Gabriele Cosmo
527 lines
18 KiB
C++
527 lines
18 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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//
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//
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//
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// --------------------------------------------------------------
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// GEANT 4 class implementation file
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//
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// History: first implementation, based on object model of
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// 2nd December 1995, G.Cosmo
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// 7 July 1996 H.Kurashige
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// ------------------------------------------------------------
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// remove BuildPhysicsTable() 28 Nov. 1997 H.Kurashige
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// change DBL_EPSIRON to DBL_MIN 14 Dec. 1997 H.Kurashige
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// modified for new ParticleChange 12 Mar. 1998 H.Kurashige
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// modified for "GoodForTrackingFlag" 19 June 1998 H.Kurashige
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// rename thePhysicsTable to aPhyscisTable 2 Aug. 1998 H.Kurashige
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// modified IsApplicable in order to protect the decay from registered
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// to resonances 12 Dec. 1998 H.Kurashige
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// remove G4ParticleMomentum 6 Feb. 99 H.Kurashige
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// modified IsApplicable to activate G4Decay for resonances 1 Mar. 00 H.Kurashige
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// Add External Decayer 23 Feb. 2001 H.Kurashige
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// change LowestBinValue,HighestBinValue and TotBin(200) 9 Feb. 2002
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//
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#include "G4Decay.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4SystemOfUnits.hh"
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#include "G4DynamicParticle.hh"
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#include "G4DecayProducts.hh"
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#include "G4DecayTable.hh"
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#include "G4VDecayChannel.hh"
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#include "G4PhysicsLogVector.hh"
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#include "G4ParticleChangeForDecay.hh"
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#include "G4VExtDecayer.hh"
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// constructor
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G4Decay::G4Decay(const G4String& processName)
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:G4VRestDiscreteProcess(processName, fDecay),
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verboseLevel(1),
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HighestValue(20.0),
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fRemainderLifeTime(-1.0),
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pExtDecayer(nullptr)
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{
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// set Process Sub Type
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SetProcessSubType(static_cast<int>(DECAY));
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << "G4Decay constructor " << " Name:" << processName << G4endl;
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}
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#endif
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pParticleChange = &fParticleChangeForDecay;
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}
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G4Decay::~G4Decay()
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{
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if (pExtDecayer != nullptr) {
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delete pExtDecayer;
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}
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}
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G4bool G4Decay::IsApplicable(const G4ParticleDefinition& aParticleType)
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{
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// check if the particle is stable?
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if (aParticleType.GetPDGLifeTime() <0.0) {
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return false;
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} else if (aParticleType.GetPDGMass() <= 0.0*MeV) {
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return false;
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} else {
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return true;
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}
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}
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G4double G4Decay::GetMeanLifeTime(const G4Track& aTrack ,
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G4ForceCondition*)
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{
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// returns the mean free path in GEANT4 internal units
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G4double meanlife;
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// get particle
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const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle();
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const G4ParticleDefinition* aParticleDef = aParticle->GetDefinition();
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G4double aLife = aParticleDef->GetPDGLifeTime();
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// check if the particle is stable?
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if (aParticleDef->GetPDGStable()) {
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//1000000 times the life time of the universe
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meanlife = 1e24 * s;
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} else {
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meanlife = aLife;
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}
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << "mean life time: "<< meanlife/ns << "[ns]" << G4endl;
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}
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#endif
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return meanlife;
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}
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G4double G4Decay::GetMeanFreePath(const G4Track& aTrack,G4double, G4ForceCondition*)
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{
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// get particle
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const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle();
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const G4ParticleDefinition* aParticleDef = aParticle->GetDefinition();
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G4double aMass = aParticle->GetMass();
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G4double aLife = aParticleDef->GetPDGLifeTime();
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// returns the mean free path in GEANT4 internal units
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G4double pathlength;
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G4double aCtau = c_light * aLife;
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// check if the particle is stable?
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if (aParticleDef->GetPDGStable()) {
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pathlength = DBL_MAX;
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//check if the particle has very short life time ?
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} else if (aCtau < DBL_MIN) {
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pathlength = DBL_MIN;
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} else {
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//calculate the mean free path
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// by using normalized kinetic energy (= Ekin/mass)
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G4double rKineticEnergy = aParticle->GetKineticEnergy()/aMass;
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if ( rKineticEnergy > HighestValue) {
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// gamma >> 1
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pathlength = ( rKineticEnergy + 1.0)* aCtau;
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} else if ( rKineticEnergy < DBL_MIN ) {
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// too slow particle
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << "G4Decay::GetMeanFreePath() !!particle stops!!";
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G4cout << aParticleDef->GetParticleName() << G4endl;
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G4cout << "KineticEnergy:" << aParticle->GetKineticEnergy()/GeV <<"[GeV]";
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}
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#endif
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pathlength = DBL_MIN;
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} else {
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// beta <1
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pathlength = (aParticle->GetTotalMomentum())/aMass*aCtau ;
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}
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}
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return pathlength;
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}
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void G4Decay::BuildPhysicsTable(const G4ParticleDefinition&)
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{
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return;
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}
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G4VParticleChange* G4Decay::DecayIt(const G4Track& aTrack, const G4Step& )
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{
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// The DecayIt() method returns by pointer a particle-change object.
