathLength ;
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const G4DynamicParticle* aParticle ;
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// this process is not a candidate for selection!!!!!!!!!
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SetGPILSelection(NotCandidateForSelection) ;
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tPathLength = currentMinimumStep ;
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aParticle = track.GetDynamicParticle() ;
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zPathLength = TrueToGeomTransformation(aParticle,
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track.GetMaterial(),tPathLength);
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return zPathLength ;
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}
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inline G4double G4IMultipleScattering::GetMeanFreePath(const G4Track&,
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G4double,
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G4ForceCondition* condition)
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// it does not limit the Step size , but it sets condition to
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// Forced , because the PostStepDoIt always has to be called
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{
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*condition = Forced ;
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return DBL_MAX ;
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}
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inline G4VParticleChange* G4IMultipleScattering::AlongStepDoIt(
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const G4Track& track,const G4Step& Step)
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// only a geom path->true path transformation is performed
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{
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const G4double Tlowlimit=100.*keV ;
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const G4double fact = 1.-1.e-10 ;
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//!! const G4double tausmall=5.e-5,taubig=0.9999,trueBig=5. ;
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const G4double tausmall=5.e-5,taubig=0.9999,trueBig=9.21034 ;
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G4double tau ,geomPathLength, truePathLength ;
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aParticleChange.Initialize(track);
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geomPathLength = track.GetStepLength() ;
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//Store this value for later use in PostStepDoIt
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GeomStepFinal = geomPathLength ;
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if(geomPathLength == zLast)
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{
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truePathLength = tLast ;
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}
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else
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{
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if( fTransportMeanFreePath > biglambda )
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{
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truePathLength = track.GetStepLength() ;
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CosTheta = 1. ;
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}
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else
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{
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G4double T = track.GetDynamicParticle()->GetKineticEnergy() ;
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if(T < Tlowlimit)
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{ // spec. low energy msc code
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G4double range = G4EnergyLossTables::GetPreciseRangeFromEnergy(
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track.GetDynamicParticle()->GetDefinition(),
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T,track.GetMaterial()) ;
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G4double alfa = 1.+range/fTransportMeanFreePath ;
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G4double z = geomPathLength ;
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//protection: z can not be greater than zmax !!!!!!!
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G4double zmax = fact*range/alfa ;
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if(z > zmax)
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z = zmax ;
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if(z == zmax)
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{
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truePathLength = range ;
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CosTheta = 0. ;
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}
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else
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{
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truePathLength = range*
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(1.-exp(log(1.-alfa*z/range)/alfa)) ;
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CosTheta = (1.-alfa*z/range)/(1.-truePathLength/range) ;
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}
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}
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else
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{
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tau = geomPathLength/fTransportMeanFreePath ;
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if(tau<tausmall)
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truePathLength = fTransportMeanFreePath*tau*(1.+0.5*tau) ;
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else
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{
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if(tau<taubig)
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truePathLength = -fTransportMeanFreePath*log(1.-tau) ;
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else
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truePathLength = fTransportMeanFreePath*trueBig ;
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}
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CosTheta = exp(-truePathLength/fTransportMeanFreePath) ;
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}
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}
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}
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if(truePathLength<geomPathLength)
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truePathLength = geomPathLength ;
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aParticleChange.SetTrueStepLength(truePathLength) ;
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return &aParticleChange ;
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}
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inline G4bool G4IMultipleScattering::IsApplicable(
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const G4ParticleDefinition& particle)
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{
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return(particle.GetPDGCharge() != 0.);
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}
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