Import Geant4 5.0.0 source tree
This commit is contained in:
Gabriele Cosmo
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//
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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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// -------------------------------------------------------------------
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//
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// GEANT4 Class file
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//
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//
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// File name: G4MuPairProductionModel
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//
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// Author: Vladimir Ivanchenko on base of Laszlo Urban code
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//
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// Creation date: 24.06.2002
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//
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// Modifications: 04.12.2002 Change G4DynamicParticle constructor in PostStep (VI)
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//
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// Class Description:
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//
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//
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// -------------------------------------------------------------------
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//
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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#include "G4MuPairProductionModel.hh"
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#include "G4Electron.hh"
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#include "G4Positron.hh"
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#include "G4MuonMinus.hh"
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#include "G4MuonPlus.hh"
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#include "Randomize.hh"
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#include "G4Material.hh"
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#include "G4Element.hh"
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#include "G4ElementVector.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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// static members
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//
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G4double G4MuPairProductionModel::zdat[]={1.,4.,13.,29.,92.};
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G4double G4MuPairProductionModel::adat[]={1.01,9.01,26.98,63.55,238.03};
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G4double G4MuPairProductionModel::tdat[]={1.e3,1.e4,1.e5,1.e6,1.e7,1.e8,1.e9,1.e10};
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4MuPairProductionModel::G4MuPairProductionModel(const G4ParticleDefinition* p)
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: G4VEmModel(),
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minPairEnergy(4.*electron_mass_c2),
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highKinEnergy(1000000.*TeV),
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lowKinEnergy(minPairEnergy),
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minThreshold(minPairEnergy),
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nzdat(5),
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ntdat(8),
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NBIN(1000),
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oldMaterial(0),
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samplingTablesAreFilled(false)
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{
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partialSumSigma.clear();
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4MuPairProductionModel::~G4MuPairProductionModel()
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{
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size_t n = partialSumSigma.size();
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if(n > 0) {
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for(size_t i=0; i<n; i++) {
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delete partialSumSigma[i];
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}
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4MuPairProductionModel::HighEnergyLimit(const G4ParticleDefinition* p,
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const G4Material*)
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{
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return highKinEnergy;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4MuPairProductionModel::LowEnergyLimit(const G4ParticleDefinition* p,
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const G4Material*)
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{
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return lowKinEnergy;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4MuPairProductionModel::MinEnergyCut(const G4ParticleDefinition* p,
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const G4Material* material)
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{
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G4double eCut = (G4Electron::Electron())->GetEnergyThreshold(material);
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G4double pCut = (G4Positron::Positron())->GetEnergyThreshold(material);
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G4double x = minPairEnergy;
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if(eCut < highKinEnergy && pCut < highKinEnergy) {
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x += eCut + pCut;
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} else {
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x = 0.5*highKinEnergy;
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}
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return x;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4bool G4MuPairProductionModel::IsInCharge(const G4ParticleDefinition* p,
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const G4Material*)
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{
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return (p == G4MuonMinus::MuonMinus() || p == G4MuonPlus::MuonPlus());
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4MuPairProductionModel::ComputeDEDX(const G4Material* material,
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const G4ParticleDefinition* p,
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G4double kineticEnergy,
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G4double cutEnergy)
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{
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G4double dedx = 0.0;
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if(!samplingTablesAreFilled) {
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minThreshold = MinEnergyCut(p, material);
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MakeSamplingTables();
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}
