Gabriele Cosmo
835 lines
29 KiB
C++
835 lines
29 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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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 *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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//
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// $Id: G4IMultipleScattering.cc,v 1.1.2.2 2001/06/28 20:19:20 gunter Exp $
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// GEANT4 tag $Name: $
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//
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// $Id:
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// --------------------------------------------------------------
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// GEANT 4 class implementation file
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//
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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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// 09/12/98: charge can be != +- 1 !!!! L.Urban
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// ************************************************************
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// It is the first implementation of the
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// MULTIPLESCATTERING 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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#include "G4IMultipleScattering.hh"
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#include "G4UnitsTable.hh"
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G4IMultipleScattering::G4IMultipleScattering(const G4String& processName)
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: G4VContinuousDiscreteProcess(processName),
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theTransportMeanFreePathTable(NULL),
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theIntegralITable(NULL),
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theIntegralJTable(NULL),
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lastMaterial(NULL),
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lastKineticEnergy(-1.*MeV),
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fTransportMeanFreePath(1.e12),
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LowestKineticEnergy(0.1*keV),
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HighestKineticEnergy(100.*TeV),
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TotBin(100),
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NumberOfBuildPhysicsTableCalls(0),
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theElectron(G4Electron::Electron()),
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thePositron(G4Positron::Positron()),
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plowloss ( 0.5 ),
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plowlambda ( 0.4 ),
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tLast (0.0),
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zLast (0.0),
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CosTheta (1.0),
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biglambda ( 1.e10*mm),
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tuning(1.0)
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{ }
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G4IMultipleScattering::~G4IMultipleScattering()
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{
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if(theTransportMeanFreePathTable)
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{
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theTransportMeanFreePathTable->clearAndDestroy() ;
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delete theTransportMeanFreePathTable ;
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}
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if(theIntegralITable)
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{
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theIntegralITable->clearAndDestroy() ;
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delete theIntegralITable ;
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}
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if(theIntegralJTable)
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{
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theIntegralJTable->clearAndDestroy() ;
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delete theIntegralJTable ;
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}
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}
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void G4IMultipleScattering::BuildPhysicsTable(
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const G4ParticleDefinition& aParticleType)
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{
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NumberOfBuildPhysicsTableCalls += 1 ;
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if(NumberOfBuildPhysicsTableCalls == 1)
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{ ; }
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else
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{
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const G4MaterialTable* theMaterialTable =
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G4Material::GetMaterialTable() ;
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const G4double sigmafactor = twopi*classic_electr_radius*
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classic_electr_radius ;
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G4double KineticEnergy,AtomicNumber,sigma,lambda ;
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G4double density ;
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if(theTransportMeanFreePathTable)
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{
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theTransportMeanFreePathTable->clearAndDestroy() ;
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delete theTransportMeanFreePathTable ;
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}
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G4int numOfMaterials = theMaterialTable->length() ;
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theTransportMeanFreePathTable = new G4PhysicsTable(numOfMaterials) ;
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for (G4int J=0; J<numOfMaterials; J++)
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{
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G4PhysicsLogVector* aVector = new G4PhysicsLogVector(
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LowestKineticEnergy,HighestKineticEnergy,TotBin) ;
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const G4Material* material = (*theMaterialTable)(J) ;
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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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density = material->GetDensity() ;
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for (G4int i=0; i<TotBin; i++)
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{
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KineticEnergy = aVector->GetLowEdgeEnergy(i) ;
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sigma = 0. ;
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for (G4int iel=0; iel<NumberOfElements; iel++)
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{
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AtomicNumber = (*theElementVector)(iel)->GetZ() ;
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sigma += theAtomicNumDensityVector[iel]*
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ComputeTransportCrossSection(aParticleType,
