Gabriele Cosmo
668 lines
27 KiB
C++
668 lines
27 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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// G4TransportationWithMsc
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//
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// Class Description:
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//
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// It is a generic process of transportation with multiple scattering included
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// in the step limitation and propagation.
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//
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// Original author: Jonas Hahnfeld, 2022
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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 "G4TransportationWithMsc.hh"
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#include "G4DynamicParticle.hh"
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#include "G4Electron.hh"
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#include "G4EmConfigurator.hh"
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#include "G4EmDataHandler.hh"
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#include "G4LossTableBuilder.hh"
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#include "G4LossTableManager.hh"
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#include "G4ParticleChangeForGamma.hh"
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#include "G4ParticleChangeForMSC.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4PhysicsTableHelper.hh"
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#include "G4PhysicsVector.hh"
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#include "G4ProductionCutsTable.hh"
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#include "G4Step.hh"
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#include "G4StepPoint.hh"
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#include "G4StepStatus.hh"
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#include "G4Track.hh"
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#include "G4VMscModel.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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static constexpr G4double kLowestKinEnergy = 10 * CLHEP::eV;
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static constexpr G4double kGeomMin = 0.05 * CLHEP::nm;
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static constexpr G4double kMinDisplacement2 = kGeomMin * kGeomMin;
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4TransportationWithMsc::G4TransportationWithMsc(ScatteringType type, G4int verbosity)
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: G4Transportation(verbosity, "TransportationWithMsc"), fType(type)
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{
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SetVerboseLevel(1);
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fEmManager = G4LossTableManager::Instance();
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fModelManager = new G4EmModelManager;
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if (type == ScatteringType::MultipleScattering) {
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fParticleChangeForMSC = new G4ParticleChangeForMSC;
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}
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else if (type == ScatteringType::SingleScattering) {
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fParticleChangeForSS = new G4ParticleChangeForGamma;
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fSecondariesSS = new std::vector<G4DynamicParticle*>;
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}
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G4ThreeVector zero;
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fSubStepDynamicParticle = new G4DynamicParticle(G4Electron::Definition(), zero);
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fSubStepTrack = new G4Track(fSubStepDynamicParticle, 0, zero);
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fSubStep = new G4Step;
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fSubStepTrack->SetStep(fSubStep);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4TransportationWithMsc::~G4TransportationWithMsc()
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{
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delete fModelManager;
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delete fParticleChangeForMSC;
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delete fEmData;
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delete fParticleChangeForSS;
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delete fSecondariesSS;
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// fSubStepDynamicParticle is owned and also deleted by fSubStepTrack!
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delete fSubStepTrack;
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delete fSubStep;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4TransportationWithMsc::AddMscModel(G4VMscModel* mscModel, G4int order,
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const G4Region* region)
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{
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if (fType != ScatteringType::MultipleScattering) {
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G4Exception("G4TransportationWithMsc::AddMscModel", "em0051", FatalException,
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"not allowed unless type == MultipleScattering");
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}
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fModelManager->AddEmModel(order, mscModel, nullptr, region);
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mscModel->SetParticleChange(fParticleChangeForMSC);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4TransportationWithMsc::AddSSModel(G4VEmModel* model, G4int order, const G4Region* region)
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{
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if (fType != ScatteringType::SingleScattering) {
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G4Exception("G4TransportationWithMsc::AddSSModel", "em0051", FatalException,
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"not allowed unless type == SingleScattering");
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}
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fModelManager->AddEmModel(order, model, nullptr, region);
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model->SetPolarAngleLimit(0.0);
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model->SetParticleChange(fParticleChangeForSS);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4TransportationWithMsc::PreparePhysicsTable(const G4ParticleDefinition& part)
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{
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if (nullptr == fFirstParticle) {
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fFirstParticle = ∂
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G4VMultipleScattering* ptr = nullptr;
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auto emConfigurator = fEmManager->EmConfigurator();
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emConfigurator->PrepareModels(&part, ptr, this);
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}
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if (fFirstParticle == &part) {
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G4bool master = fEmManager->IsMaster();
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G4LossTableBuilder* bld = fEmManager->GetTableBuilder();
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G4bool baseMat = bld->GetBaseMaterialFlag();
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const auto* theParameters = G4EmParameters::Instance();
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if (master) {
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SetVerboseLevel(theParameters->Verbose());
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}
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else {
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SetVerboseLevel(theParameters->WorkerVerbose());
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}
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const G4int numberOfModels = fModelManager->NumberOfModels();
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if (fType == ScatteringType::MultipleScattering) {
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for (G4int i = 0; i < numberOfModels; ++i) {
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auto msc = static_cast<G4VMscModel*>(fModelManager->GetModel(i));