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if(kineticEnergy < minPairEnergy) return dedx;
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const G4ElementVector* theElementVector = material->GetElementVector();
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const G4double* theAtomicNumDensityVector = material->GetAtomicNumDensityVector();
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// loop for elements in the material
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for (size_t i=0; i<material->GetNumberOfElements(); i++) {
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G4double Z = (*theElementVector)[i]->GetZ();
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G4double loss = ComputMuPairLoss(Z, kineticEnergy, cutEnergy);
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dedx += loss*theAtomicNumDensityVector[i];
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}
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if(dedx < 0.) dedx = 0.;
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return dedx;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4MuPairProductionModel::ComputMuPairLoss(G4double Z,
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G4double tkin, G4double cutEnergy)
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{
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static const
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G4double xgi[] ={ 0.0199,0.1017,0.2372,0.4083,0.5917,0.7628,0.8983,0.9801};
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static const
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G4double wgi[] ={ 0.0506,0.1112,0.1569,0.1813,0.1813,0.1569,0.1112,0.0506};
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static const G4double ak1=6.9;
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static const G4double ak2=1.0;
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static const G4double sqrte = sqrt(exp(1.));
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static const G4double aaa = log(minPairEnergy);
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G4double z13 = pow(Z,0.333333333);
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G4double loss = 0.0 ;
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if (Z < 1. || cutEnergy < minPairEnergy) return loss;
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G4double particleMass = (G4MuonPlus::MuonPlus())->GetPDGMass();
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G4double tmax = tkin + particleMass*(1.-0.75*sqrte*z13);
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// G4cout << "###DEDX tkin= " << tkin << " tmax= " << tmax << " tmin= " << minPairEnergy << G4endl;
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if(tmax < minPairEnergy) tmax = minPairEnergy;
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G4double cut = cutEnergy;
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if(cut >= tmax) cut = tmax;
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if(cut <= minPairEnergy) return loss;
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// calculate the rectricted loss
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// numerical integration in log(PairEnergy)
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G4double bbb = log(cut) ;
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G4int kkk = (G4int)((bbb-aaa)/ak1+ak2);
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if(kkk > 8) kkk = 8;
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G4double hhh = (bbb-aaa)/(G4double)kkk ;
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G4double x = aaa;
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// G4cout << "###DEDX tkin= " << tkin << " cut= " << cut << " kkk= " << kkk << G4endl;
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for (G4int l=0 ; l<kkk; l++)
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{
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for (G4int ll=0; ll<8; ll++)
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{
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G4double ep = exp(x+xgi[ll]*hhh);
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// G4cout << "ep= " << ep << G4endl;
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loss += wgi[ll]*ep*ep*ComputeDMicroscopicCrossSection(tkin, Z, ep);
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}
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x += hhh;
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}
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loss *= hhh ;
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// cout << "### tmax= " << tmax << " hhh= " << hhh << " loss= " << loss << endl;
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if (loss < 0.) loss = 0.;
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return loss ;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4MuPairProductionModel::ComputeMicroscopicCrossSection(
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G4double tkin,
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G4double Z,
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G4double A,
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G4double cut)
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{
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static const G4double ak1=6.9 ;
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static const G4double ak2=1.0 ;
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static const G4double sqrte = sqrt(exp(1.)) ;
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static const G4double
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xgi[]={ 0.0199,0.1017,0.2372,0.4083,0.5917,0.7628,0.8983,0.9801 };
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static const G4double
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wgi[]={ 0.0506,0.1112,0.1569,0.1813,0.1813,0.1569,0.1112,0.0506 };
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G4double z13 = pow(Z,0.333333333);
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G4double cross = 0. ;
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if(Z < 1.) return cross;
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G4double particleMass = (G4MuonPlus::MuonPlus())->GetPDGMass();
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G4double tmax = tkin + particleMass*(1.-0.75*sqrte*z13);
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if(tmax < minPairEnergy) tmax = minPairEnergy;
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if(tmax <= cut) return cross;
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G4double aaa = log(cut);
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G4double bbb = log(tmax);
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G4int kkk = (G4int)((bbb-aaa)/ak1 + ak2);
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if(kkk > 8) kkk = 8;
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G4double hhh = (bbb-aaa)/float(kkk);
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G4double x = aaa;
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// G4cout << "###Cross tkin= " << tkin << " cut= " << cut << " kkk= " << kkk << G4endl;
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for(G4int l=0; l<kkk; l++)
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{
