Gabriele Cosmo
353 lines
11 KiB
C++
353 lines
11 KiB
C++
// This code implementation is the intellectual property of
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// the RD44 GEANT4 collaboration.
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//
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// By copying, distributing or modifying the Program (or any work
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// based on the Program) you indicate your acceptance of this statement,
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// and all its terms.
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//
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// $Id: G4Decay.cc,v 2.5 1998/12/15 09:40:26 kurasige Exp $
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// GEANT4 tag $Name: geant4-00 $
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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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// For information related to this code contact:
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// CERN, CN Division, ASD group
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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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#include "G4Decay.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 "G4PhysicsLogVector.hh"
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#include "G4ParticleChangeForDecay.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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HighestBinValue(10.0),
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LowestBinValue(1.0e-3),
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TotBin(200),
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verboseLevel(1)
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{
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cerr << "G4Decay constructor " << " Name:" << processName << endl;
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}
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#endif
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aPhysicsTable = NULL;
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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 (aPhysicsTable != NULL) {
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aPhysicsTable->clearAndDestroy();
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delete aPhysicsTable;
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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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// return false if resonances
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if (aParticleType.IsShortLived()) return false;
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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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// get particle type
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const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle();
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// returns the mean free path in GEANT4 internal units
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G4double meanlife;
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G4ParticleDefinition* aParticleDef = aParticle->GetDefinition();
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G4double aLife = aParticleDef->GetPDGLifeTime();
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cerr << "G4Decay::GetMeanLifeTime() "<< endl;
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G4cerr << "KineticEnergy:" << aParticle->GetKineticEnergy()/GeV <<"[GeV]";
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G4cerr << "Mass:" << aParticle->GetMass()/GeV <<"[GeV]";
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G4cerr << "Life time: "<< aLife/ns << "[ns]" << endl;
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}
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#endif
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// check if the particle is stable?
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if (aParticleDef->GetPDGStable()) {
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meanlife = DBL_MAX;
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} else if (aLife < 0.0) {
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meanlife = DBL_MAX;
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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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G4cerr << "mean life time: "<< meanlife/ns << "[ns]" << endl;
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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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// constants
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G4bool isOutRange ;
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// get particle
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const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle();
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// returns the mean free path in GEANT4 internal units
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G4double pathlength;
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G4ParticleDefinition* aParticleDef = aParticle->GetDefinition();
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G4double aCtau = c_light * aParticleDef->GetPDGLifeTime();
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G4double aMass = aParticle->GetMass();
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cerr << "G4Decay::GetMeanFreePath() "<< endl;
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G4cerr << "KineticEnergy:" << aParticle->GetKineticEnergy()/GeV <<"[GeV]";
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G4cerr << "Mass:" << aMass/GeV <<"[GeV]";
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G4cerr << "c*Tau:" << aCtau/m <<"[m]" <<endl;
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}
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#endif
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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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} else if (aCtau < 0.0) {
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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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//check if zero mass
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} else if (aMass < DBL_MIN) {
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pathlength = DBL_MAX;
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cerr << " Zero Mass particle " << endl;
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}
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#endif
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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 > HighestBinValue) {
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// beta >> 1
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pathlength = ( rKineticEnergy + 1.0)* aCtau;
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} else if ( rKineticEnergy > LowestBinValue) {
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// check if aPhysicsTable exists
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if (aPhysicsTable == NULL) BuildPhysicsTable(*aParticleDef);
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// beta is in the range valid for PhysicsTable
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pathlength = aCtau *
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((*aPhysicsTable)(0))-> GetValue(rKineticEnergy,isOutRange);
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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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G4cerr << "G4Decay::GetMeanFreePath() !!particle stops!!";
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G4cerr << aParticleDef->GetParticleName() << endl;
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G4cerr << "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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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cerr << "mean free path: "<< pathlength/m << "[m]" << endl;
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}
