Gabriele Cosmo
465 lines
17 KiB
C++
465 lines
17 KiB
C++
//
|
|
// ********************************************************************
|
|
// * 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. *
|
|
// ********************************************************************
|
|
//
|
|
// G4TransportationWithMsc
|
|
//
|
|
// Class Description:
|
|
//
|
|
// It is a generic process of transportation with multiple scattering included
|
|
// in the step limitation and propagation.
|
|
//
|
|
// Original author: Jonas Hahnfeld, 2022
|
|
|
|
// -------------------------------------------------------------------
|
|
//
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
|
|
#include "G4TransportationWithMsc.hh"
|
|
|
|
#include "G4LossTableBuilder.hh"
|
|
#include "G4LossTableManager.hh"
|
|
#include "G4EmConfigurator.hh"
|
|
#include "G4VMscModel.hh"
|
|
|
|
#include "G4DynamicParticle.hh"
|
|
#include "G4Step.hh"
|
|
#include "G4StepPoint.hh"
|
|
#include "G4StepStatus.hh"
|
|
#include "G4Track.hh"
|
|
|
|
#include "G4Electron.hh"
|
|
|
|
#include "G4PhysicalConstants.hh"
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
|
|
static constexpr G4double kLowestKinEnergy = 10 * CLHEP::eV;
|
|
static constexpr G4double kGeomMin = 0.05 * CLHEP::nm;
|
|
static constexpr G4double kMinDisplacement2 = kGeomMin * kGeomMin;
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
|
|
G4TransportationWithMsc::G4TransportationWithMsc(ScatteringType type,
|
|
G4int verbosity)
|
|
: G4Transportation(verbosity, "TransportationWithMsc")
|
|
, fType(type)
|
|
{
|
|
SetVerboseLevel(1);
|
|
|
|
fEmManager = G4LossTableManager::Instance();
|
|
fModelManager = new G4EmModelManager;
|
|
|
|
G4ThreeVector zero;
|
|
fSubStepDynamicParticle =
|
|
new G4DynamicParticle(G4Electron::Definition(), zero);
|
|
fSubStepTrack = new G4Track(fSubStepDynamicParticle, 0, zero);
|
|
fSubStep = new G4Step;
|
|
fSubStepTrack->SetStep(fSubStep);
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
|
|
G4TransportationWithMsc::~G4TransportationWithMsc()
|
|
{
|
|
delete fModelManager;
|
|
// fSubStepDynamicParticle is owned and also deleted by fSubStepTrack!
|
|
delete fSubStepTrack;
|
|
delete fSubStep;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
|
|
void G4TransportationWithMsc::AddMscModel(G4VMscModel* mscModel, G4int order,
|
|
const G4Region* region)
|
|
{
|
|
if(fType != ScatteringType::MultipleScattering)
|
|
{
|
|
G4Exception("G4TransportationWithMsc::AddMscModel", "em0051",
|
|
FatalException,
|
|
"not allowed unless type == MultipleScattering");
|
|
}
|
|
|
|
fModelManager->AddEmModel(order, mscModel, nullptr, region);
|
|
mscModel->SetParticleChange(&fParticleChange);
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
|
|
void G4TransportationWithMsc::PreparePhysicsTable(
|
|
const G4ParticleDefinition& part)
|
|
{
|
|
if(nullptr == fFirstParticle)
|
|
{
|
|
fFirstParticle = ∂
|
|
G4VMultipleScattering* ptr = nullptr;
|
|
auto emConfigurator = fEmManager->EmConfigurator();
|
|
emConfigurator->PrepareModels(&part, ptr, this);
|
|
}
|
|
|
|
if(fFirstParticle == &part)
|
|
{
|
|
G4bool master = fEmManager->IsMaster();
|
|
G4LossTableBuilder* bld = fEmManager->GetTableBuilder();
|
|
G4bool baseMat = bld->GetBaseMaterialFlag();
|
|
const auto* theParameters = G4EmParameters::Instance();
|
|
|
|
if(master)
|
|
{
|
|
SetVerboseLevel(theParameters->Verbose());
|
|
}
|
|
else
|
|
{
|
|
SetVerboseLevel(theParameters->WorkerVerbose());
|
|
}
|
|
|
|
const G4int numberOfModels = fModelManager->NumberOfModels();
|
|
for(G4int i = 0; i < numberOfModels; ++i)
|
|
{
|
|
auto msc = static_cast<G4VMscModel*>(fModelManager->GetModel(i));
|
|
msc->SetMasterThread(master);
|
|
msc->SetPolarAngleLimit(theParameters->MscThetaLimit());
|
|
G4double emax =
|
|
std::min(msc->HighEnergyLimit(), theParameters->MaxKinEnergy());
|
|
msc->SetHighEnergyLimit(emax);
|
|
msc->SetUseBaseMaterials(baseMat);
|
|
}
|
|
|
|
fModelManager->Initialise(fFirstParticle, G4Electron::Electron(),
|
|
verboseLevel);
|
|
}
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
|
|
void G4TransportationWithMsc::BuildPhysicsTable(
|
|
const G4ParticleDefinition& part)
|
|
{
|
|
if(fFirstParticle == &part)
|
|
{
|
|
fEmManager->BuildPhysicsTable(fFirstParticle);
|
|
|
|
if(!fEmManager->IsMaster())
|
|
{
|
|
const auto masterProcess =
|
|
static_cast<const G4TransportationWithMsc*>(GetMasterProcess());
|
|
|
|
// Initialisation of models.