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for(G4int i=0; i<8; i++)
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{
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G4double ep = exp(x + xgi[i]*hhh);
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cross += ep*wgi[i]*ComputeDMicroscopicCrossSection(tkin, Z, ep);
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}
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aaa += hhh;
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}
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cross *=hhh;
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if(cross < 0.0) cross = 0.0;
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return cross;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4MuPairProductionModel::ComputeDMicroscopicCrossSection(
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G4double tkin,
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G4double Z,
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G4double pairEnergy)
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// Calculates the differential (D) microscopic cross section
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// using the cross section formula of R.P. Kokoulin (18/01/98)
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{
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static const G4double
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xgi[] ={ 0.0199,0.1017,0.2372,0.4083,0.5917,0.7628,0.8983,0.9801 };
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static const G4double
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wgi[] ={ 0.0506,0.1112,0.1569,0.1813,0.1813,0.1569,0.1112,0.0506 };
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G4double cross = 0.;
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G4double particleMass = (G4MuonPlus::MuonPlus())->GetPDGMass();
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G4double totalEnergy = tkin + particleMass;
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G4double energyLoss = totalEnergy - pairEnergy;
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G4double a = 6.*particleMass*particleMass/(totalEnergy*energyLoss) ;
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G4double b = 4.*electron_mass_c2/pairEnergy;
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G4double tmn = (b+2.*a*(1.-b))/(1.+(1.-a)*sqrt(1.-b));
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if(tmn <= 0.) return cross;
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// G4cout << "a= " << a << " b= " << b << " tmn= " << tmn << G4endl;
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tmn = log(tmn);
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// G4cout << "a= " << a << " b= " << b << " tmn= " << tmn << G4endl;
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// Gaussian integration in ln(1-ro) ( with 8 points)
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for (G4int i=0; i<7; i++)
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{
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G4double ro = 1.-exp(tmn*xgi[i]) ;
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cross += wgi[i]*(1.-ro)*ComputeDDMicroscopicCrossSection(tkin,Z,pairEnergy,ro);
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// cout << "ro= " << ro << " cross= " << cross << endl;
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}
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cross *= -tmn ;
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return cross;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4MuPairProductionModel::ComputeDDMicroscopicCrossSection(
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G4double tkin,
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G4double Z,
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G4double pairEnergy,
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G4double asymmetry)
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// Calculates the differential (D) microscopic cross section
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// using the cross section formula of R.P. Kokoulin (18/01/98)
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{
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static const G4double sqrte = sqrt(exp(1.)) ;
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G4double bbbtf= 183. ;
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G4double bbbh = 202.4 ;
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G4double g1tf = 1.95e-5 ;
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G4double g2tf = 5.3e-5 ;
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G4double g1h = 4.4e-5 ;
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G4double g2h = 4.8e-5 ;
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G4double particleMass = (G4MuonPlus::MuonPlus())->GetPDGMass();
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G4double totalEnergy = tkin + particleMass;
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G4double energyLoss = totalEnergy - pairEnergy;
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G4double massratio = particleMass/electron_mass_c2 ;
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G4double massratio2 = massratio*massratio ;
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G4double z13 = pow(Z,0.333333333);
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G4double z23 = z13*z13 ;
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G4double c3 = 3.*sqrte*particleMass/4. ;
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G4double DDCrossSection = 0. ;
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if(energyLoss <= c3*z13) return DDCrossSection ;
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G4double c7 = 4.*electron_mass_c2 ;
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G4double c8 = 6.*particleMass*particleMass ;
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G4double alf = c7/pairEnergy ;
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G4double a3 = 1. - alf ;
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if(a3 <= 0.) return DDCrossSection ;
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// zeta calculation
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G4double bbb,g1,g2,zeta1,zeta2,zeta,z2 ;
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if( Z < 1.5 )
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{
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bbb = bbbh ;
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g1 = g1h ;
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g2 = g2h ;
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}
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else
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{
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bbb = bbbtf ;
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g1 = g1tf ;
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g2 = g2tf ;
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}
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zeta1 = 0.073 * log(totalEnergy/(particleMass+g1*z23*totalEnergy))-0.26 ;
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if( zeta1 > 0.)
