Gabriele Cosmo
313 lines
12 KiB
C++
313 lines
12 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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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. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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// $Id: G4eplusPolarizedAnnihilation.cc,v 1.3 2006/11/17 14:14:22 vnivanch Exp $
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// GEANT4 tag $Name: geant4-08-02 $
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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: G4eplusPolarizedAnnihilation
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//
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// Author: A. Schaelicke on base of Vladimir Ivanchenko / Michel Maire code
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//
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// Creation date: 02.07.2006
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//
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// Modifications:
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// 26-07-06 modified cross section (P. Starovoitov)
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// 21-08-06 interface updated (A. Schaelicke)
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//
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//
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// Class Description:
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//
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// Polarized process of e+ annihilation into 2 gammas
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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 "G4eplusPolarizedAnnihilation.hh"
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#include "G4MaterialCutsCouple.hh"
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#include "G4Gamma.hh"
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#include "G4PhysicsVector.hh"
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#include "G4PhysicsLogVector.hh"
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#include "G4PolarizedAnnihilationModel.hh"
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#include "G4PhysicsTableHelper.hh"
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#include "G4ProductionCutsTable.hh"
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#include "G4PolarizationManager.hh"
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#include "G4PolarizationHelper.hh"
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#include "G4StokesVector.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4eplusPolarizedAnnihilation::G4eplusPolarizedAnnihilation(const G4String& name)
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: G4VEmProcess(name), isInitialised(false),
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theAsymmetryTable(NULL),
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theTransverseAsymmetryTable(NULL)
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{}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4eplusPolarizedAnnihilation::~G4eplusPolarizedAnnihilation()
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{
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if (theAsymmetryTable) {
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theAsymmetryTable->clearAndDestroy();
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delete theAsymmetryTable;
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}
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if (theTransverseAsymmetryTable) {
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theTransverseAsymmetryTable->clearAndDestroy();
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delete theTransverseAsymmetryTable;
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4eplusPolarizedAnnihilation::InitialiseProcess(const G4ParticleDefinition*)
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{
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if(!isInitialised) {
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isInitialised = true;
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// SetVerboseLevel(3);
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SetBuildTableFlag(true);
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SetStartFromNullFlag(false);
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SetSecondaryParticle(G4Gamma::Gamma());
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G4double emin = 0.1*keV;
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G4double emax = 100.*TeV;
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SetLambdaBinning(120);
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SetMinKinEnergy(emin);
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SetMaxKinEnergy(emax);
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emModel = new G4PolarizedAnnihilationModel();
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emModel->SetLowEnergyLimit(emin);
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emModel->SetHighEnergyLimit(emax);
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AddEmModel(1, emModel);
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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// for polarization
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G4double G4eplusPolarizedAnnihilation::GetMeanFreePath(const G4Track& track,
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G4double previousStepSize,
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G4ForceCondition* condition)
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{
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G4double mfp = G4VEmProcess::GetMeanFreePath(track, previousStepSize, condition);
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if (theAsymmetryTable) {
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G4Material* aMaterial = track.GetMaterial();
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G4VPhysicalVolume* aPVolume = track.GetVolume();
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G4LogicalVolume* aLVolume = aPVolume->GetLogicalVolume();
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// G4Material* bMaterial = aLVolume->GetMaterial();
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G4PolarizationManager * polarizationManger = G4PolarizationManager::GetInstance();
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const G4bool volumeIsPolarized = polarizationManger->IsPolarized(aLVolume);
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G4StokesVector electronPolarization = polarizationManger->GetVolumePolarization(aLVolume);
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if (!volumeIsPolarized || mfp == DBL_MAX) return mfp;
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// *** get asymmetry, if target is polarized ***
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const G4DynamicParticle* aDynamicPositron = track.GetDynamicParticle();
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const G4double positronEnergy = aDynamicPositron->GetKineticEnergy();
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const G4StokesVector positronPolarization = track.GetPolarization();
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const G4ParticleMomentum positronDirection0 = aDynamicPositron->GetMomentumDirection();
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if (verboseLevel>=2) {
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G4cout << " Mom " << positronDirection0 << G4endl;
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G4cout << " Polarization " << positronPolarization << G4endl;
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G4cout << " MaterialPol. " << electronPolarization << G4endl;
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G4cout << " Phys. Volume " << aPVolume->GetName() << G4endl;
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G4cout << " Log. Volume " << aLVolume->GetName() << G4endl;
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G4cout << " Material " << aMaterial << G4endl;
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}
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G4bool isOutRange;
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G4int idx= CurrentMaterialCutsCoupleIndex();
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G4double lAsymmetry = (*theAsymmetryTable)(idx)->
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GetValue(positronEnergy, isOutRange);
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G4double tAsymmetry = (*theTransverseAsymmetryTable)(idx)->
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GetValue(positronEnergy, isOutRange);
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G4double polZZ = positronPolarization.z()*
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electronPolarization*positronDirection0;
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G4double polXX = positronPolarization.x()*
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electronPolarization*G4PolarizationHelper::GetParticleFrameX(positronDirection0);
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G4double polYY = positronPolarization.y()*
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electronPolarization*G4PolarizationHelper::GetParticleFrameY(positronDirection0);
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G4double impact = 1. + polZZ*lAsymmetry + (polXX + polYY)*tAsymmetry;
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mfp *= 1. / impact;
