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This commit is contained in:
Gabriele Cosmo
2016-06-09 16:25:56 +02:00
parent 74cad5e589
commit 89a9605df1
4440 changed files with 379508 additions and 189225 deletions
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source/processes/electromagnetic/standard/src/G4eCoulombScatteringModel.cc
+58 -189
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@@ -23,8 +23,8 @@
// * acceptance of all terms of the Geant4 Software license. *
// ********************************************************************
//
// $Id: G4eCoulombScatteringModel.cc,v 1.78 2009/10/28 10:14:13 vnivanch Exp $
// GEANT4 tag $Name: geant4-09-03 $
// $Id: G4eCoulombScatteringModel.cc,v 1.91 2010/11/13 18:45:55 vnivanch Exp $
// GEANT4 tag $Name: geant4-09-04 $
//
// -------------------------------------------------------------------
//
@@ -46,6 +46,8 @@
// 09.10.07 V.Ivanchenko reorganized methods, add cut dependence in scattering off e-
// 09.06.08 V.Ivanchenko add SelectIsotope and sampling of the recoil ion
// 16.06.09 C.Consolandi fixed computation of effective mass
// 27.05.10 V.Ivanchenko added G4WentzelOKandVIxSection class to
// compute cross sections and sample scattering angle
//
//
// Class Description:
@@ -59,69 +61,50 @@
#include "Randomize.hh"
#include "G4DataVector.hh"
#include "G4ElementTable.hh"
#include "G4PhysicsLogVector.hh"
#include "G4ParticleChangeForGamma.hh"
#include "G4Electron.hh"
#include "G4Positron.hh"
#include "G4Proton.hh"
#include "G4ParticleTable.hh"
#include "G4ProductionCutsTable.hh"
#include "G4NucleiProperties.hh"
#include "G4Pow.hh"
#include "G4LossTableManager.hh"
#include "G4NistManager.hh"
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
G4double G4eCoulombScatteringModel::ScreenRSquare[] = {0.0};
G4double G4eCoulombScatteringModel::FormFactor[] = {0.0};
using namespace std;
G4eCoulombScatteringModel::G4eCoulombScatteringModel(const G4String& nam)
: G4VEmModel(nam),
cosThetaMin(1.0),
cosThetaMax(-1.0),
q2Limit(TeV*TeV),
alpha2(fine_structure_const*fine_structure_const),
faclim(100.0),
isInitialised(false)
{
fNistManager = G4NistManager::Instance();
theParticleTable = G4ParticleTable::GetParticleTable();
theElectron = G4Electron::Electron();
thePositron = G4Positron::Positron();
theProton = G4Proton::Proton();
currentMaterial = 0;
currentElement = 0;
lowEnergyLimit = 0.1*keV;
G4double p0 = electron_mass_c2*classic_electr_radius;
coeff = twopi*p0*p0;
tkin = targetZ = mom2 = DBL_MIN;
elecXSection = nucXSection = 0.0;
lowEnergyLimit = 1*eV;
recoilThreshold = 0.*keV;
ecut = DBL_MAX;
particle = 0;
currentCouple = 0;
wokvi = new G4WentzelOKandVIxSection();
// Thomas-Fermi screening radii
// Formfactors from A.V. Butkevich et al., NIM A 488 (2002) 282
currentMaterialIndex = 0;
if(0.0 == ScreenRSquare[0]) {
G4double a0 = electron_mass_c2/0.88534;
G4double constn = 6.937e-6/(MeV*MeV);
