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geant4/source/processes/hadronic/models/lepto_nuclear/src/G4MuonVDNuclearModel.cc
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Gabriele Cosmo b3bf75a2a1 Import Geant4 11.0.2 source tree
2022-05-25 15:50:57 +02:00

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//
// ********************************************************************
// * License and Disclaimer *
// * *
// * The Geant4 software is copyright of the Copyright Holders of *
// * the Geant4 Collaboration. It is provided under the terms and *
// * conditions of the Geant4 Software License, included in the file *
// * LICENSE and available at http://cern.ch/geant4/license . These *
// * include a list of copyright holders. *
// * *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work make any representation or warranty, express or implied, *
// * regarding this software system or assume any liability for its *
// * use. Please see the license in the file LICENSE and URL above *
// * for the full disclaimer and the limitation of liability. *
// * *
// * This code implementation is the result of the scientific and *
// * technical work of the GEANT4 collaboration. *
// * By using, copying, modifying or distributing the software (or *
// * any work based on the software) you agree to acknowledge its *
// * use in resulting scientific publications, and indicate your *
// * acceptance of all terms of the Geant4 Software license. *
// ********************************************************************
//
//
// Author: D.H. Wright
// Date: 2 February 2011
//
// Description: model of muon nuclear interaction in which a gamma from
// the virtual photon spectrum interacts in the nucleus as
// a real gamma at low energies and as a pi0 at high energies.
// Kokoulin's muon cross section and equivalent gamma spectrum
// are used.
//
#include "G4MuonVDNuclearModel.hh"
#include "Randomize.hh"
#include "G4Log.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4CascadeInterface.hh"
#include "G4TheoFSGenerator.hh"
#include "G4GeneratorPrecompoundInterface.hh"
#include "G4PreCompoundModel.hh"
#include "G4LundStringFragmentation.hh"
#include "G4ExcitedStringDecay.hh"
#include "G4FTFModel.hh"
#include "G4HadronicInteractionRegistry.hh"
#include "G4KokoulinMuonNuclearXS.hh"
#include "G4CrossSectionDataSetRegistry.hh"
#include "G4ElementData.hh"
#include "G4Physics2DVector.hh"
#include "G4Pow.hh"
#include "G4PhysicsModelCatalog.hh"
const G4int G4MuonVDNuclearModel::zdat[] = {1, 4, 13, 29, 92};
const G4double G4MuonVDNuclearModel::adat[] = {1.01,9.01,26.98,63.55,238.03};
const G4double G4MuonVDNuclearModel::tdat[] = {
1.e3,2.e3,3.e3,4.e3,5.e3,6.e3,7.e3,8.e3,9.e3,
1.e4,2.e4,3.e4,4.e4,5.e4,6.e4,7.e4,8.e4,9.e4,
1.e5,2.e5,3.e5,4.e5,5.e5,6.e5,7.e5,8.e5,9.e5,
1.e6,2.e6,3.e6,4.e6,5.e6,6.e6,7.e6,8.e6,9.e6,
1.e7,2.e7,3.e7,4.e7,5.e7,6.e7,7.e7,8.e7,9.e7,
1.e8,2.e8,3.e8,4.e8,5.e8,6.e8,7.e8,8.e8,9.e8,
1.e9,2.e9,3.e9,4.e9,5.e9,6.e9,7.e9,8.e9,9.e9,
1.e10,2.e10,3.e10,4.e10,5.e10,6.e10,7.e10,8.e10,9.e10,1.e11};
G4ElementData* G4MuonVDNuclearModel::fElementData = nullptr;
G4MuonVDNuclearModel::G4MuonVDNuclearModel()
: G4HadronicInteraction("G4MuonVDNuclearModel"),isMaster(false)
{
muNucXS = (G4KokoulinMuonNuclearXS*)G4CrossSectionDataSetRegistry::Instance()->
GetCrossSectionDataSet(G4KokoulinMuonNuclearXS::Default_Name());
SetMinEnergy(0.0);