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msc->SetPolarAngleLimit(theParameters->MscThetaLimit());
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G4double emax = std::min(msc->HighEnergyLimit(), theParameters->MaxKinEnergy());
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msc->SetHighEnergyLimit(emax);
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msc->SetUseBaseMaterials(baseMat);
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}
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}
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else if (fType == ScatteringType::SingleScattering) {
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if (master) {
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if (fEmData == nullptr) {
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fEmData = new G4EmDataHandler(2);
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}
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fLambdaTable = fEmData->MakeTable(0);
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bld->InitialiseBaseMaterials(fLambdaTable);
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}
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}
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fCuts = fModelManager->Initialise(fFirstParticle, G4Electron::Electron(), verboseLevel);
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4TransportationWithMsc::BuildPhysicsTable(const G4ParticleDefinition& part)
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{
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if (fFirstParticle == &part) {
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fEmManager->BuildPhysicsTable(fFirstParticle);
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if (fEmManager->IsMaster()) {
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if (fType == ScatteringType::SingleScattering) {
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const auto* theParameters = G4EmParameters::Instance();
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G4LossTableBuilder* bld = fEmManager->GetTableBuilder();
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const G4ProductionCutsTable* theCoupleTable =
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G4ProductionCutsTable::GetProductionCutsTable();
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std::size_t numOfCouples = theCoupleTable->GetTableSize();
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G4double emin = theParameters->MinKinEnergy();
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G4double emax = theParameters->MaxKinEnergy();
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G4double scale = emax / emin;
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G4int nbin = theParameters->NumberOfBinsPerDecade() * G4lrint(std::log10(scale));
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scale = nbin / G4Log(scale);
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G4int bin = G4lrint(scale * G4Log(emax / emin));
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bin = std::max(bin, 5);
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for (std::size_t i = 0; i < numOfCouples; ++i) {
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if (!bld->GetFlag(i)) continue;
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// Create physics vector and fill it
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const G4MaterialCutsCouple* couple = theCoupleTable->GetMaterialCutsCouple((G4int)i);
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auto* aVector = new G4PhysicsLogVector(emin, emax, bin, /*splineFlag*/ true);
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fModelManager->FillLambdaVector(aVector, couple, /*startNull*/ false);
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aVector->FillSecondDerivatives();
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G4PhysicsTableHelper::SetPhysicsVector(fLambdaTable, i, aVector);
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}
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}
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}
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else {
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const auto masterProcess = static_cast<const G4TransportationWithMsc*>(GetMasterProcess());
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// Initialisation of models.
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const G4int numberOfModels = fModelManager->NumberOfModels();
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if (fType == ScatteringType::MultipleScattering) {
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for (G4int i = 0; i < numberOfModels; ++i) {
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auto msc = static_cast<G4VMscModel*>(fModelManager->GetModel(i));
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auto msc0 = static_cast<G4VMscModel*>(masterProcess->fModelManager->GetModel(i));
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msc->SetCrossSectionTable(msc0->GetCrossSectionTable(), false);
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msc->InitialiseLocal(fFirstParticle, msc0);
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}
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}
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else if (fType == ScatteringType::SingleScattering) {
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this->fLambdaTable = masterProcess->fLambdaTable;
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}
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}
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}
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if (!G4EmParameters::Instance()->IsPrintLocked() && verboseLevel > 0) {
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G4cout << G4endl;
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G4cout << GetProcessName() << ": for " << part.GetParticleName();
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if (fMultipleSteps) {
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G4cout << " (multipleSteps: 1)";
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}
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G4cout << G4endl;
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fModelManager->DumpModelList(G4cout, verboseLevel);
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4TransportationWithMsc::StartTracking(G4Track* track)
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{
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auto* currParticle = track->GetParticleDefinition();
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fIonisation = fEmManager->GetEnergyLossProcess(currParticle);
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fSubStepDynamicParticle->SetDefinition(currParticle);
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const G4int numberOfModels = fModelManager->NumberOfModels();
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if (fType == ScatteringType::MultipleScattering) {
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for (G4int i = 0; i < numberOfModels; ++i) {
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auto msc = static_cast<G4VMscModel*>(fModelManager->GetModel(i));
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msc->StartTracking(track);
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msc->SetIonisation(fIonisation, currParticle);
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}
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}
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// Ensure that field propagation state is also cleared / prepared
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G4Transportation::StartTracking(track);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4TransportationWithMsc::AlongStepGetPhysicalInteractionLength(const G4Track& track,
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G4double previousStepSize,
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G4double currentMinimumStep,
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G4double& proposedSafety,
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G4GPILSelection* selection)
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{
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*selection = NotCandidateForSelection;
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const G4double physStepLimit = currentMinimumStep;
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switch (fType) {
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case ScatteringType::MultipleScattering: {
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// Select the MSC model for the current kinetic energy.