ScreenRSquare[0] = alpha2*a0*a0;
for(G4int j=1; j<100; j++) {
G4double x = a0*fNistManager->GetZ13(j);
ScreenRSquare[j] = alpha2*x*x;
x = fNistManager->GetA27(j);
FormFactor[j] = constn*x*x;
}
}
cosTetMinNuc = 1.0;
cosTetMaxNuc = -1.0;
elecRatio = 0.0;
mass = proton_mass_c2;
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
G4eCoulombScatteringModel::~G4eCoulombScatteringModel()
{}
{
delete wokvi;
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
@@ -130,10 +113,14 @@ void G4eCoulombScatteringModel::Initialise(const G4ParticleDefinition* p,
{
SetupParticle(p);
currentCouple = 0;
elecXSection = nucXSection = 0.0;
tkin = targetZ = mom2 = DBL_MIN;
ecut = etag = DBL_MAX;
cosThetaMin = cos(PolarAngleLimit());
wokvi->Initialise(p, cosThetaMin);
/*
G4cout << "G4eCoulombScatteringModel: factorA2(GeV^2) = " << factorA2/(GeV*GeV)
<< " 1-cos(ThetaLimit)= " << 1 - cosThetaMin
<< " cos(thetaMax)= " << cosThetaMax
<< G4endl;
*/
pCuts = G4ProductionCutsTable::GetProductionCutsTable()->GetEnergyCutsVector(3);
//G4cout << "!!! G4eCoulombScatteringModel::Initialise for "
// << p->GetParticleName() << " cos(TetMin)= " << cosThetaMin
@@ -150,36 +137,6 @@ void G4eCoulombScatteringModel::Initialise(const G4ParticleDefinition* p,
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
void G4eCoulombScatteringModel::ComputeMaxElectronScattering(G4double cutEnergy)
{
ecut = cutEnergy;
G4double tmax = tkin;
cosTetMaxElec = 1.0;
if(mass > MeV) {
G4double ratio = electron_mass_c2/mass;
G4double tau = tkin/mass;
tmax = 2.0*electron_mass_c2*tau*(tau + 2.)/
(1.0 + 2.0*ratio*(tau + 1.0) + ratio*ratio);
cosTetMaxElec = 1.0 - std::min(cutEnergy, tmax)*electron_mass_c2/mom2;
} else {
if(particle == theElectron) tmax *= 0.5;
G4double t = std::min(cutEnergy, tmax);
G4double mom21 = t*(t + 2.0*electron_mass_c2);
G4double t1 = tkin - t;
//G4cout << "tkin= " << tkin << " t= " << t << " t1= " << t1 << G4endl;
if(t1 > 0.0) {
G4double mom22 = t1*(t1 + 2.0*mass);
G4double ctm = (mom2 + mom22 - mom21)*0.5/sqrt(mom2*mom22);
//G4cout << "ctm= " << ctm << G4endl;
if(ctm < 1.0) cosTetMaxElec = ctm;
if(ctm < -1.0) cosTetMaxElec = -1.0;
}
}
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
G4double G4eCoulombScatteringModel::ComputeCrossSectionPerAtom(
const G4ParticleDefinition* p,
G4double kinEnergy,
@@ -189,72 +146,35 @@ G4double G4eCoulombScatteringModel::ComputeCrossSectionPerAtom(
//G4cout << "### G4eCoulombScatteringModel::ComputeCrossSectionPerAtom for "
// << p->GetParticleName()<<" Z= "<<Z<<" e(MeV)= "<< kinEnergy/MeV << G4endl;
G4double xsec = 0.0;
SetupParticle(p);
if(kinEnergy < lowEnergyLimit) return xsec;
SetupKinematic(kinEnergy, cutEnergy);
if(cosTetMaxNuc < cosTetMinNuc) {
SetupTarget(Z, kinEnergy);
xsec = CrossSectionPerAtom();
if(p != particle) { SetupParticle(p); }
// cross section is set to zero to avoid problems in sample secondary
if(kinEnergy < lowEnergyLimit) { return xsec; }