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{
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zeta2 = 0.058*log(totalEnergy/(particleMass+g2*z13*totalEnergy))-0.14 ;
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zeta = zeta1/zeta2 ;
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}
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else
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{
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zeta = 0. ;
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}
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z2 = Z*(Z+zeta) ;
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G4double screen0 = 2.*electron_mass_c2*sqrte*bbb/(z13*pairEnergy) ;
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G4double a0 = totalEnergy*energyLoss ;
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G4double a1 = pairEnergy*pairEnergy/a0 ;
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G4double bet = 0.5*a1 ;
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G4double xi0 = 0.25*massratio2*a1 ;
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G4double del = c8/a0 ;
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G4double romin = 0. ;
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G4double romax = (1.-del)*sqrt(1.-c7/pairEnergy) ;
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if((asymmetry < romin) || (asymmetry > romax)) return DDCrossSection ;
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G4double a4 = 1.-asymmetry ;
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G4double a5 = a4*(2.-a4) ;
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G4double a6 = 1.-a5 ;
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G4double a7 = 1.+a6 ;
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G4double a9 = 3.+a6 ;
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G4double xi = xi0*a5 ;
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G4double xii = 1./xi ;
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G4double xi1 = 1.+xi ;
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G4double screen = screen0*xi1/a5 ;
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G4double yeu = 5.-a6+4.*bet*a7 ;
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G4double yed = 2.*(1.+3.*bet)*log(3.+xii)-a6-a1*(2.-a6) ;
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G4double yel = 1.+yeu/yed ;
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G4double ale=log(bbb/z13*sqrt(xi1*yel)/(1.+screen*yel)) ;
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G4double cre = 0.5*log(1.+2.25/(massratio2*z23)*xi1*yel) ;
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||||
G4double be ;
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if(xi <= 1.e3)
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be = ((2.+a6)*(1.+bet)+xi*a9)*log(1.+xii)+(a5-bet)/xi1-a9;
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||||
else
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||||
be = (3.-a6+a1*a7)/(2.+xi) ;
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||||
G4double fe = (ale-cre)*be ;
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if( fe < 0.)
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fe = 0. ;
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||||
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||||
G4double ymu = 4.+a6 +3.*bet*a7 ;
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||||
G4double ymd = a7*(1.5+a1)*log(3.+xi)+1.-1.5*a6 ;
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||||
G4double ym1 = 1.+ymu/ymd ;
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||||
G4double alm_crm = log(bbb*massratio/(1.5*z23*(1.+screen*ym1))) ;
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||||
G4double a10,bm ;
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||||
if( xi >= 1.e-3)
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||||
{
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||||
a10 = (1.+a1)*a5 ;
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||||
bm = (a7*(1.+1.5*bet)-a10*xii)*log(xi1)+xi*(a5-bet)/xi1+a10 ;
|
||||
}
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||||
else
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||||
bm = (5.-a6+bet*a9)*(xi/2.) ;
|
||||
G4double fm = alm_crm*bm ;
|
||||
if( fm < 0.)
|
||||
fm = 0. ;
|
||||
|
||||
DDCrossSection = (fe+fm/massratio2) ;
|
||||
|
||||
DDCrossSection *= 4.*fine_structure_const*fine_structure_const
|
||||
*classic_electr_radius*classic_electr_radius/(3.*pi) ;
|
||||
|
||||
DDCrossSection *= z2*energyLoss/(totalEnergy*pairEnergy) ;
|
||||
|
||||
|
||||
return DDCrossSection ;
|
||||
|
||||
}
|
||||
|
||||
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
||||
|
||||
G4double G4MuPairProductionModel::CrossSection(const G4Material* material,
|
||||
const G4ParticleDefinition* p,
|
||||
G4double kineticEnergy,
|
||||
G4double cutEnergy,
|
||||
G4double maxEnergy)
|
||||
{
|
||||
G4double cross = 0.0;
|
||||
if(!samplingTablesAreFilled) {
|
||||
minThreshold = MinEnergyCut(p, material);
|
||||
MakeSamplingTables();
|
||||
}
|
||||
G4double tmax = G4std::min(maxEnergy, kineticEnergy);
|
||||
G4double cut = G4std::max(cutEnergy, minThreshold);
|
||||
if(cut >= tmax) return cross;
|
||||
|
||||
const G4ElementVector* theElementVector = material->GetElementVector() ;
|
||||
const G4double* theAtomNumDensityVector = material->GetAtomicNumDensityVector();
|
||||
|
||||
if(material != oldMaterial) {
|
||||
oldMaterial = material;
|
||||
G4double fixedEnergy = sqrt(lowKinEnergy*highKinEnergy);
|
||||
ComputePartialSumSigma(material, fixedEnergy, cutEnergy);
|
||||
}
|
||||
|
||||
for (size_t i=0; i<material->GetNumberOfElements(); i++) {
|
||||
|
||||
G4double Z = (*theElementVector)[i]->GetZ();
|
||||
G4double A = (*theElementVector)[i]->GetA()/(g/mole) ;
|
||||
|
||||
G4double cr = ComputeMicroscopicCrossSection(kineticEnergy, Z, A, cutEnergy);
|
||||
|
||||
if(maxEnergy < kineticEnergy) {
|
||||
cr -= ComputeMicroscopicCrossSection(kineticEnergy, Z, A, maxEnergy);
|
||||
}
|
||||
cross += theAtomNumDensityVector[i] * cr;
|
||||
}
|
||||
|
||||
return cross;
|
||||
}
|
||||
|
||||
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
||||
|
||||
void G4MuPairProductionModel::ComputePartialSumSigma(const G4Material* material,
|
||||
G4double kineticEnergy,
|
||||
G4double cut)
|
||||
|
||||
// Build the table of cross section per element. The table is built for MATERIALS.