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// Units are expressed in GEANT4 internal units.
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// Initialize ParticleChange
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// all members of G4VParticleChange are set to equal to
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// corresponding member in G4Track
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fParticleChangeForDecay.Initialize(aTrack);
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// get particle
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const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle();
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const G4ParticleDefinition* aParticleDef = aParticle->GetDefinition();
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// check if the particle is stable
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if (aParticleDef->GetPDGStable()) return &fParticleChangeForDecay ;
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//check if thePreAssignedDecayProducts exists
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const G4DecayProducts* o_products = (aParticle->GetPreAssignedDecayProducts());
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G4bool isPreAssigned = (o_products != nullptr);
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G4DecayProducts* products = nullptr;
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// decay table
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G4DecayTable *decaytable = aParticleDef->GetDecayTable();
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// check if external decayer exists
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G4bool isExtDecayer = (decaytable == nullptr) && (pExtDecayer != nullptr);
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// Error due to NO Decay Table
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if ( (decaytable == nullptr) && !isExtDecayer && !isPreAssigned ){
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if (GetVerboseLevel()>0) {
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G4cout << "G4Decay::DoIt : decay table not defined for ";
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G4cout << aParticle->GetDefinition()->GetParticleName()<< G4endl;
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}
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G4ExceptionDescription ed;
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ed << "For " << aParticle->GetDefinition()->GetParticleName()
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<< " decay probability exist but decay table is not defined "
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<< "- the particle will be killed;\n"
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<< " isExtDecayer: " << isExtDecayer
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<< "; isPreAssigned: " << isPreAssigned;
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G4Exception( "G4Decay::DecayIt ",
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"DECAY101",JustWarning, ed);
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fParticleChangeForDecay.SetNumberOfSecondaries(0);
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// Kill the parent particle
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fParticleChangeForDecay.ProposeTrackStatus( fStopAndKill ) ;
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fParticleChangeForDecay.ProposeLocalEnergyDeposit(0.0);
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ClearNumberOfInteractionLengthLeft();
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return &fParticleChangeForDecay ;
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}
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if (isPreAssigned) {
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// copy decay products
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products = new G4DecayProducts(*o_products);
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} else if ( isExtDecayer ) {
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// decay according to external decayer
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products = pExtDecayer->ImportDecayProducts(aTrack);
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} else {
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// Decay according to decay table.
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// Keep trying to choose a candidate decay channel if the dynamic mass
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// of the decaying particle is below the sum of the PDG masses of the
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// candidate daughter particles.
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// This is needed because the decay table used in Geant4 is based on
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// the assumption of nominal PDG masses, but a wide resonance can have
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// a dynamic masses well below its nominal PDG masses, and therefore
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// some of its decay channels can be below the kinematical threshold.
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// Note that, for simplicity, we ignore here the possibility that
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// one or more of the candidate daughter particles can be, in turn,
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// wide resonance. However, if this is the case, and the channel is
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// accepted, then the masses of the resonance daughter particles will
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// be sampled by taking into account their widths.
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G4VDecayChannel* decaychannel = nullptr;
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G4double massParent = aParticle->GetMass();
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decaychannel = decaytable->SelectADecayChannel(massParent);
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if ( decaychannel == nullptr) {
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// decay channel not found
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G4ExceptionDescription ed;
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ed << "Can not determine decay channel for "
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<< aParticleDef->GetParticleName() << G4endl
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<< " mass of dynamic particle: "
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<< massParent/GeV << " (GEV)" << G4endl
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<< " dacay table has " << decaytable->entries()
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<< " entries" << G4endl;
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G4double checkedmass=massParent;
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if (massParent < 0.) {
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checkedmass=aParticleDef->GetPDGMass();
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ed << "Using PDG mass ("<<checkedmass/GeV
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<< "(GeV)) in IsOKWithParentMass" << G4endl;
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}
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for (G4int ic =0;ic <decaytable->entries();++ic) {
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G4VDecayChannel * dc= decaytable->GetDecayChannel(ic);
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ed << ic << ": BR " << dc->GetBR() << ", IsOK? "
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<< dc->IsOKWithParentMass(checkedmass)
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<< ", --> ";
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G4int ndaughters=dc->GetNumberOfDaughters();
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for (G4int id=0;id<ndaughters;++id) {
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if (id>0) ed << " + "; // seperator, except for first
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ed << dc->GetDaughterName(id);
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}
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ed << G4endl;
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}
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G4Exception("G4Decay::DoIt", "DECAY003", FatalException,ed);
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} else {
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// execute DecayIt()
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#ifdef G4VERBOSE
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G4int temp = decaychannel->GetVerboseLevel();
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if (GetVerboseLevel()>1) {
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G4cout << "G4Decay::DoIt : selected decay channel addr:"
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<< decaychannel <<G4endl;
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decaychannel->SetVerboseLevel(GetVerboseLevel());
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}
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#endif
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products = decaychannel->DecayIt(aParticle->GetMass());
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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decaychannel->SetVerboseLevel(temp);
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}
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#endif
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>2) {
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if (! products->IsChecked() ) products->DumpInfo();
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}
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#endif
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}
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}
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// get parent particle information ...................................