SetMaxEnergy(1*CLHEP::PeV);
CutFixed = 0.2*CLHEP::GeV;
if(!fElementData && G4Threading::IsMasterThread()) {
fElementData = new G4ElementData();
MakeSamplingTable();
isMaster = true;
}
// reuse existing pre-compound model
G4GeneratorPrecompoundInterface* precoInterface
= new G4GeneratorPrecompoundInterface();
G4HadronicInteraction* p =
G4HadronicInteractionRegistry::Instance()->FindModel("PRECO");
G4VPreCompoundModel* pre = static_cast<G4VPreCompoundModel*>(p);
if(!pre) { pre = new G4PreCompoundModel(); }
precoInterface->SetDeExcitation(pre);
// Build FTFP model
ftfp = new G4TheoFSGenerator();
ftfp->SetTransport(precoInterface);
theFragmentation = new G4LundStringFragmentation();
theStringDecay = new G4ExcitedStringDecay(theFragmentation);
G4FTFModel* theStringModel = new G4FTFModel;
theStringModel->SetFragmentationModel(theStringDecay);
ftfp->SetHighEnergyGenerator(theStringModel);
// Build Bertini cascade
bert = new G4CascadeInterface();
// Creator model ID
secID = G4PhysicsModelCatalog::GetModelID( "model_" + GetModelName() );
}
G4MuonVDNuclearModel::~G4MuonVDNuclearModel()
{
delete theFragmentation;
delete theStringDecay;
if(isMaster) {
delete fElementData;
fElementData = nullptr;
}
}
G4HadFinalState*
G4MuonVDNuclearModel::ApplyYourself(const G4HadProjectile& aTrack,
G4Nucleus& targetNucleus)
{
theParticleChange.Clear();
// For very low energy, return initial track
G4double epmax = aTrack.GetTotalEnergy() - 0.5*proton_mass_c2;
if (epmax <= CutFixed) {
theParticleChange.SetStatusChange(isAlive);
theParticleChange.SetEnergyChange(aTrack.GetKineticEnergy());
theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
return &theParticleChange;
}
// Produce recoil muon and transferred photon
G4DynamicParticle* transferredPhoton = CalculateEMVertex(aTrack, targetNucleus);
// Interact the gamma with the nucleus
CalculateHadronicVertex(transferredPhoton, targetNucleus);
return &theParticleChange;
}
G4DynamicParticle*
G4MuonVDNuclearModel::CalculateEMVertex(const G4HadProjectile& aTrack,
G4Nucleus& targetNucleus)
{
// Select sampling table
G4double KineticEnergy = aTrack.GetKineticEnergy();
G4double TotalEnergy = aTrack.GetTotalEnergy();
G4double Mass = G4MuonMinus::MuonMinus()->GetPDGMass();
G4Pow* g4calc = G4Pow::GetInstance();
G4double lnZ = g4calc->logZ(targetNucleus.GetZ_asInt());
G4double epmin = CutFixed;
G4double epmax = TotalEnergy - 0.5*proton_mass_c2;
G4double m0 = CutFixed;
G4double delmin = 1.e10;
G4double del;
G4int izz = 0;
G4int itt = 0;
for (G4int iz = 0; iz < nzdat; ++iz) {
del = std::abs(lnZ - g4calc->logZ(zdat[iz]));
if (del < delmin) {
delmin = del;
izz = iz;
}
}
delmin = 1.e10;
for (G4int it = 0; it < ntdat; ++it) {
del = std::abs(G4Log(KineticEnergy)-G4Log(tdat[it]) );
if (del < delmin) {
delmin = del;
itt = it;
}
}
// Sample the energy transfer according to the probability table
G4double r = G4UniformRand();
G4int iy;
G4int Z = zdat[izz];
for(iy = 0; iy<NBIN; ++iy) {
G4double pvv = fElementData->GetElement2DData(Z)->GetValue(iy, itt);
if(pvv >= r) { break; }
}
// Sampling is done uniformly in y in the bin
G4double pvx = fElementData->GetElement2DData(Z)->GetX(iy);
G4double pvx1 = fElementData->GetElement2DData(Z)->GetX(iy+1);
G4double y = pvx + G4UniformRand() * (pvx1 - pvx);
G4double x = G4Exp(y);
G4double ep = epmin*G4Exp(x*G4Log(epmax/epmin) );
// Sample scattering angle of mu, but first t should be sampled.