|
||||
// This table is used by DoIt to select randomly an element in the material.
|
||||
{
|
||||
size_t index = material->GetIndex();
|
||||
G4int nElements = material->GetNumberOfElements();
|
||||
const G4ElementVector* theElementVector = material->GetElementVector();
|
||||
const G4double* theAtomNumDensityVector = material->GetAtomicNumDensityVector();
|
||||
|
||||
G4DataVector* dv;
|
||||
|
||||
if (index >= partialSumSigma.size()) {
|
||||
|
||||
dv = new G4DataVector();
|
||||
partialSumSigma.push_back(dv);
|
||||
|
||||
} else {
|
||||
|
||||
dv = partialSumSigma[index];
|
||||
dv->clear();
|
||||
if(0 == index) samplingTablesAreFilled = false;
|
||||
}
|
||||
|
||||
G4double cross = 0.0;
|
||||
|
||||
for (G4int i=0; i<nElements; i++ ) {
|
||||
|
||||
G4double Z = (*theElementVector)[i]->GetZ();
|
||||
G4double A = (*theElementVector)[i]->GetA()/(g/mole) ;
|
||||
|
||||
cross += theAtomNumDensityVector[i] * ComputeMicroscopicCrossSection(kineticEnergy,
|
||||
Z, A, cut);
|
||||
dv->push_back(cross);
|
||||
}
|
||||
}
|
||||
|
||||
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
||||
|
||||
void G4MuPairProductionModel::MakeSamplingTables()
|
||||
{
|
||||
static const G4double sqrte = sqrt(exp(1.)) ;
|
||||
G4double particleMass = (G4MuonPlus::MuonPlus())->GetPDGMass();
|
||||
|
||||
for (G4int iz=0; iz<nzdat; iz++)
|
||||
{
|
||||
G4double atomicNumber = zdat[iz];
|
||||
G4double z13 = exp(log(atomicNumber)/3.) ;
|
||||
|
||||
for (G4int it=0; it<ntdat; it++)
|
||||
{
|
||||
G4double kineticEnergy = tdat[it];
|
||||
G4double maxPairEnergy = kineticEnergy+particleMass*(1.-0.75*sqrte*z13) ;
|
||||
|
||||
G4double CrossSection = 0.0 ;
|
||||
|
||||
G4double ymin = -5. ;
|
||||
G4double ymax = 0. ;
|
||||
G4double dy = (ymax-ymin)/NBIN ;
|
||||
|
||||
G4double y = ymin - 0.5*dy ;
|
||||
G4double yy = ymin - dy ;
|
||||
G4double x = exp(y);
|
||||
G4double fac = exp(dy);
|
||||
G4double dx = exp(yy)*(fac - 1.0);
|
||||
|
||||
if(maxPairEnergy > minThreshold) {
|
||||
G4double c = log(maxPairEnergy/minThreshold) ;
|
||||
|
||||
for (G4int i=0 ; i<NBIN; i++)
|
||||
{
|
||||
y += dy ;
|
||||
x *= fac;
|
||||
dx*= fac;
|
||||
G4double ep = minThreshold*exp(c*x) ;
|
||||
CrossSection += ep*dx*ComputeDMicroscopicCrossSection(
|
||||
kineticEnergy, atomicNumber, ep);
|
||||
ya[i]=y ;
|
||||
proba[iz][it][i] = CrossSection ;
|
||||
|
||||
}
|
||||
} else {
|
||||
|
||||
for (G4int i=0 ; i<NBIN; i++)
|
||||
{
|
||||
y += dy ;
|
||||
ya[i]=y ;
|
||||
proba[iz][it][i] = 0.0 ;
|
||||
}
|
||||
}
|
||||
|
||||
ya[NBIN]=0. ;
|
||||
|
||||
proba[iz][it][NBIN] = CrossSection ;
|
||||
|
||||
if(CrossSection > 0.)