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G4VMscModel* mscModel = nullptr;
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const G4double ekin = track.GetKineticEnergy();
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const auto* couple = track.GetMaterialCutsCouple();
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const auto* particleDefinition = track.GetParticleDefinition();
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if (physStepLimit > kGeomMin) {
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G4double ekinForSelection = ekin;
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G4double pdgMass = particleDefinition->GetPDGMass();
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if (pdgMass > CLHEP::GeV) {
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ekinForSelection *= proton_mass_c2 / pdgMass;
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}
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if (ekinForSelection >= kLowestKinEnergy) {
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mscModel = static_cast<G4VMscModel*>(
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fModelManager->SelectModel(ekinForSelection, couple->GetIndex()));
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if (mscModel == nullptr) {
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G4Exception("G4TransportationWithMsc::AlongStepGPIL", "em0052", FatalException,
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"no MSC model found");
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}
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if (!mscModel->IsActive(ekinForSelection)) {
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mscModel = nullptr;
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}
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}
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}
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// Call the MSC model to potentially limit the step and convert to
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// geometric path length.
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if (mscModel != nullptr) {
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mscModel->SetCurrentCouple(couple);
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// Use the provided track for the first step.
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const G4Track* currentTrackPtr = &track;
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G4double currentSafety = proposedSafety;
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G4double currentEnergy = ekin;
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G4double stepLimitLeft = physStepLimit;
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G4double totalGeometryStepLength = 0, totalTruePathLength = 0;
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G4bool firstStep = true, continueStepping = fMultipleSteps;
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do {
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G4double gPathLength = stepLimitLeft;
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G4double tPathLength =
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mscModel->ComputeTruePathLengthLimit(*currentTrackPtr, gPathLength);
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G4bool mscLimitsStep = (tPathLength < stepLimitLeft);
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if (!fMultipleSteps && mscLimitsStep) {
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// MSC limits the step.
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*selection = CandidateForSelection;
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}
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if (!firstStep) {
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// Move the navigator to where the previous step ended.
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fLinearNavigator->LocateGlobalPointWithinVolume(fTransportEndPosition);
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}
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G4GPILSelection transportSelection;
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G4double geometryStepLength = G4Transportation::AlongStepGetPhysicalInteractionLength(
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*currentTrackPtr, previousStepSize, gPathLength, currentSafety, &transportSelection);
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if (geometryStepLength < gPathLength) {
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// Transportation limits the step, ie the track hit a boundary.
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*selection = CandidateForSelection;
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continueStepping = false;
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}
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if (fTransportEndKineticEnergy != currentEnergy) {
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// Field propagation changed the energy, it's not possible to
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// estimate the continuous energy loss and continue stepping.
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continueStepping = false;
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}
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if (firstStep) {
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proposedSafety = currentSafety;
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}
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totalGeometryStepLength += geometryStepLength;
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// Sample MSC direction change and displacement.
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const G4double range = mscModel->GetRange(particleDefinition, currentEnergy, couple);
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tPathLength = mscModel->ComputeTrueStepLength(geometryStepLength);
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// Protect against wrong t->g->t conversion.