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KineticEnergy,AtomicNumber) ;
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}
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sigma *= sigmafactor ;
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lambda = 1./sigma ;
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aVector->PutValue(i,lambda) ;
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}
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theTransportMeanFreePathTable->insert(aVector) ;
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}
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BuildIntegralITable(aParticleType) ;
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BuildIntegralJTable(aParticleType) ;
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NumberOfBuildPhysicsTableCalls = 0 ;
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if( (&aParticleType == G4Electron::Electron()) ||
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(&aParticleType == G4MuonPlus::MuonPlus()) ||
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(&aParticleType == G4Proton::Proton()) )
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{
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PrintInfoDefinition() ;
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}
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}
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}
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void G4IMultipleScattering::BuildIntegralITable(
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const G4ParticleDefinition& aParticleType)
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{
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const G4MaterialTable* theMaterialTable =
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G4Material::GetMaterialTable() ;
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G4Material* aMaterial ;
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G4double fmin,lmin,Value,KineticEnergy,lambda,Tlast,Vlast ;
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G4double u,umax,du,t,coeff,dEdx ;
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G4int n,nmax ;
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G4bool isOut ;
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const G4int nb = 100 ;
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G4double rmin ;
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if(theIntegralITable)
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{
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theIntegralITable->clearAndDestroy() ;
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delete theIntegralITable ;
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}
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G4int numOfMaterials = theMaterialTable->length() ;
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theIntegralITable = new G4PhysicsTable(numOfMaterials) ;
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for (G4int J=0; J<numOfMaterials; J++)
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{
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G4PhysicsLogVector* aVector = new G4PhysicsLogVector(
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LowestKineticEnergy,HighestKineticEnergy,TotBin) ;
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aMaterial = (*theMaterialTable)(J) ;
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rmin = G4EnergyLossTables::GetPreciseRangeFromEnergy(
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&aParticleType,
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LowestKineticEnergy,
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aMaterial) ;
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lmin = (*theTransportMeanFreePathTable)(J)->
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GetValue(LowestKineticEnergy,isOut) ;
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// this value comes from z=r*l/(r+l) = exp(-I) !!!
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Value = -log(rmin*lmin/(rmin+lmin)) ;
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aVector->PutValue(0,Value) ;
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Tlast = LowestKineticEnergy ;
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Vlast = Value ;
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for (G4int i=1; i<TotBin; i++)
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{
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KineticEnergy = aVector->GetLowEdgeEnergy(i) ;
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umax = log(KineticEnergy/Tlast) ;
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nmax = int(nb*umax + 0.5) ;
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if(nmax<1)
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nmax = 1 ;
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du = umax/nmax ;
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Value = 0. ;
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u = -du ;
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for(n=0; n<=nmax; n++)
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{
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u += du ;
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t = Tlast*exp(u) ;
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lambda = (*theTransportMeanFreePathTable)(J)->
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GetValue(t,isOut) ;
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dEdx = G4EnergyLossTables::GetPreciseDEDX(&aParticleType,
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t,aMaterial) ;
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if((n == 0) || (n == nmax))
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coeff = 0.5 ;
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else
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coeff = 1. ;
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Value += coeff*t/(dEdx*lambda) ;
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}
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Value *= du ;
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Value += Vlast ;
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aVector->PutValue(i,Value) ;
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Tlast = KineticEnergy ;
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Vlast = Value ;
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}
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theIntegralITable->insert(aVector) ;
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}
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}
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void G4IMultipleScattering::BuildIntegralJTable(
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const G4ParticleDefinition& aParticleType)
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{
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const G4MaterialTable* theMaterialTable =
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G4Material::GetMaterialTable() ;
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G4Material* aMaterial ;
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G4double rmin,lmin,Value,KineticEnergy,lambda,Tlast,Vlast ;
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G4double u,umax,du,t,coeff,dEdx,w,ww ;
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G4double cmin,lndu ;
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G4int n,nmax ;
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G4bool isOut ;
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const G4int nb = 100 ;
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if(theIntegralJTable)