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if (verboseLevel>=2) {
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G4cout << " MeanFreePath: " << mfp / mm << " mm " << G4endl;
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G4cout << " Asymmetry: " << lAsymmetry << ", " << tAsymmetry << G4endl;
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G4cout << " PolProduct: " << polXX << ", " << polYY << ", " << polZZ << G4endl;
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}
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}
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return mfp;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4eplusPolarizedAnnihilation::BuildPhysicsTable(const G4ParticleDefinition& pd)
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{
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G4VEmProcess::BuildPhysicsTable(pd);
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BuildAsymmetryTable(pd);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4eplusPolarizedAnnihilation::PreparePhysicsTable(const G4ParticleDefinition& pd)
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{
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G4VEmProcess::PreparePhysicsTable(pd);
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theAsymmetryTable = G4PhysicsTableHelper::PreparePhysicsTable(theAsymmetryTable);
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theTransverseAsymmetryTable = G4PhysicsTableHelper::PreparePhysicsTable(theTransverseAsymmetryTable);
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}
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void G4eplusPolarizedAnnihilation::BuildAsymmetryTable(const G4ParticleDefinition& part)
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{
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// Access to materials
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const G4ProductionCutsTable* theCoupleTable=
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G4ProductionCutsTable::GetProductionCutsTable();
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size_t numOfCouples = theCoupleTable->GetTableSize();
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G4cout<<" annih-numOfCouples="<<numOfCouples<<"\n";
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for(size_t i=0; i<numOfCouples; ++i) {
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G4cout<<"annih- "<<i<<"/"<<numOfCouples<<"\n";
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if (!theAsymmetryTable) break;
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G4cout<<"annih- "<<theAsymmetryTable->GetFlag(i)<<"\n";
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if (theAsymmetryTable->GetFlag(i)) {
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G4cout<<" building pol-annih ... \n";
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// create physics vector and fill it
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const G4MaterialCutsCouple* couple = theCoupleTable->GetMaterialCutsCouple(i);
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// use same parameters as for lambda
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G4PhysicsVector* aVector = LambdaPhysicsVector(couple);
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G4PhysicsVector* tVector = LambdaPhysicsVector(couple);
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for (G4int j = 0 ; j < LambdaBinning() ; ++j ) {
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G4double lowEdgeEnergy = aVector->GetLowEdgeEnergy(j);
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G4double tasm=0.;
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G4double asym = ComputeAsymmetry(lowEdgeEnergy, couple, part, 0., tasm);
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aVector->PutValue(j,asym);
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tVector->PutValue(j,tasm);
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}
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G4PhysicsTableHelper::SetPhysicsVector(theAsymmetryTable, i, aVector);
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G4PhysicsTableHelper::SetPhysicsVector(theTransverseAsymmetryTable, i, tVector);
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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 G4eplusPolarizedAnnihilation::ComputeAsymmetry(G4double energy,
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const G4MaterialCutsCouple* couple,
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const G4ParticleDefinition& particle,
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G4double cut,
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G4double &tAsymmetry)
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{
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G4double lAsymmetry = 0.0;
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tAsymmetry = 0.0;
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// calculate polarized cross section
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theTargetPolarization=G4ThreeVector(0.,0.,1.);
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emModel->SetTargetPolarization(theTargetPolarization);
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emModel->SetBeamPolarization(theTargetPolarization);
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G4double sigma2=emModel->CrossSection(couple,&particle,energy,cut,energy);
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// calculate transversely polarized cross section
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theTargetPolarization=G4ThreeVector(1.,0.,0.);
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emModel->SetTargetPolarization(theTargetPolarization);
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emModel->SetBeamPolarization(theTargetPolarization);
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G4double sigma3=emModel->CrossSection(couple,&particle,energy,cut,energy);
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// calculate unpolarized cross section
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theTargetPolarization=G4ThreeVector();
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emModel->SetTargetPolarization(theTargetPolarization);
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emModel->SetBeamPolarization(theTargetPolarization);
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G4double sigma0=emModel->CrossSection(couple,&particle,energy,cut,energy);
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// determine assymmetries
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if (sigma0>0.) {
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lAsymmetry=sigma2/sigma0-1.;
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tAsymmetry=sigma3/sigma0-1.;
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}
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return lAsymmetry;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4eplusPolarizedAnnihilation::PrintInfo()
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{
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G4cout << " Polarized model for annihilation into 2 photons"
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<< G4endl;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4VParticleChange* G4eplusPolarizedAnnihilation::AtRestDoIt(const G4Track& aTrack,
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const G4Step& )
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//
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// Performs the e+ e- annihilation when both particles are assumed at rest.
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// It generates two back to back photons with energy = electron_mass.
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// The angular distribution is isotropic.
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// GEANT4 internal units
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//
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// Note : Effects due to binding of atomic electrons are negliged.
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{
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fParticleChange.InitializeForPostStep(aTrack);
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fParticleChange.SetNumberOfSecondaries(2);
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G4double cosTeta = 2.*G4UniformRand()-1. , sinTeta = std::sqrt(1.-cosTeta*cosTeta);
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G4double phi = twopi * G4UniformRand();
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G4ThreeVector direction (sinTeta*std::cos(phi), sinTeta*std::sin(phi), cosTeta);
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fParticleChange.AddSecondary( new G4DynamicParticle (G4Gamma::Gamma(),
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direction, electron_mass_c2) );
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fParticleChange.AddSecondary( new G4DynamicParticle (G4Gamma::Gamma(),
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-direction, electron_mass_c2) );
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// Kill the incident positron
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//
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fParticleChange.ProposeTrackStatus(fStopAndKill);
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return &fParticleChange;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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