G4double yy = ep/TotalEnergy;
G4double tmin = Mass*Mass*yy*yy/(1.-yy);
G4double tmax = 2.*proton_mass_c2*ep;
G4double t1;
G4double t2;
if (m0 < ep) {
t1 = m0*m0;
t2 = ep*ep;
} else {
t1 = ep*ep;
t2 = m0*m0;
}
G4double w1 = tmax*t1;
G4double w2 = tmax+t1;
G4double w3 = tmax*(tmin+t1)/(tmin*w2);
G4double y1 = 1.-yy;
G4double y2 = 0.5*yy*yy;
G4double y3 = y1+y2;
G4double t = 0.0;
G4double rej = 0.0;
// Now sample t
G4int ntry = 0;
do
{
ntry += 1;
if (ntry > 10000) {
G4ExceptionDescription eda;
eda << " While count exceeded " << G4endl;
G4Exception("G4MuonVDNuclearModel::CalculateEMVertex()", "HAD_RPG_100", JustWarning, eda);
break;
}
t = w1/(w2*G4Exp(G4UniformRand()*G4Log(w3))-tmax);
rej = (1.-t/tmax)*(y1*(1.-tmin/t)+y2)/(y3*(1.-t/t2));
} while (G4UniformRand() > rej) ; /* Loop checking, 01.09.2015, D.Wright */
// compute angle from t
G4double sinth2 =
0.5*(t-tmin)/(2.*(TotalEnergy*(TotalEnergy-ep)-Mass*Mass)-tmin);
G4double theta = std::acos(1. - 2.*sinth2);
G4double phi = twopi*G4UniformRand();
G4double sinth = std::sin(theta);
G4double dirx = sinth*std::cos(phi);
G4double diry = sinth*std::sin(phi);
G4double dirz = std::cos(theta);
G4ThreeVector finalDirection(dirx,diry,dirz);
G4ThreeVector ParticleDirection(aTrack.Get4Momentum().vect().unit() );
finalDirection.rotateUz(ParticleDirection);
G4double NewKinEnergy = KineticEnergy - ep;
G4double finalMomentum = std::sqrt(NewKinEnergy*(NewKinEnergy+2.*Mass) );
G4double Ef = NewKinEnergy + Mass;
G4double initMomentum = std::sqrt(KineticEnergy*(TotalEnergy+Mass) );
// Set energy and direction of scattered primary in theParticleChange
theParticleChange.SetStatusChange(isAlive);
theParticleChange.SetEnergyChange(NewKinEnergy);
theParticleChange.SetMomentumChange(finalDirection);
// Now create the emitted gamma
G4LorentzVector primaryMomentum(initMomentum*ParticleDirection, TotalEnergy);
G4LorentzVector fsMomentum(finalMomentum*finalDirection, Ef);
G4LorentzVector momentumTransfer = primaryMomentum - fsMomentum;
G4DynamicParticle* gamma =
new G4DynamicParticle(G4Gamma::Gamma(), momentumTransfer);
return gamma;
}
void
G4MuonVDNuclearModel::CalculateHadronicVertex(G4DynamicParticle* incident,
G4Nucleus& target)
{
G4HadFinalState* hfs = 0;
G4double gammaE = incident->GetTotalEnergy();
if (gammaE < 10*GeV) {
G4HadProjectile projectile(*incident);
hfs = bert->ApplyYourself(projectile, target);
} else {
// convert incident gamma to a pi0
G4double piMass = G4PionZero::PionZero()->GetPDGMass();
G4double piKE = incident->GetTotalEnergy() - piMass;
G4double piMom = std::sqrt(piKE*(piKE + 2*piMass) );
G4ThreeVector piMomentum(incident->GetMomentumDirection() );
piMomentum *= piMom;
G4DynamicParticle theHadron(G4PionZero::PionZero(), piMomentum);