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{
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theIntegralJTable->clearAndDestroy() ;
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delete theIntegralJTable ;
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}
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G4int numOfMaterials = theMaterialTable->length() ;
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theIntegralJTable = new G4PhysicsTable(numOfMaterials) ;
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for (G4int J=0; J<numOfMaterials; J++)
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{
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G4PhysicsLogVector* aVector = new G4PhysicsLogVector(
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LowestKineticEnergy,HighestKineticEnergy,TotBin) ;
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aMaterial = (*theMaterialTable)(J) ;
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rmin = G4EnergyLossTables::GetPreciseRangeFromEnergy(
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&aParticleType,
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LowestKineticEnergy,
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aMaterial) ;
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lmin = (*theTransportMeanFreePathTable)(J)->
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GetValue(LowestKineticEnergy,isOut) ;
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Value = rmin*lmin/(rmin+lmin) ;
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aVector->PutValue(0,Value) ;
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Tlast = LowestKineticEnergy ;
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Vlast = Value ;
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for (G4int i=1; i<TotBin; i++)
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{
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KineticEnergy = aVector->GetLowEdgeEnergy(i) ;
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umax = log(KineticEnergy/Tlast) ;
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nmax =int(nb*umax + 0.5) ;
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if(nmax<1)
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nmax = 1 ;
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du = umax/nmax ;
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Value = 0. ;
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u = -du ;
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for(n=0; n<=nmax; n++)
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{
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u += du ;
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t = Tlast*exp(u) ;
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w = (*theIntegralITable)(J)->
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GetValue(t,isOut) ;
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dEdx = G4EnergyLossTables::GetPreciseDEDX(&aParticleType,
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t,aMaterial) ;
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if((n == 0) || (n == nmax))
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coeff = 0.5 ;
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else
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coeff = 1. ;
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Value += coeff*t*exp(w)/dEdx ;
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}
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Value *= du ;
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w = (*theIntegralITable)(J)->
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GetValue(Tlast,isOut) ;
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ww = (*theIntegralITable)(J)->
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GetValue(KineticEnergy,isOut) ;
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Value *= exp(-ww) ;
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Value += exp(w-ww)*Vlast ;
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aVector->PutValue(i,Value) ;
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Tlast = KineticEnergy ;
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Vlast = Value ;
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}
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theIntegralJTable->insert(aVector) ;
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}
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}
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G4double G4IMultipleScattering::GetIntegralI(
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const G4ParticleDefinition *aParticle,
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G4double KineticEnergy,
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G4Material* aMaterial)
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{
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G4double intI ;
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G4bool isOut ;
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if(KineticEnergy < LowestKineticEnergy)
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{
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intI = (*theIntegralITable)(aMaterial->GetIndex())->
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GetValue(LowestKineticEnergy,isOut) ;
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intI *= exp((1.-plowloss-plowlambda)*
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log(KineticEnergy/LowestKineticEnergy)) ;
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}
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else if(KineticEnergy <= HighestKineticEnergy)
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{
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intI = (*theIntegralITable)(aMaterial->GetIndex())->
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GetValue(KineticEnergy,isOut) ;
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}
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else
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{
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intI = (*theIntegralITable)(aMaterial->GetIndex())->
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GetValue(HighestKineticEnergy,isOut) ;
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intI += (KineticEnergy-HighestKineticEnergy)/
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((*theTransportMeanFreePathTable)(aMaterial->GetIndex())->
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GetValue(HighestKineticEnergy,isOut)
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*
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G4EnergyLossTables::GetPreciseDEDX(aParticle,
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HighestKineticEnergy,aMaterial)) ;
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}
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return intI ;
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}
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G4double G4IMultipleScattering::GetIntegralJ(
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const G4ParticleDefinition *aParticle,
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G4double KineticEnergy,
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G4Material* aMaterial)
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{
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G4double intJ,lmin,lmax,fmax,Imin,Imin2,t ;
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G4bool isOut ;
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if(KineticEnergy < LowestKineticEnergy)
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{