DefineMaterial(CurrentCouple());
cosTetMinNuc = wokvi->SetupKinematic(kinEnergy, currentMaterial);
if(cosThetaMax < cosTetMinNuc) {
G4int iz = G4int(Z);
cosTetMinNuc = wokvi->SetupTarget(iz, cutEnergy);
cosTetMaxNuc = cosThetaMax;
if(iz == 1 && cosTetMaxNuc < 0.0 && particle == theProton) {
cosTetMaxNuc = 0.0;
}
xsec = wokvi->ComputeNuclearCrossSection(cosTetMinNuc, cosTetMaxNuc);
elecRatio = wokvi->ComputeElectronCrossSection(cosTetMinNuc, cosThetaMax);
xsec += elecRatio;
if(xsec > 0.0) { elecRatio /= xsec; }
}
/*
G4cout << "e(MeV)= " << ekin/MeV << "cosTetMinNuc= " << cosTetMinNuc
<< " cosTetMaxNuc= " << cosTetMaxNuc
<< " cosTetMaxElec= " << cosTetMaxElec
G4cout << "e(MeV)= " << kinEnergy/MeV << " xsec(b)= " << xsec/barn
<< " 1-cosTetMinNuc= " << 1-cosTetMinNuc
<< " 1-cosTetMaxNuc2= " << 1-cosTetMaxNuc2
<< " 1-cosTetMaxElec= " << 1-cosTetMaxElec
<< " screenZ= " << screenZ
<< " formfactA= " << formfactA << G4endl;
*/
return xsec;
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
G4double G4eCoulombScatteringModel::CrossSectionPerAtom()
{
// This method needs initialisation before be called
//G4double fac = coeff*targetZ*chargeSquare*invbeta2/mom2;
G4double meff = targetMass/(mass+targetMass);
G4double fac = coeff*targetZ*chargeSquare*invbeta2/(mom2*meff*meff);
elecXSection = 0.0;
nucXSection = 0.0;
G4double x = 1.0 - cosTetMinNuc;
G4double x1 = x + screenZ;
if(cosTetMaxElec2 < cosTetMinNuc) {
elecXSection = fac*(cosTetMinNuc - cosTetMaxElec2)/
(x1*(1.0 - cosTetMaxElec2 + screenZ));
nucXSection = elecXSection;
}
//G4cout << "XS tkin(MeV)= " << tkin<<" xs= " <<nucXSection
// << " costmax= " << cosTetMaxNuc2
// << " costmin= " << cosTetMinNuc << " Z= " << targetZ <<G4endl;
if(cosTetMaxNuc2 < cosTetMinNuc) {
G4double s = screenZ*formfactA;
G4double z1 = 1.0 - cosTetMaxNuc2 + screenZ;
G4double s1 = 1.0 - s;
G4double d = s1/formfactA;
//G4cout <<"x1= "<<x1<<" z1= " <<z1<<" s= "<<s << " d= " <<d <<G4endl;
if(d < 0.2*x1) {
G4double x2 = x1*x1;
G4double z2 = z1*z1;
x = (1.0/(x1*x2) - 1.0/(z1*z2) - d*1.5*(1.0/(x2*x2) - 1.0/(z2*z2)))/
(3.0*formfactA*formfactA);
} else {
G4double x2 = x1 + d;
G4double z2 = z1 + d;
x = (1.0/x1 - 1.0/z1 + 1.0/x2 - 1.0/z2 - 2.0*log(z1*x2/(z2*x1))/d)/(s1*s1);
}
nucXSection += fac*targetZ*x;
}
//G4cout<<" cross(bn)= "<<nucXSection/barn<<" xsElec(bn)= "<<elecXSection/barn
// << " Asc= " << screenZ << G4endl;
return nucXSection;
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
void G4eCoulombScatteringModel::SampleSecondaries(
@@ -265,11 +185,9 @@ void G4eCoulombScatteringModel::SampleSecondaries(
G4double)
{
G4double kinEnergy = dp->GetKineticEnergy();
if(kinEnergy < lowEnergyLimit) return;
DefineMaterial(couple);
if(kinEnergy < lowEnergyLimit) { return; }
SetupParticle(dp->GetDefinition());
SetupKinematic(kinEnergy, cutEnergy);
//G4cout << "G4eCoulombScatteringModel::SampleSecondaries e(MeV)= "