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G4double ParentEnergy = aParticle->GetTotalEnergy();
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G4double ParentMass = aParticle->GetMass();
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if (ParentEnergy < ParentMass) {
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G4ExceptionDescription ed;
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ed << "Total Energy is less than its mass - increased the energy"
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<< "\n Particle: " << aParticle->GetDefinition()->GetParticleName()
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<< "\n Energy:" << ParentEnergy/MeV << "[MeV]"
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<< "\n Mass:" << ParentMass/MeV << "[MeV]";
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G4Exception( "G4Decay::DecayIt ",
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"DECAY102",JustWarning, ed);
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ParentEnergy = ParentMass;
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}
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G4ThreeVector ParentDirection(aParticle->GetMomentumDirection());
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//boost all decay products to laboratory frame
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G4double energyDeposit = 0.0;
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G4double finalGlobalTime = aTrack.GetGlobalTime();
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G4double finalLocalTime = aTrack.GetLocalTime();
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if (aTrack.GetTrackStatus() == fStopButAlive ){
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// AtRest case
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finalGlobalTime += fRemainderLifeTime;
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finalLocalTime += fRemainderLifeTime;
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energyDeposit += aParticle->GetKineticEnergy();
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if (isPreAssigned) products->Boost( ParentEnergy, ParentDirection);
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} else {
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// PostStep case
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if (!isExtDecayer) products->Boost( ParentEnergy, ParentDirection);
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}
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// set polarization for daughter particles
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DaughterPolarization(aTrack, products);
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//add products in fParticleChangeForDecay
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G4int numberOfSecondaries = products->entries();
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fParticleChangeForDecay.SetNumberOfSecondaries(numberOfSecondaries);
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << "G4Decay::DoIt : Decay vertex :";
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G4cout << " Time: " << finalGlobalTime/ns << "[ns]";
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G4cout << " X:" << (aTrack.GetPosition()).x() /cm << "[cm]";
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G4cout << " Y:" << (aTrack.GetPosition()).y() /cm << "[cm]";
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G4cout << " Z:" << (aTrack.GetPosition()).z() /cm << "[cm]";
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G4cout << G4endl;
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G4cout << "G4Decay::DoIt : decay products in Lab. Frame" << G4endl;
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products->DumpInfo();
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}
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#endif
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G4int index;
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G4ThreeVector currentPosition;
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const G4TouchableHandle thand = aTrack.GetTouchableHandle();
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for (index=0; index < numberOfSecondaries; index++){
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// get current position of the track
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currentPosition = aTrack.GetPosition();
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// create a new track object
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G4Track* secondary = new G4Track( products->PopProducts(),
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finalGlobalTime ,
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currentPosition );
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// switch on good for tracking flag
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secondary->SetGoodForTrackingFlag();
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secondary->SetTouchableHandle(thand);
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// add the secondary track in the List
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fParticleChangeForDecay.AddSecondary(secondary);
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}
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delete products;
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// Kill the parent particle
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fParticleChangeForDecay.ProposeTrackStatus( fStopAndKill ) ;
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fParticleChangeForDecay.ProposeLocalEnergyDeposit(energyDeposit);
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fParticleChangeForDecay.ProposeLocalTime( finalLocalTime );
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// Clear NumberOfInteractionLengthLeft
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ClearNumberOfInteractionLengthLeft();
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return &fParticleChangeForDecay ;
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}
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void G4Decay::DaughterPolarization(const G4Track& , G4DecayProducts* )
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{
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// empty implementation
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}
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void G4Decay::StartTracking(G4Track*)
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{
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currentInteractionLength = -1.0;
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ResetNumberOfInteractionLengthLeft();
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fRemainderLifeTime = -1.0;
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}
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void G4Decay::EndTracking()
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{
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// Clear NumberOfInteractionLengthLeft