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lmin = (*theTransportMeanFreePathTable)(aMaterial->GetIndex())->
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GetValue(KineticEnergy,isOut) ;
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Imin = (*theIntegralITable)(aMaterial->GetIndex())->
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GetValue(LowestKineticEnergy,isOut) ;
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Imin2= Imin*Imin ;
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t = exp(0.1*log(KineticEnergy/LowestKineticEnergy)) ;
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intJ = (((t-4./Imin)*t+12./Imin2)*t-24./(Imin*Imin2))*t+24./(Imin2*Imin2);
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intJ -= 24.*exp(-Imin*t)/(Imin2*Imin2) ;
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intJ *= lmin ;
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}
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else if(KineticEnergy <= HighestKineticEnergy)
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{
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intJ = (*theIntegralJTable)(aMaterial->GetIndex())->
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GetValue(KineticEnergy,isOut) ;
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}
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else
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{
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lmax = (*theTransportMeanFreePathTable)(aMaterial->GetIndex())->
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GetValue(HighestKineticEnergy,isOut) ;
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fmax = G4EnergyLossTables::GetPreciseDEDX(aParticle,
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HighestKineticEnergy,aMaterial) ;
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intJ = lmax - (lmax-(*theIntegralJTable)(aMaterial->GetIndex())->
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GetValue(HighestKineticEnergy,isOut))*
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exp((HighestKineticEnergy-KineticEnergy)/(fmax*lmax)) ;
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}
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return intJ ;
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}
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G4double G4IMultipleScattering::ComputeTransportCrossSection(
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const G4ParticleDefinition& aParticleType,
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G4double KineticEnergy,
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G4double AtomicNumber)
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{
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const G4double epsfactor = 2.*electron_mass_c2*electron_mass_c2*
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Bohr_radius*Bohr_radius/(hbarc*hbarc) ;
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const G4double epsmin = 1.e-4 , epsmax = 1.e10 ;
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const G4double cpar=1.50 ;
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const G4double Zdat[15] = {4.,6.,13.,20.,26.,29.,32.,38.,47.,
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50.,56.,64.,74.,79.,82. } ;
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const G4double Tdat[22] =
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{ 0.0001*MeV,0.0002*MeV,0.0004*MeV,0.0007*MeV,
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0.001*MeV,0.002*MeV,0.004*MeV,0.007*MeV,0.01*MeV,
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0.02*MeV,0.04*MeV,0.07*MeV,0.1*MeV,0.2*MeV,
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0.4*MeV,0.7*MeV,1.*MeV,2.*MeV,4.*MeV,
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7.*MeV,10.*MeV,20.*MeV} ;
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// corr. factors for e-/e+ lambda
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const G4double celectron[15][22] =
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{{1.125,1.072,1.051,1.047,1.047,1.050,1.052,1.054,
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1.054,1.057,1.062,1.069,1.075,1.090,1.105,1.111,
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1.112,1.108,1.100,1.093,1.089,1.087 },
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{1.408,1.246,1.143,1.096,1.077,1.059,1.053,1.051,
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1.052,1.053,1.058,1.065,1.072,1.087,1.101,1.108,
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1.109,1.105,1.097,1.090,1.086,1.082 },
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{2.833,2.268,1.861,1.612,1.486,1.309,1.204,1.156,
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1.136,1.114,1.106,1.106,1.109,1.119,1.129,1.132,
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1.131,1.124,1.113,1.104,1.099,1.098 },
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{3.879,3.016,2.380,2.007,1.818,1.535,1.340,1.236,
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1.190,1.133,1.107,1.099,1.098,1.103,1.110,1.113,
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1.112,1.105,1.096,1.089,1.085,1.098 },
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{6.937,4.330,2.886,2.256,1.987,1.628,1.395,1.265,
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1.203,1.122,1.080,1.065,1.061,1.063,1.070,1.073,
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1.073,1.070,1.064,1.059,1.056,1.056 },
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{9.616,5.708,3.424,2.551,2.204,1.762,1.485,1.330,
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1.256,1.155,1.099,1.077,1.070,1.068,1.072,1.074,
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1.074,1.070,1.063,1.059,1.056,1.052 },
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{11.72,6.364,3.811,2.806,2.401,1.884,1.564,1.386,
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1.300,1.180,1.112,1.082,1.073,1.066,1.068,1.069,
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1.068,1.064,1.059,1.054,1.051,1.050 },
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{18.08,8.601,4.569,3.183,2.662,2.025,1.646,1.439,
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1.339,1.195,1.108,1.068,1.053,1.040,1.039,1.039,
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1.039,1.037,1.034,1.031,1.030,1.036 },
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{18.22,10.48,5.333,3.713,3.115,2.367,1.898,1.631,
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1.498,1.301,1.171,1.105,1.077,1.048,1.036,1.033,
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1.031,1.028,1.024,1.022,1.021,1.024 },
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{14.14,10.65,5.710,3.929,3.266,2.453,1.951,1.669,
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1.528,1.319,1.178,1.106,1.075,1.040,1.027,1.022,
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1.020,1.017,1.015,1.013,1.013,1.020 },
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{14.11,11.73,6.312,4.240,3.478,2.566,2.022,1.720,
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1.569,1.342,1.186,1.102,1.065,1.022,1.003,0.997,
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0.995,0.993,0.993,0.993,0.993,1.011 },
|
|
{22.76,20.01,8.835,5.287,4.144,2.901,2.219,1.855,
|
|
1.677,1.410,1.224,1.121,1.073,1.014,0.986,0.976,
|
|
0.974,0.972,0.973,0.974,0.975,0.987 },
|
|
{50.77,40.85,14.13,7.184,5.284,3.435,2.520,2.059,
|
|
1.837,1.512,1.283,1.153,1.091,1.010,0.969,0.954,
|
|
0.950,0.947,0.949,0.952,0.954,0.963 },
|
|
{65.87,59.06,15.87,7.570,5.567,3.650,2.682,2.182,
|
|
1.939,1.579,1.325,1.178,1.108,1.014,0.965,0.947,
|
|
0.941,0.938,0.940,0.944,0.946,0.954 },
|
|
// {45.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239, misprint?