// << kinEnergy << " " << particle->GetParticleName()
// << " cut= " << cutEnergy<< G4endl;
@@ -278,32 +196,29 @@ void G4eCoulombScatteringModel::SampleSecondaries(
currentElement = SelectRandomAtom(couple,particle,
kinEnergy,cutEnergy,kinEnergy);
SetupTarget(currentElement->GetZ(),kinEnergy);
G4double Z = currentElement->GetZ();
if(ComputeCrossSectionPerAtom(particle,kinEnergy, Z,
kinEnergy, cutEnergy, kinEnergy) == 0.0)
{ return; }
G4int iz = G4int(Z);
G4int ia = SelectIsotopeNumber(currentElement);
targetMass = G4NucleiProperties::GetNuclearMass(ia, iz);
G4double cost = SampleCosineTheta();
G4double z1 = 1.0 - cost;
if(z1 < 0.0) return;
G4double targetMass = G4NucleiProperties::GetNuclearMass(ia, iz);
G4double sint = sqrt(z1*(1.0 + cost));
//G4cout<<"## Sampled sint= " << sint << " Z= " << targetZ << " A= " << ia
// << " screenZ= " << screenZ << " cn= " << formfactA << G4endl;
G4double phi = twopi * G4UniformRand();
G4ThreeVector newDirection =
wokvi->SampleSingleScattering(cosTetMinNuc, cosThetaMax, elecRatio);
G4double cost = newDirection.z();
G4ThreeVector direction = dp->GetMomentumDirection();
G4ThreeVector newDirection(cos(phi)*sint,sin(phi)*sint,cost);
newDirection.rotateUz(direction);
fParticleChange->ProposeMomentumDirection(newDirection);
// recoil sampling assuming a small recoil
// and first order correction to primary 4-momentum
G4double q2 = 2*z1*mom2;
G4double trec = q2/(sqrt(targetMass*targetMass + q2) + targetMass);
G4double mom2 = wokvi->GetMomentumSquare();
G4double trec = mom2*(1.0 - cost)/(targetMass + (mass + kinEnergy)*(1.0 - cost));
G4double finalT = kinEnergy - trec;
//G4cout<<"G4eCoulombScatteringModel: finalT= "<<finalT<<" Trec= "<<trec<<G4endl;
if(finalT <= lowEnergyLimit) {
@@ -331,50 +246,4 @@ void G4eCoulombScatteringModel::SampleSecondaries(
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
G4double G4eCoulombScatteringModel::SampleCosineTheta()
{
G4double costm = cosTetMaxNuc2;
G4double formf = formfactA;
G4double prob = 0.0;
G4double xs = CrossSectionPerAtom();
if(xs > 0.0) prob = elecXSection/xs;
// scattering off e or A?
if(G4UniformRand() < prob) {
costm = cosTetMaxElec2;
formf = 0.0;
}
/*
G4cout << "SampleCost: e(MeV)= " << tkin
<< " 1-ctmaxN= " << 1. - cosTetMinNuc
<< " 1-ctmax= " << 1. - costm
<< " Z= " << targetZ
<< G4endl;
*/
if(costm >= cosTetMinNuc) return 2.0;
G4double x1 = 1. - cosTetMinNuc + screenZ;
G4double x2 = 1. - costm + screenZ;
G4double x3 = cosTetMinNuc - costm;
G4double grej, z1;
do {
z1 = x1*x2/(x1 + G4UniformRand()*x3) - screenZ;
grej = 1.0/(1.0 + formf*z1);
} while ( G4UniformRand() > grej*grej );
if(mass > MeV) {
if(G4UniformRand() > (1. - z1*0.5)/(1.0 + z1*sqrt(mom2)/targetMass)) {
return 2.0;
}
}
//G4cout << "z1= " << z1 << " cross= " << nucXSection/barn
// << " crossE= " << elecXSection/barn << G4endl;
return 1.0 - z1;
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......