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tPathLength = std::min(tPathLength, stepLimitLeft);
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totalTruePathLength += tPathLength;
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if (*selection != CandidateForSelection && !mscLimitsStep) {
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// If neither MSC nor transportation limits the step, we got the
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// distance we want - make sure we exit the loop.
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continueStepping = false;
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}
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else if (tPathLength >= range) {
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// The particle will stop, exit the loop.
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continueStepping = false;
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}
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else {
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stepLimitLeft -= tPathLength;
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}
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// Do not sample scattering at the last or at a small step.
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if (tPathLength < range && tPathLength > kGeomMin) {
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static constexpr G4double minSafety = 1.20 * CLHEP::nm;
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static constexpr G4double sFact = 0.99;
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// The call to SampleScattering() *may* directly fill in the changed
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// direction into fParticleChangeForMSC, so we have to:
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// 1) Make sure the momentum direction is initialized.
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fParticleChangeForMSC->ProposeMomentumDirection(fTransportEndMomentumDir);
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// 2) Call SampleScattering(), which *may* change it.
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const G4ThreeVector displacement =
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mscModel->SampleScattering(fTransportEndMomentumDir, minSafety);
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// 3) Get the changed direction.
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fTransportEndMomentumDir = *fParticleChangeForMSC->GetProposedMomentumDirection();
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const G4double r2 = displacement.mag2();
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if (r2 > kMinDisplacement2) {
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G4bool positionChanged = true;
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G4double dispR = std::sqrt(r2);
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G4double postSafety =
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sFact * fpSafetyHelper->ComputeSafety(fTransportEndPosition, dispR);
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// Far away from geometry boundary
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if (postSafety > 0.0 && dispR <= postSafety) {
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fTransportEndPosition += displacement;
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// Near the boundary
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}
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else {
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// displaced point is definitely within the volume
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if (dispR < postSafety) {
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fTransportEndPosition += displacement;
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// reduced displacement
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}
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else if (postSafety > kGeomMin) {
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fTransportEndPosition += displacement * (postSafety / dispR);
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// very small postSafety
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}
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else {
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positionChanged = false;
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}
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}
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if (positionChanged) {
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fpSafetyHelper->ReLocateWithinVolume(fTransportEndPosition);
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}
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}
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}
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if (continueStepping) {
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// Update safety according to the geometry distance.
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if (currentSafety < fEndPointDistance) {
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currentSafety = 0;
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}
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else {
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currentSafety -= fEndPointDistance;
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}
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// Update the kinetic energy according to the continuous loss.
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currentEnergy = mscModel->GetEnergy(particleDefinition, range - tPathLength, couple);
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// From now on, use the track that we can update below.
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currentTrackPtr = fSubStepTrack;
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fSubStepDynamicParticle->SetKineticEnergy(currentEnergy);
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fSubStepDynamicParticle->SetMomentumDirection(fTransportEndMomentumDir);
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fSubStepTrack->SetPosition(fTransportEndPosition);
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G4StepPoint& subPreStepPoint = *fSubStep->GetPreStepPoint();
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subPreStepPoint.SetMaterialCutsCouple(couple);
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subPreStepPoint.SetPosition(fTransportEndPosition);
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subPreStepPoint.SetSafety(currentSafety);
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subPreStepPoint.SetStepStatus(fAlongStepDoItProc);
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}
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firstStep = false;
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} while (continueStepping);
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// Note: currentEnergy is only updated if continueStepping is true.
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// In case field propagation changed the energy, this flag is
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// immediately set to false and currentEnergy is still equal to the
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// initial kinetic energy stored in ekin.
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if (currentEnergy != ekin) {
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// If field propagation didn't change the energy and we potentially
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// did multiple steps, reset the energy that G4Transportation will
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// propose to not subtract the energy loss twice.
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fTransportEndKineticEnergy = ekin;
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// Also ask for the range again with the initial energy so it is
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// correctly cached in the G4VEnergyLossProcess.
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// FIXME: Asking for a range should never change the cached values!