|
|
{55.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239,
|
|
1.985,1.609,1.343,1.188,1.113,1.013,0.960,0.939,
|
|
0.933,0.930,0.933,0.936,0.939,0.949 }};
|
|
|
|
const G4double cpositron[15][22] = {
|
|
{2.589,2.044,1.658,1.446,1.347,1.217,1.144,1.110,
|
|
1.097,1.083,1.080,1.086,1.092,1.108,1.123,1.131,
|
|
1.131,1.126,1.117,1.108,1.103,1.100 },
|
|
{3.904,2.794,2.079,1.710,1.543,1.325,1.202,1.145,
|
|
1.122,1.096,1.089,1.092,1.098,1.114,1.130,1.137,
|
|
1.138,1.132,1.122,1.113,1.108,1.102 },
|
|
{7.970,6.080,4.442,3.398,2.872,2.127,1.672,1.451,
|
|
1.357,1.246,1.194,1.179,1.178,1.188,1.201,1.205,
|
|
1.203,1.190,1.173,1.159,1.151,1.145 },
|
|
{9.714,7.607,5.747,4.493,3.815,2.777,2.079,1.715,
|
|
1.553,1.353,1.253,1.219,1.211,1.214,1.225,1.228,
|
|
1.225,1.210,1.191,1.175,1.166,1.174 },
|
|
{17.97,12.95,8.628,6.065,4.849,3.222,2.275,1.820,
|
|
1.624,1.382,1.259,1.214,1.202,1.202,1.214,1.219,
|
|
1.217,1.203,1.184,1.169,1.160,1.151 },
|
|
{24.83,17.06,10.84,7.355,5.767,3.707,2.546,1.996,
|
|
1.759,1.465,1.311,1.252,1.234,1.228,1.238,1.241,
|
|
1.237,1.222,1.201,1.184,1.174,1.159 },
|
|
{23.26,17.15,11.52,8.049,6.375,4.114,2.792,2.155,
|
|
1.880,1.535,1.353,1.281,1.258,1.247,1.254,1.256,
|
|
1.252,1.234,1.212,1.194,1.183,1.170 },
|
|
{22.33,18.01,12.86,9.212,7.336,4.702,3.117,2.348,
|
|
2.015,1.602,1.385,1.297,1.268,1.251,1.256,1.258,
|
|
1.254,1.237,1.214,1.195,1.185,1.179 },
|
|
{33.91,24.13,15.71,10.80,8.507,5.467,3.692,2.808,
|
|
2.407,1.873,1.564,1.425,1.374,1.330,1.324,1.320,
|
|
1.312,1.288,1.258,1.235,1.221,1.205 },
|
|
{32.14,24.11,16.30,11.40,9.015,5.782,3.868,2.917,
|
|
2.490,1.925,1.596,1.447,1.391,1.342,1.332,1.327,
|
|
1.320,1.294,1.264,1.240,1.226,1.214 },
|
|
{29.51,24.07,17.19,12.28,9.766,6.238,4.112,3.066,
|
|
2.602,1.995,1.641,1.477,1.414,1.356,1.342,1.336,
|
|
1.328,1.302,1.270,1.245,1.231,1.233 },
|
|
{38.19,30.85,21.76,15.35,12.07,7.521,4.812,3.498,
|
|
2.926,2.188,1.763,1.563,1.484,1.405,1.382,1.371,
|
|
1.361,1.330,1.294,1.267,1.251,1.239 },
|
|
{49.71,39.80,27.96,19.63,15.36,9.407,5.863,4.155,
|
|
3.417,2.478,1.944,1.692,1.589,1.480,1.441,1.423,
|
|
1.409,1.372,1.330,1.298,1.280,1.258 },
|
|
{59.25,45.08,30.36,20.83,16.15,9.834,6.166,4.407,
|
|
3.641,2.648,2.064,1.779,1.661,1.531,1.482,1.459,
|
|
1.442,1.400,1.354,1.319,1.299,1.272 },
|
|
{56.38,44.29,30.50,21.18,16.51,10.11,6.354,4.542,