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ClearNumberOfInteractionLengthLeft();
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currentInteractionLength = -1.0;
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}
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G4double G4Decay::PostStepGetPhysicalInteractionLength(
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const G4Track& track,
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G4double previousStepSize,
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G4ForceCondition* condition
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)
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{
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// condition is set to "Not Forced"
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*condition = NotForced;
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// pre-assigned Decay time
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G4double pTime = track.GetDynamicParticle()->GetPreAssignedDecayProperTime();
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G4double aLife = track.GetDynamicParticle()->GetDefinition()->GetPDGLifeTime();
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if (pTime < 0.) {
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// normal case
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if ( previousStepSize > 0.0){
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// subtract NumberOfInteractionLengthLeft
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SubtractNumberOfInteractionLengthLeft(previousStepSize);
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if(theNumberOfInteractionLengthLeft<0.){
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theNumberOfInteractionLengthLeft=perMillion;
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}
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fRemainderLifeTime = theNumberOfInteractionLengthLeft*aLife;
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}
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// get mean free path
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currentInteractionLength = GetMeanFreePath(track, previousStepSize, condition);
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#ifdef G4VERBOSE
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if ((currentInteractionLength <=0.0) || (verboseLevel>2)){
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G4cout << "G4Decay::PostStepGetPhysicalInteractionLength " << G4endl;
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track.GetDynamicParticle()->DumpInfo();
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G4cout << " in Material " << track.GetMaterial()->GetName() <<G4endl;
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G4cout << "MeanFreePath = " << currentInteractionLength/cm << "[cm]" <<G4endl;
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}
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#endif
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G4double value;
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if (currentInteractionLength <DBL_MAX) {
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value = theNumberOfInteractionLengthLeft * currentInteractionLength;
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//fRemainderLifeTime = theNumberOfInteractionLengthLeft*aLife;
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} else {
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value = DBL_MAX;
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}
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return value;
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} else {
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//pre-assigned Decay time case
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// reminder proper time
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fRemainderLifeTime = pTime - track.GetProperTime();
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if (fRemainderLifeTime <= 0.0) fRemainderLifeTime = 0.0;
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G4double rvalue=0.0;
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// use pre-assigned Decay time to determine PIL
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if (aLife>0.0) {
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// ordinary particle
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rvalue = (fRemainderLifeTime/aLife)*GetMeanFreePath(track, previousStepSize, condition);
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} else {
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// shortlived particle
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rvalue = c_light * fRemainderLifeTime;
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// by using normalized kinetic energy (= Ekin/mass)
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G4double aMass = track.GetDynamicParticle()->GetMass();
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rvalue *= track.GetDynamicParticle()->GetTotalMomentum()/aMass;
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}
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return rvalue;
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}
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}
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G4double G4Decay::AtRestGetPhysicalInteractionLength(
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const G4Track& track,
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G4ForceCondition* condition
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)
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{
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// condition is set to "Not Forced"
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*condition = NotForced;
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G4double pTime = track.GetDynamicParticle()->GetPreAssignedDecayProperTime();
|
|
if (pTime >= 0.) {
|
|
fRemainderLifeTime = pTime - track.GetProperTime();
|
|
if (fRemainderLifeTime <= 0.0) fRemainderLifeTime = DBL_MIN;
|
|
} else {
|
|
fRemainderLifeTime =
|
|
theNumberOfInteractionLengthLeft * GetMeanLifeTime(track, condition);
|
|
}
|
|
return fRemainderLifeTime;
|
|
}
|
|
|
|
|
|
void G4Decay::SetExtDecayer(G4VExtDecayer* val)
|
|
{
|
|
pExtDecayer = val;
|
|
|
|
// set Process Sub Type
|
|
if ( pExtDecayer !=0 ) {
|
|
SetProcessSubType(static_cast<int>(DECAY_External));
|
|
}
|
|
}
|
|
|
|
G4VParticleChange* G4Decay::PostStepDoIt(
|
|
const G4Track& aTrack,
|
|
const G4Step& aStep
|
|
)
|
|
{
|
|
if ( (aTrack.GetTrackStatus() == fStopButAlive ) ||
|
|
(aTrack.GetTrackStatus() == fStopAndKill ) ){
|
|
fParticleChangeForDecay.Initialize(aTrack);
|
|
return &fParticleChangeForDecay;
|
|
} else {
|
|
return DecayIt(aTrack, aStep);
|
|
}
|
|
}
|
|
|
|
void G4Decay::ProcessDescription(std::ostream& outFile) const
|
|
{
|
|
outFile << GetProcessName() << ": Decay of particles. \n"
|
|
<< "kinematics of daughters are dertermined by DecayChannels "
|
|
<< " or by PreAssignedDecayProducts\n";
|
|
}
|