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(void)mscModel->GetRange(particleDefinition, ekin, couple);
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}
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fParticleChange.ProposeTrueStepLength(totalTruePathLength);
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// Inform G4Transportation that the momentum might have changed due
|
|
// to scattering. We do this unconditionally to avoid the situation
|
|
// where the last step is done without MSC and G4Transportation reset
|
|
// the flag, for example when running without field.
|
|
fMomentumChanged = true;
|
|
|
|
return totalGeometryStepLength;
|
|
}
|
|
break;
|
|
}
|
|
|
|
case ScatteringType::SingleScattering: {
|
|
// Select the model for the current kinetic energy.
|
|
const G4double ekin = track.GetKineticEnergy();
|
|
const auto* couple = track.GetMaterialCutsCouple();
|
|
const auto* particleDefinition = track.GetParticleDefinition();
|
|
|
|
G4double ekinForSelection = ekin;
|
|
G4double pdgMass = particleDefinition->GetPDGMass();
|
|
if (pdgMass > CLHEP::GeV) {
|
|
ekinForSelection *= proton_mass_c2 / pdgMass;
|
|
}
|
|
|
|
G4VEmModel* currentModel = fModelManager->SelectModel(ekinForSelection, couple->GetIndex());
|
|
if (currentModel == nullptr) {
|
|
G4Exception("G4TransportationWithMsc::AlongStepGPIL", "em0052", FatalException,
|
|
"no scattering model found");
|
|
}
|
|
if (!currentModel->IsActive(ekinForSelection)) {
|
|
currentModel = nullptr;
|
|
}
|
|
|
|
if (currentModel != nullptr) {
|
|
currentModel->SetCurrentCouple(couple);
|
|
G4int coupleIndex = couple->GetIndex();
|
|
|
|
// Compute mean free path.
|
|
G4double logEkin = track.GetDynamicParticle()->GetLogKineticEnergy();
|
|
G4double lambda = ((*fLambdaTable)[coupleIndex])->LogVectorValue(ekin, logEkin);
|
|
if (lambda > 0.0) {
|
|
// Assume that the mean free path and dE/dx are constant along the
|
|
// step, which is a valid approximation for most cases.
|
|
G4double meanFreePath = 1.0 / lambda;
|
|
G4double dedx = fIonisation->GetDEDX(ekin, couple);
|
|
|
|
G4double currentSafety = proposedSafety;
|
|
G4double currentEnergy = ekin;
|
|
|
|
// Use the provided track for the first step.
|
|
const G4Track* currentTrackPtr = &track;
|
|
|
|
G4double stepLimitLeft = physStepLimit;
|
|
G4double totalStepLength = 0;
|
|
G4bool firstStep = true, continueStepping = fMultipleSteps;
|
|
|
|
do {
|
|
G4double interactionLength = meanFreePath * -G4Log(G4UniformRand());
|
|
|
|
G4bool ssLimitsStep = (interactionLength < stepLimitLeft);
|
|
G4double gPathLength = stepLimitLeft;
|
|
if (ssLimitsStep) {
|
|
if (!fMultipleSteps) {
|
|
// Scattering limits the step.
|
|
*selection = CandidateForSelection;
|
|
}
|
|
gPathLength = interactionLength;
|
|
}
|
|
|
|
if (!firstStep) {
|
|
// Move the navigator to where the previous step ended.
|
|
fLinearNavigator->LocateGlobalPointWithinVolume(fTransportEndPosition);
|
|
}
|
|
|
|
G4GPILSelection transportSelection;
|
|
G4double geometryStepLength = G4Transportation::AlongStepGetPhysicalInteractionLength(
|
|
*currentTrackPtr, previousStepSize, gPathLength, currentSafety, &transportSelection);
|
|
if (geometryStepLength < gPathLength) {
|
|
// Transportation limits the step, ie the track hit a boundary.
|
|
*selection = CandidateForSelection;
|
|
ssLimitsStep = false;
|
|
continueStepping = false;
|
|
}
|
|
if (fTransportEndKineticEnergy != currentEnergy) {
|
|
// Field propagation changed the energy, it's not possible to
|
|
// estimate the continuous energy loss and continue stepping.
|
|
continueStepping = false;
|
|
}
|
|
|
|
if (firstStep) {
|
|
proposedSafety = currentSafety;
|
|
}
|
|
totalStepLength += geometryStepLength;
|
|
|
|
if (*selection != CandidateForSelection && !ssLimitsStep) {
|
|
// If neither scattering nor transportation limits the step, we
|
|
// got the distance we want - make sure we exit the loop.