|
|
3.752,2.724,2.116,1.817,1.692,1.554,1.499,1.474,
|
|
1.456,1.412,1.364,1.328,1.307,1.282 }};
|
|
G4double Z23,ParticleMass,rat2,Charge,TotalEnergy,beta2,bg2,
|
|
eps,Z1,Z2,ratZ,T,E,b2small,b2big,ratb2,c1,c2,cc1,cc2,
|
|
corr,sigma,corrfactor,ChargeSquare ;
|
|
G4int iZ,iT ;
|
|
|
|
Z23 = 2.*log(AtomicNumber)/3. ;
|
|
Z23 = exp(Z23) ;
|
|
|
|
ParticleMass = aParticleType.GetPDGMass() ;
|
|
|
|
rat2 = ParticleMass/electron_mass_c2 ;
|
|
rat2 = rat2*rat2 ;
|
|
|
|
Charge = aParticleType.GetPDGCharge() ;
|
|
ChargeSquare = Charge*Charge/(eplus*eplus) ;
|
|
|
|
TotalEnergy = KineticEnergy + ParticleMass ;
|
|
|
|
beta2 = KineticEnergy*(TotalEnergy+ParticleMass)/
|
|
(TotalEnergy*TotalEnergy) ;
|
|
bg2 = KineticEnergy*(TotalEnergy+ParticleMass)/
|
|
(ParticleMass*ParticleMass) ;
|
|
|
|
eps = rat2*epsfactor*bg2/Z23 ;
|
|
|
|
if(eps<epsmin)
|
|
sigma = 2.*eps*eps*eps/3. ;
|
|
else if(eps<epsmax)
|
|
sigma = log(1.+2.*eps)-2.*eps/(1.+eps) ;
|
|
else
|
|
sigma = log(2.*eps)-2.+2.5/eps ;
|
|
|
|
sigma *= ChargeSquare*AtomicNumber*AtomicNumber/rat2 ;
|
|
sigma /= beta2*bg2 ;
|
|
|
|
// correct this value using the corrections computed for e+/e-
|
|
KineticEnergy *= electron_mass_c2/ParticleMass ;
|
|
|
|
// interpolate in AtomicNumber and beta2
|
|
|
|
// get bin number in Z
|
|
iZ = 14 ;
|
|
|
|
while ((iZ>=0)&&(Zdat[iZ]>=AtomicNumber))
|
|
{
|
|
iZ -= 1 ;
|
|
}
|
|
if(iZ==14)
|
|
{
|
|
iZ = 13 ;
|
|
}
|
|
if(iZ==-1)
|
|
{
|
|
iZ = 0 ;
|
|
}
|
|
|
|
Z1 = Zdat[iZ] ;
|
|
Z2 = Zdat[iZ+1] ;
|
|
ratZ = (AtomicNumber-Z1)/(Z2-Z1) ;
|
|
|
|
// get bin number in T (beta2)
|
|
iT = 21 ;
|
|
while ((iT>=0)&&(Tdat[iT]>=KineticEnergy))
|
|
iT -= 1 ;
|
|
if(iT==21)
|
|
iT = 20 ;
|
|
if(iT==-1)
|
|
iT = 0 ;
|
|
|
|
// calculate betasquare values
|
|
T = Tdat[iT] ;
|
|
E = T + electron_mass_c2 ;
|
|
b2small = T*(E+electron_mass_c2)/(E*E) ;
|
|
T = Tdat[iT+1] ;
|
|
E = T + electron_mass_c2 ;
|
|
b2big = T*(E+electron_mass_c2)/(E*E) ;
|
|
ratb2 = (beta2-b2small)/(b2big-b2small) ;
|
|
|
|
corrfactor = tuning*(1.+cpar)/(1.+cpar*beta2) ;
|
|
|
|
if(Charge < 0.)
|
|
{
|
|
c1 = celectron[iZ][iT] ;
|
|
c2 = celectron[iZ+1][iT] ;
|
|
cc1 = c1+ratZ*(c2-c1) ;
|
|
|
|
c1 = celectron[iZ][iT+1] ;
|
|
c2 = celectron[iZ+1][iT+1] ;
|
|
cc2 = c1+ratZ*(c2-c1) ;
|
|
|
|
corr = cc1+ratb2*(cc2-cc1) ;
|
|
|
|
sigma /= corr ;
|
|
|
|
}
|
|
|
|
if(Charge > 0.)