|
|
const G4int numberOfModels = fModelManager->NumberOfModels();
|
|
for(G4int i = 0; i < numberOfModels; ++i)
|
|
{
|
|
auto msc = static_cast<G4VMscModel*>(fModelManager->GetModel(i));
|
|
auto msc0 =
|
|
static_cast<G4VMscModel*>(masterProcess->fModelManager->GetModel(i));
|
|
msc->SetCrossSectionTable(msc0->GetCrossSectionTable(), false);
|
|
msc->InitialiseLocal(fFirstParticle, msc0);
|
|
}
|
|
}
|
|
}
|
|
|
|
if(!G4EmParameters::Instance()->IsPrintLocked() && verboseLevel > 0)
|
|
{
|
|
G4cout << G4endl;
|
|
G4cout << GetProcessName() << ": for " << part.GetParticleName();
|
|
if(fMultipleSteps)
|
|
{
|
|
G4cout << " (multipleSteps: 1)";
|
|
}
|
|
G4cout << G4endl;
|
|
fModelManager->DumpModelList(G4cout, verboseLevel);
|
|
}
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
|
|
void G4TransportationWithMsc::StartTracking(G4Track* track)
|
|
{
|
|
auto* currParticle = track->GetParticleDefinition();
|
|
auto* ionisation = fEmManager->GetEnergyLossProcess(currParticle);
|
|
|
|
fSubStepDynamicParticle->SetDefinition(currParticle);
|
|
|
|
const G4int numberOfModels = fModelManager->NumberOfModels();
|
|
for(G4int i = 0; i < numberOfModels; ++i)
|
|
{
|
|
auto msc = static_cast<G4VMscModel*>(fModelManager->GetModel(i));
|
|
msc->StartTracking(track);
|
|
msc->SetIonisation(ionisation, currParticle);
|
|
}
|
|
|
|
// Ensure that field propagation state is also cleared / prepared
|
|
G4Transportation::StartTracking(track);
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4TransportationWithMsc::AlongStepGetPhysicalInteractionLength(
|
|
const G4Track& track, G4double previousStepSize, G4double currentMinimumStep,
|
|
G4double& proposedSafety, G4GPILSelection* selection)
|
|
{
|
|
*selection = NotCandidateForSelection;
|
|
|
|
const G4double physStepLimit = currentMinimumStep;
|
|
|
|
switch(fType)
|
|
{
|
|
case ScatteringType::MultipleScattering: {
|
|
// Select the MSC model for the current kinetic energy.
|
|
G4VMscModel* mscModel = nullptr;
|
|
const G4double ekin = track.GetKineticEnergy();
|
|
const auto* couple = track.GetMaterialCutsCouple();
|
|
const auto* particleDefinition = track.GetParticleDefinition();
|
|
if(physStepLimit > kGeomMin)
|
|
{
|
|
G4double ekinForSelection = ekin;
|
|
G4double pdgMass = particleDefinition->GetPDGMass();
|
|
if(pdgMass > CLHEP::GeV)
|
|
{
|
|
ekinForSelection *= proton_mass_c2 / pdgMass;
|
|
}
|
|
|
|
if(ekinForSelection >= kLowestKinEnergy)
|
|
{
|
|
mscModel = static_cast<G4VMscModel*>(
|
|
fModelManager->SelectModel(ekinForSelection, couple->GetIndex()));
|
|
if(mscModel == nullptr)
|
|
{
|
|
G4Exception("G4TransportationWithMsc::AlongStepGPIL", "em0052",
|
|
FatalException, "no MSC model found");
|
|
}
|
|
if(!mscModel->IsActive(ekinForSelection))
|
|
{
|
|
mscModel = nullptr;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Call the MSC model to potentially limit the step and convert to
|
|
// geometric path length.
|
|
if(mscModel != nullptr)
|
|
{
|
|
mscModel->SetCurrentCouple(couple);
|
|
|
|
// Use the provided track for the first step.
|
|
const G4Track* currentTrackPtr = &track;
|
|
|
|
G4double currentSafety = proposedSafety;
|
|
G4double currentEnergy = ekin;
|
|
|
|
G4double stepLimitLeft = physStepLimit;
|
|
G4double totalGeometryStepLength = 0, totalTruePathLength = 0;
|
|
G4bool firstStep = true, continueStepping = fMultipleSteps;
|
|
|
|
do
|
|
{
|
|
G4double gPathLength = stepLimitLeft;
|
|
G4double tPathLength =
|
|
mscModel->ComputeTruePathLengthLimit(*currentTrackPtr, gPathLength);
|
|
G4bool mscLimitsStep = (tPathLength < stepLimitLeft);
|
|
if(!fMultipleSteps && mscLimitsStep)
|
|
{
|
|
// MSC limits the step.