|
||||
{
|
||||
for(G4int ib=0; ib<=NBIN; ib++)
|
||||
{
|
||||
proba[iz][it][ib] /= CrossSection ;
|
||||
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
samplingTablesAreFilled = true;
|
||||
}
|
||||
|
||||
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
||||
|
||||
G4std::vector<G4DynamicParticle*>* G4MuPairProductionModel::SampleSecondary(
|
||||
const G4Material* aMaterial,
|
||||
const G4DynamicParticle* aDynamicParticle,
|
||||
G4double minEnergy,
|
||||
G4double maxEnergy)
|
||||
{
|
||||
static const G4double esq = sqrt(exp(1.));
|
||||
G4double kineticEnergy = aDynamicParticle->GetKineticEnergy();
|
||||
G4double particleMass = aDynamicParticle->GetDefinition()->GetPDGMass();
|
||||
G4ParticleMomentum ParticleDirection =
|
||||
aDynamicParticle->GetMomentumDirection();
|
||||
|
||||
// select randomly one element constituing the material
|
||||
const G4Element* anElement = SelectRandomAtom(aMaterial);
|
||||
|
||||
// limits of the energy sampling
|
||||
G4double totalEnergy = kineticEnergy + particleMass ;
|
||||
//G4double TotalMomentum = sqrt(KineticEnergy*(TotalEnergy+particleMass)) ;
|
||||
G4double Z3 = anElement->GetIonisation()->GetZ3() ;
|
||||
G4double maxPairEnergy = totalEnergy-0.75*esq*particleMass*Z3 ;
|
||||
if(maxPairEnergy > maxEnergy) maxPairEnergy = maxEnergy;
|
||||
|
||||
// check against insufficient energy
|
||||
if(minEnergy >= maxPairEnergy) return 0;
|
||||
|
||||
// sample e-e+ energy, pair energy first
|
||||
G4double PairEnergy,x,yc,y ;
|
||||
// G4int iZ,iT;
|
||||
G4int iy ;
|
||||
|
||||
// select sampling table ;
|
||||
G4double lnZ = log(anElement->GetZ()) ;
|
||||
G4double delmin = 1.e10 ;
|
||||
G4double del ;
|
||||
G4int izz = 0;
|
||||
G4int itt = 0;
|
||||
G4int NBINminus1 = NBIN-1;
|
||||
for (G4int iz=0; iz<nzdat; iz++)
|
||||
{
|
||||
del = abs(lnZ-log(zdat[iz])) ;
|
||||
if(del<delmin)
|
||||
{
|
||||
delmin=del ;
|
||||
izz=iz ;
|
||||
}
|
||||
}
|
||||
delmin = 1.e10 ;
|
||||
for (G4int it=0; it<ntdat; it++)
|
||||
{
|
||||
del = abs(log(kineticEnergy)-log(tdat[it])) ;
|
||||
if(del<delmin)
|
||||
{
|
||||
delmin=del;
|
||||
itt=it ;
|
||||
}
|
||||
}
|
||||
|
||||
if( minEnergy <= minPairEnergy)
|
||||
iy = 0 ;
|
||||
else
|
||||
{
|
||||
G4double xc = log(minEnergy/minPairEnergy)/log(maxPairEnergy/minPairEnergy) ;
|
||||
yc = log(xc) ;
|
||||
|
||||
iy = -1 ;
|
||||
do {
|
||||
iy += 1 ;
|
||||
} while ((ya[iy] < yc )&&(iy < NBINminus1)) ;
|
||||
}
|
||||
|
||||
G4double norm = proba[izz][itt][iy] ;
|
||||
|
||||
G4double r = norm+G4UniformRand()*(1.-norm) ;
|
||||
|
||||
iy -= 1 ;
|
||||
do {
|
||||
iy += 1 ;
|
||||
} while ((proba[izz][itt][iy] < r)&&(iy < NBINminus1)) ;
|
||||
|
||||
//sampling is uniformly in y in the bin
|
||||
if( iy < NBIN )
|
||||
y = ya[iy] + G4UniformRand() * ( ya[iy+1] - ya[iy]) ;
|
||||
else
|
||||
y = ya[iy] ;
|
||||
|
||||
x = exp(y) ;
|
||||
|
||||
PairEnergy = minPairEnergy*exp(x*log(maxPairEnergy/minPairEnergy)) ;
|
||||
|
||||
// sample r=(E+-E-)/PairEnergy ( uniformly .....)