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#endif
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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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// if aPhysicsTableis has already been created, do nothing
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if (aPhysicsTable != NULL) return;
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// create aPhysicsTable
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if (GetVerboseLevel()>1) G4cerr <<" G4Decay::BuildPhysicsTable() "<< endl;
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aPhysicsTable = new G4PhysicsTable(1);
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//create physics vector
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G4PhysicsLogVector* aVector = new G4PhysicsLogVector(
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LowestBinValue,
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HighestBinValue,
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TotBin);
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G4double beta, gammainv;
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// fill physics Vector
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G4int i;
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for ( i = 0 ; i < TotBin ; i++ ) {
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gammainv = 1.0/(aVector->GetLowEdgeEnergy(i) + 1.0);
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beta = sqrt((1.0 - gammainv)*(1.0 +gammainv));
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aVector->PutValue(i, beta/gammainv);
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}
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aPhysicsTable->insert(aVector);
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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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//check if thePreAssignedDecayProducts exists
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G4DecayProducts* products = aParticle->GetPreAssignedDecayProducts();
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G4bool isPreAssigned = (products != NULL);
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if (!isPreAssigned) {
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// decay acoording to decay table
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G4DecayTable *decaytable = aParticle->GetDefinition()->GetDecayTable();
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if (decaytable == NULL){
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>0) {
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G4cerr << "G4Decay::DoIt : decay table not defined for";
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G4cerr << aParticle->GetDefinition()->GetParticleName()<< endl;
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}
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#endif
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fParticleChangeForDecay.SetNumberOfSecondaries(0);
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// Kill the parent particle
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fParticleChangeForDecay.SetStatusChange( fStopAndKill ) ;
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fParticleChangeForDecay.SetLocalEnergyDeposit(0.0);
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ClearNumberOfInteractionLengthLeft();
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return &fParticleChangeForDecay ;
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} else {
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// choose a decay channel
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G4VDecayChannel *decaychannel = decaytable->SelectADecayChannel();
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if (decaychannel == NULL){
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// decay channel not found
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>0) {
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G4cerr << "G4Decay::DoIt : can not determine decay channel " <<endl;
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decaytable ->DumpInfo();
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}
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#endif
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} else {
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G4int temp;
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// execute DecayIt()
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cerr << "G4Decay::DoIt : selected decay channel addr:" << decaychannel <<endl;
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temp = decaychannel->GetVerboseLevel();
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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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// for debug
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//if (! products->IsChecked() ) products->DumpInfo();
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#endif
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}
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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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G4ParticleMomentum 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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if (aTrack.GetTrackStatus() == fStopButAlive ){
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// AtRest case
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finalGlobalTime += fRemainderLifeTime;
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energyDeposit += aParticle->GetKineticEnergy();
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} else {
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// PostStep case
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products->Boost( ParentEnergy, ParentDirection);
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}
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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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G4cerr << "G4Decay::DoIt : Decay vertex :";
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G4cerr << " Time: " << finalGlobalTime/ns << "[ns]";
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G4cerr << " X:" << (aTrack.GetPosition()).x() /cm << "[cm]";
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G4cerr << " Y:" << (aTrack.GetPosition()).y() /cm << "[cm]";
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G4cerr << " Z:" << (aTrack.GetPosition()).z() /cm << "[cm]";
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G4cerr << endl;
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G4cerr << "G4Decay::DoIt : decay products in Lab. Frame" << endl;
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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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for (index=0; index < numberOfSecondaries; index++)
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{
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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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// add the secondary track in the List
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fParticleChangeForDecay.AddSecondary(secondary);
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}
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if (!isPreAssigned) delete products;
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// Kill the parent particle
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fParticleChangeForDecay.SetStatusChange( fStopAndKill ) ;
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fParticleChangeForDecay.SetLocalEnergyDeposit(energyDeposit);
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fParticleChangeForDecay.SetTimeChange( finalGlobalTime );
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// reset NumberOfInteractionLengthLeft
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ClearNumberOfInteractionLengthLeft();
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return &fParticleChangeForDecay ;
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}
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