|
|
{
|
|
c1 = cpositron[iZ][iT] ;
|
|
c2 = cpositron[iZ+1][iT] ;
|
|
cc1 = c1+ratZ*(c2-c1) ;
|
|
|
|
c1 = cpositron[iZ][iT+1] ;
|
|
c2 = cpositron[iZ+1][iT+1] ;
|
|
cc2 = c1+ratZ*(c2-c1) ;
|
|
|
|
corr = cc1+ratb2*(cc2-cc1) ;
|
|
|
|
sigma /= corr ;
|
|
}
|
|
|
|
sigma *= corrfactor ;
|
|
|
|
return sigma ;
|
|
}
|
|
|
|
|
|
|
|
G4VParticleChange* G4IMultipleScattering::PostStepDoIt(
|
|
const G4Track& trackData,
|
|
const G4Step& stepData)
|
|
{
|
|
G4double lambdasave ;
|
|
const G4double taulim = 1.e-10 , randlim = 0.25*taulim*taulim ;
|
|
const G4double tausmall = 5.e-5,taubig =50.;
|
|
|
|
const G4double scatteringparameter=1.00 ,
|
|
kappa = 2.5, kappapl1 = kappa+1., kappami1 = kappa-1. ;
|
|
|
|
const G4DynamicParticle* aParticle ;
|
|
G4Material* aMaterial ;
|
|
G4int materialIndex ;
|
|
G4double KineticEnergy,truestep,tau,prob,cth,sth,phi,
|
|
dirx,diry,dirz,w,w1,etau,rmean,safetyminustolerance,
|
|
xnew,ynew,znew ;
|
|
G4double rand,rmax2 ;
|
|
G4bool isOut;
|
|
|
|
aParticleChange.Initialize(trackData) ;
|
|
|
|
aMaterial = stepData.GetPreStepPoint()->GetMaterial() ;
|
|
|
|
|
|
truestep = stepData.GetStepLength() ;
|
|
|
|
// there is no scattering for truestep=0. !
|
|
if(truestep == 0.)
|
|
return &aParticleChange ;
|
|
|
|
aParticle = trackData.GetDynamicParticle() ;
|
|
|
|
materialIndex = aMaterial->GetIndex() ;
|
|
KineticEnergy = aParticle->GetKineticEnergy() ;
|
|
|
|
// shortcut if the particle is not Alive (e.g. stopped in energy loss)
|
|
if(trackData.GetTrackStatus() != fAlive)
|
|
return &aParticleChange ;
|
|
|
|
if ((lastMaterial == aMaterial) && (lastKineticEnergy == KineticEnergy))
|
|
{
|
|
;
|
|
}
|
|
else
|
|
{
|
|
lastMaterial=aMaterial;
|
|
lastKineticEnergy=KineticEnergy;
|
|
if(KineticEnergy<LowestKineticEnergy)
|
|
{
|
|
fTransportMeanFreePath =
|
|
exp(plowlambda*log(KineticEnergy/LowestKineticEnergy))*
|
|
(*theTransportMeanFreePathTable)
|
|
(materialIndex)->GetValue(LowestKineticEnergy,isOut);
|
|
}
|
|
else
|
|
{
|
|
// TransportMeanFreePath taken at kin.energy after the energy loss!
|
|
if(KineticEnergy>HighestKineticEnergy)
|
|
KineticEnergy = HighestKineticEnergy ;
|
|
fTransportMeanFreePath = (*theTransportMeanFreePathTable)
|
|
(materialIndex)->GetValue(KineticEnergy,isOut);
|
|
}
|
|
}
|
|
|
|
// effective lambda used in scattering .....................
|
|
lambdasave = fTransportMeanFreePath ;
|
|
|
|
if(CosTheta == 1.)
|
|
{
|
|
fTransportMeanFreePath = biglambda ;
|
|
tau = 0.;
|
|
cth = 1. ;
|
|
}
|
|
else if(CosTheta == 0.)