|
|
*selection = CandidateForSelection;
|
|
}
|
|
|
|
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;
|
|
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;
|
|
}
|
|
totalGeometryStepLength += geometryStepLength;
|
|
|
|
// Sample MSC direction change and displacement.
|
|
const G4double range =
|
|
mscModel->GetRange(particleDefinition, currentEnergy, couple);
|
|
|
|
tPathLength = mscModel->ComputeTrueStepLength(geometryStepLength);
|
|
|
|
// Protect against wrong t->g->t conversion.
|
|
tPathLength = std::min(tPathLength, stepLimitLeft);
|
|
|
|
totalTruePathLength += tPathLength;
|
|
if(*selection != CandidateForSelection && !mscLimitsStep)
|
|
{
|
|
// If neither MSC nor transportation limits the step, we got the
|
|
// distance we want - make sure we exit the loop.
|
|
continueStepping = false;
|
|
}
|
|
else if(tPathLength >= range)
|
|
{
|
|
// The particle will stop, exit the loop.
|
|
continueStepping = false;
|
|
}
|
|
else
|
|
{
|
|
stepLimitLeft -= tPathLength;
|
|
}
|
|
|
|
// Do not sample scattering at the last or at a small step.
|
|
if(tPathLength < range && tPathLength > kGeomMin)
|
|
{
|
|
static constexpr G4double minSafety = 1.20 * CLHEP::nm;
|
|
static constexpr G4double sFact = 0.99;
|
|
|
|
// The call to SampleScattering() *may* directly fill in the changed
|
|
// direction into fParticleChange, so we have to:
|
|
// 1) Make sure the momentum direction is initialized.
|
|
fParticleChange.ProposeMomentumDirection(fTransportEndMomentumDir);
|
|
// 2) Call SampleScattering(), which *may* change it.
|
|
const G4ThreeVector displacement =
|
|
mscModel->SampleScattering(fTransportEndMomentumDir, minSafety);
|
|
// 3) Get the changed direction and inform G4Transportation.
|
|
fMomentumChanged = true;
|
|
fTransportEndMomentumDir = *fParticleChange.GetMomentumDirection();
|
|
|
|
const G4double r2 = displacement.mag2();
|
|
if(r2 > kMinDisplacement2)
|
|
{
|
|
G4bool positionChanged = true;
|
|
G4double dispR = std::sqrt(r2);
|
|
G4double postSafety = sFact * fpSafetyHelper->ComputeSafety(
|
|
fTransportEndPosition, dispR);
|
|
|
|
// Far away from geometry boundary
|
|
if(postSafety > 0.0 && dispR <= postSafety)
|
|
{
|
|
fTransportEndPosition += displacement;
|
|
|
|
// Near the boundary
|
|
}
|
|
else
|
|
{
|
|
// displaced point is definitely within the volume
|
|
if(dispR < postSafety)
|
|
{
|
|
fTransportEndPosition += displacement;
|
|
|
|
// reduced displacement
|
|
}
|
|
else if(postSafety > kGeomMin)
|
|
{
|
|
fTransportEndPosition += displacement * (postSafety / dispR);
|
|
|
|
// very small postSafety
|
|
}
|
|
else
|
|
{
|
|
positionChanged = false;
|
|
}
|
|
}
|
|
if(positionChanged)
|
|
{
|
|
fpSafetyHelper->ReLocateWithinVolume(fTransportEndPosition);
|
|
}
|
|
}
|
|
}
|
|
|
|
if(continueStepping)
|
|
{
|
|
// Update safety according to the geometry distance.
|
|
if(currentSafety < fEndPointDistance)
|
|
{
|
|
currentSafety = 0;
|
|
}
|
|
else
|
|
{
|
|
currentSafety -= fEndPointDistance;
|
|
}
|
|
|
|
// Update the kinetic energy according to the continuous loss.
|
|
currentEnergy = mscModel->GetEnergy(particleDefinition,
|
|
range - tPathLength, couple);
|
|
|
|
// 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;
|
|
// Also ask for the range again with the initial energy so it is
|
|
// correctly cached in the G4VEnergyLossProcess.
|
|
// FIXME: Asking for a range should never change the cached values!
|
|
(void) mscModel->GetRange(particleDefinition, ekin, couple);
|
|
}
|
|
|
|
fParticleChange.ProposeTrueStepLength(totalTruePathLength);
|
|
|
|
return totalGeometryStepLength;
|
|
}
|
|
}
|
|
}
|
|
|
|
// If we get here, no scattering has happened.
|
|
return G4Transportation::AlongStepGetPhysicalInteractionLength(
|
|
track, previousStepSize, currentMinimumStep, proposedSafety, selection);
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|