|
||||
G4double rmax = (1.-6.*particleMass*particleMass/(totalEnergy*
|
||||
(totalEnergy-PairEnergy)))
|
||||
*sqrt(1.-minPairEnergy/PairEnergy) ;
|
||||
r = rmax * (-1.+2.*G4UniformRand()) ;
|
||||
|
||||
// compute energies from PairEnergy,r
|
||||
G4double ElectronEnergy=(1.-r)*PairEnergy/2. ;
|
||||
G4double PositronEnergy=(1.+r)*PairEnergy/2. ;
|
||||
|
||||
// angles of the emitted particles ( Z - axis along the parent particle)
|
||||
// (mean theta for the moment)
|
||||
G4double Teta = electron_mass_c2/totalEnergy ;
|
||||
|
||||
G4double Phi = twopi * G4UniformRand() ;
|
||||
G4double dirx = sin(Teta)*cos(Phi) , diry = sin(Teta)*sin(Phi) ,
|
||||
dirz = cos(Teta) ;
|
||||
|
||||
G4double ElectronMomentum , PositronMomentum ;
|
||||
//G4double finalPx,finalPy,finalPz ;
|
||||
G4double ElectKineEnergy = ElectronEnergy - electron_mass_c2 ;
|
||||
|
||||
ElectronMomentum = sqrt(ElectKineEnergy*(ElectronEnergy+electron_mass_c2));
|
||||
G4ThreeVector ElectDirection ( dirx, diry, dirz );
|
||||
ElectDirection.rotateUz(ParticleDirection);
|
||||
|
||||
// create G4DynamicParticle object for the particle1
|
||||
G4DynamicParticle* aParticle1= new G4DynamicParticle();
|
||||
aParticle1->SetDefinition(G4Electron::Electron());
|
||||
aParticle1->SetMomentumDirection(ElectDirection);
|
||||
aParticle1->SetKineticEnergy(ElectKineEnergy);
|
||||
|
||||
|
||||
G4double PositKineEnergy = PositronEnergy - electron_mass_c2 ;
|
||||
PositronMomentum = sqrt(PositKineEnergy*(PositronEnergy+electron_mass_c2));
|
||||
|
||||
G4ThreeVector PositDirection ( -dirx, -diry, dirz );
|
||||
PositDirection.rotateUz(ParticleDirection);
|
||||
|
||||
// create G4DynamicParticle object for the particle2
|
||||
G4DynamicParticle* aParticle2= new G4DynamicParticle();
|
||||
aParticle2->SetDefinition(G4Positron::Positron());
|
||||
aParticle2->SetMomentumDirection(PositDirection);
|
||||
aParticle2->SetKineticEnergy(PositKineEnergy);
|
||||
|
||||
|
||||
G4std::vector<G4DynamicParticle*>* vdp = new G4std::vector<G4DynamicParticle*>;
|
||||
vdp->push_back(aParticle1);
|
||||
vdp->push_back(aParticle2);
|
||||
|
||||
return vdp;
|
||||
}
|
||||
|
||||
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
||||
|
||||
const G4Element* G4MuPairProductionModel::SelectRandomAtom(
|
||||
const G4Material* material) const
|
||||
{
|
||||
// select randomly 1 element within the material
|
||||
|
||||
G4int nElements = material->GetNumberOfElements();
|
||||
const G4ElementVector* theElementVector = material->GetElementVector();
|
||||
if(1 == nElements) return (*theElementVector)[0];
|
||||
else if(1 > nElements) return 0;
|
||||
|
||||
G4DataVector* dv = partialSumSigma[material->GetIndex()];
|
||||
G4double rval = G4UniformRand()*((*dv)[nElements-1]);
|
||||
for (G4int i=0; i<nElements; i++) {
|
||||
if (rval <= (*dv)[i]) return (*theElementVector)[i];
|
||||
}
|
||||
return (*theElementVector)[nElements-1];
|
||||
}
|
||||
|
||||
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
||||
|
||||
|
||||
Reference in New Issue
Block a user