|
|
{
|
|
fTransportMeanFreePath = 0. ;
|
|
tau = biglambda ;
|
|
cth = -1.+2.*G4UniformRand() ;
|
|
}
|
|
else
|
|
{
|
|
fTransportMeanFreePath = -truestep/log(CosTheta) ;
|
|
tau = truestep/fTransportMeanFreePath ;
|
|
prob = exp(-tau)*(1.+scatteringparameter*tau) ;
|
|
|
|
if(G4UniformRand()<prob)
|
|
{
|
|
if(tau<taulim)
|
|
{
|
|
rand = G4UniformRand() ;
|
|
if(rand > randlim)
|
|
cth = 1.-tau*(1./sqrt(rand)-1.) ;
|
|
else
|
|
cth = -1. ;
|
|
}
|
|
else
|
|
{
|
|
w = 1.+scatteringparameter*tau ;
|
|
w1 = w-1. ;
|
|
cth = w-w1*(w+1.)/sqrt(w1*w1+4.*w*G4UniformRand()) ;
|
|
}
|
|
}
|
|
else
|
|
cth = -1.+2.*G4UniformRand() ;
|
|
}
|
|
|
|
sth = sqrt(1.-cth*cth) ;
|
|
phi = twopi*G4UniformRand() ;
|
|
|
|
dirx = sth*cos(phi) ;
|
|
diry = sth*sin(phi) ;
|
|
dirz = cth ;
|
|
|
|
G4ParticleMomentum ParticleDirection = aParticle->GetMomentumDirection();
|
|
G4ThreeVector newDirection(dirx,diry,dirz) ;
|
|
newDirection.rotateUz(ParticleDirection) ;
|
|
aParticleChange.SetNumberOfSecondaries(0) ;
|
|
aParticleChange.SetEnergyChange( KineticEnergy ) ;
|
|
aParticleChange.SetMomentumChange(newDirection.x(),
|
|
newDirection.y(),
|
|
newDirection.z()) ;
|
|
|
|
// compute lateral displacement
|
|
// only for safety > tolerance !!!!!
|
|
safetyminustolerance = stepData.GetPostStepPoint()->GetSafety()
|
|
-kCarTolerance ;
|
|
if(safetyminustolerance > 0.)
|
|
{
|
|
if(truestep == GeomStepFinal)
|
|
{ ; }
|
|
else
|
|
{
|
|
rmax2 = (truestep+GeomStepFinal)*(truestep-GeomStepFinal) ;
|
|
if(tau<tausmall)
|
|
rmean = 5.*tau*tau*tau/12. ;
|
|
else
|
|
{
|
|
if(tau<taubig)
|
|
etau = exp(-tau) ;
|
|
else
|
|
etau = 0. ;
|
|
rmean = -kappa*tau ;
|
|
rmean = -exp(rmean)/(kappa*kappami1) ;
|
|
rmean += tau-kappapl1/kappa+kappa*etau/kappami1 ;
|
|
}
|
|
rmean *= 4.*fTransportMeanFreePath*fTransportMeanFreePath/3.;
|
|
if(rmean>rmax2)
|
|
rmean = rmax2 ;
|
|
|
|
if(rmean>0.)
|
|
{
|
|
rmean = sqrt(rmean) ;
|
|
|
|
if(rmean>safetyminustolerance)
|
|
rmean = safetyminustolerance ;
|
|
|
|
fMeanLateralDisplacement = rmean ;
|
|
|
|
// sample direction of lateral displacement
|
|
phi = twopi*G4UniformRand() ;
|
|
dirx = cos(phi) ;
|
|
diry = sin(phi) ;
|
|
dirz = 0. ;
|
|
G4ThreeVector latDirection(dirx,diry,dirz);
|
|
latDirection.rotateUz(ParticleDirection) ;
|
|
|
|
// compute new endpoint of the Step
|
|
xnew = stepData.GetPostStepPoint()->GetPosition().x()+
|
|
rmean*latDirection.x() ;
|
|
ynew = stepData.GetPostStepPoint()->GetPosition().y()+
|
|
rmean*latDirection.y() ;
|
|
znew = stepData.GetPostStepPoint()->GetPosition().z()+
|
|
rmean*latDirection.z() ;
|
|
|
|
aParticleChange.SetPositionChange(xnew,ynew,znew) ;
|
|
}
|
|
}
|
|
}
|
|
|
|
fTransportMeanFreePath = lambdasave ;
|
|
|
|
return &aParticleChange ;
|
|
|
|
}
|
|
|
|
void G4IMultipleScattering::PrintInfoDefinition()
|
|
{
|
|
G4String comments = " Tables of transport mean free paths.";
|
|
comments += "\n New model of MSC , computes the lateral \n";
|
|
comments += " displacement of the particle , too.";
|
|
|
|
G4cout << G4endl << GetProcessName() << ": " << comments
|
|
<< "\n PhysicsTables from " << G4BestUnit(LowestKineticEnergy,
|
|
"Energy")
|
|
<< " to " << G4BestUnit(HighestKineticEnergy,"Energy")
|
|
<< " in " << TotBin << " bins. \n";
|
|
}
|
|
|