|
|
continueStepping = false;
|
|
}
|
|
else {
|
|
stepLimitLeft -= geometryStepLength;
|
|
}
|
|
|
|
// Update the kinetic energy according to the continuous loss.
|
|
G4double energyAfterLinearLoss =
|
|
fTransportEndKineticEnergy - geometryStepLength * dedx;
|
|
|
|
if (ssLimitsStep) {
|
|
fSubStepDynamicParticle->SetKineticEnergy(energyAfterLinearLoss);
|
|
|
|
// The call to SampleSecondaries() directly fills in the changed
|
|
// direction into fParticleChangeForSS, so we have to:
|
|
// 1) Set the momentum direction in dynamic particle.
|
|
fSubStepDynamicParticle->SetMomentumDirection(fTransportEndMomentumDir);
|
|
// 2) Call SampleSecondaries(), which changes the direction.
|
|
currentModel->SampleSecondaries(fSecondariesSS, couple, fSubStepDynamicParticle,
|
|
(*fCuts)[coupleIndex]);
|
|
// 3) Get the changed direction.
|
|
fTransportEndMomentumDir = fParticleChangeForSS->GetProposedMomentumDirection();
|
|
|
|
// Check that the model neither created secondaries nor proposed
|
|
// a local energy deposit because this process does not know how
|
|
// to handle these cases.
|
|
if (fSecondariesSS->size() > 0) {
|
|
G4Exception("G4TransportationWithMsc::AlongStepGPIL", "em0053", FatalException,
|
|
"scattering model created secondaries");
|
|
}
|
|
if (fParticleChangeForSS->GetLocalEnergyDeposit() > 0) {
|
|
G4Exception("G4TransportationWithMsc::AlongStepGPIL", "em0053", FatalException,
|
|
"scattering model proposed energy deposit");
|
|
}
|
|
}
|
|
|
|
if (continueStepping) {
|
|
// Update safety according to the geometry distance.
|
|
if (currentSafety < fEndPointDistance) {
|
|
currentSafety = 0;
|
|
}
|
|
else {
|
|
currentSafety -= fEndPointDistance;
|
|
}
|
|
|
|
// Update the energy taking continuous loss into account.
|
|
currentEnergy = energyAfterLinearLoss;
|
|
|
|
// From now on, use the track that we can update below.
|
|
currentTrackPtr = fSubStepTrack;
|
|
|
|
fSubStepDynamicParticle->SetKineticEnergy(currentEnergy);
|
|
fSubStepDynamicParticle->SetMomentumDirection(fTransportEndMomentumDir);
|
|
fSubStepTrack->SetPosition(fTransportEndPosition);
|
|
|
|
G4StepPoint& subPreStepPoint = *fSubStep->GetPreStepPoint();
|
|
subPreStepPoint.SetMaterialCutsCouple(couple);
|
|
subPreStepPoint.SetPosition(fTransportEndPosition);
|
|
subPreStepPoint.SetSafety(currentSafety);
|
|
subPreStepPoint.SetStepStatus(fAlongStepDoItProc);
|
|
}
|
|
firstStep = false;
|
|
} while (continueStepping);
|
|
|
|
// Note: currentEnergy is only updated if continueStepping is true.
|
|
// In case field propagation changed the energy, this flag is
|
|
// immediately set to false and currentEnergy is still equal to the
|
|
// initial kinetic energy stored in ekin.
|
|
if (currentEnergy != ekin) {
|
|
// If field propagation didn't change the energy and we potentially
|
|
// did multiple steps, reset the energy that G4Transportation will
|
|
// propose to not subtract the energy loss twice.
|
|
fTransportEndKineticEnergy = ekin;
|
|
}
|
|
|
|
fParticleChange.ProposeTrueStepLength(totalStepLength);
|
|
|
|
// Inform G4Transportation that the momentum might have changed due
|
|
// to scattering, even if there is no field.
|
|
fMomentumChanged = true;
|
|
|
|
return totalStepLength;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If we get here, no scattering has happened.
|
|
return G4Transportation::AlongStepGetPhysicalInteractionLength(
|
|
track, previousStepSize, currentMinimumStep, proposedSafety, selection);
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|