G4HadProjectile projectile(theHadron);
hfs = ftfp->ApplyYourself(projectile, target);
}
delete incident;
// Assign the creator model ID to the secondaries
for ( size_t i = 0; i < hfs->GetNumberOfSecondaries(); ++i ) {
hfs->GetSecondary( i )->SetCreatorModelID( secID );
}
// Copy secondaries from sub-model to model
theParticleChange.AddSecondaries(hfs);
}
void G4MuonVDNuclearModel::MakeSamplingTable()
{
G4int nbin;
G4double KineticEnergy;
G4double TotalEnergy;
G4double Maxep;
G4double CrossSection;
G4double c;
G4double y;
G4double ymin,ymax;
G4double dy,yy;
G4double dx,x;
G4double ep;
G4double AtomicNumber;
G4double AtomicWeight;
G4double mumass = G4MuonMinus::MuonMinus()->GetPDGMass();
for (G4int iz = 0; iz < nzdat; ++iz) {
AtomicNumber = zdat[iz];
AtomicWeight = adat[iz]*(g/mole);
G4Physics2DVector* pv = new G4Physics2DVector(NBIN+1,ntdat+1);
G4double pvv;
for (G4int it = 0; it < ntdat; ++it) {
KineticEnergy = tdat[it];
TotalEnergy = KineticEnergy + mumass;
Maxep = TotalEnergy - 0.5*proton_mass_c2;
CrossSection = 0.0;
// Calculate the differential cross section
// numerical integration in log .........
c = G4Log(Maxep/CutFixed);
ymin = -5.0;
ymax = 0.0;
dy = (ymax-ymin)/NBIN;
nbin=-1;
y = ymin - 0.5*dy;
yy = ymin - dy;
for (G4int i = 0; i < NBIN; ++i) {
y += dy;
x = G4Exp(y);
yy += dy;
dx = G4Exp(yy+dy)-G4Exp(yy);
ep = CutFixed*G4Exp(c*x);
CrossSection +=
ep*dx*muNucXS->ComputeDDMicroscopicCrossSection(KineticEnergy,
AtomicNumber,
AtomicWeight, ep);
if (nbin < NBIN) {
++nbin;
pv->PutValue(nbin, it, CrossSection);
pv->PutX(nbin, y);
}
}
pv->PutX(NBIN, 0.);
if (CrossSection > 0.0) {
for (G4int ib = 0; ib <= nbin; ++ib) {
pvv = pv->GetValue(ib, it);
pvv = pvv/CrossSection;
pv->PutValue(ib, it, pvv);
}
}
} // loop on it
fElementData->InitialiseForElement(zdat[iz], pv);
} // loop on iz
// G4cout << " Kokoulin XS = "
// << muNucXS->ComputeDDMicroscopicCrossSection(1*GeV, 20.0,
// 40.0*g/mole, 0.3*GeV)/millibarn
// << G4endl;
}
void G4MuonVDNuclearModel::ModelDescription(std::ostream& outFile) const
{
outFile << "G4MuonVDNuclearModel handles the inelastic scattering\n"
<< "of mu- and mu+ from nuclei using the equivalent photon\n"
<< "approximation in which the incoming lepton generates a\n"
<< "virtual photon at the electromagnetic vertex, and the\n"
<< "virtual photon is converted to a real photon. At low\n"
<< "energies, the photon interacts directly with the nucleus\n"
<< "using the Bertini cascade. At high energies the photon\n"
<< "is converted to a pi0 which interacts using the FTFP\n"
<< "model. The muon-nuclear cross sections of R. Kokoulin \n"
<< "are used to generate the virtual photon spectrum\n";
}
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