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36c080dca608e34725b7089dbe1cb775a1de8e22
geant4/source/processes/decay/src/G4Decay.cc
T
Gabriele Cosmo 36c080dca6 Import Geant4 3.2.0 source tree
2016-06-08 16:10:37 +02:00

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//
// ********************************************************************
// * DISCLAIMER *
// * *
// * The following disclaimer summarizes all the specific disclaimers *
// * of contributors to this software. The specific disclaimers,which *
// * govern, are listed with their locations in: *
// * http://cern.ch/geant4/license *
// * *
// * 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. *
// * *
// * This code implementation is the intellectual property of the *
// * GEANT4 collaboration. *
// * By copying, distributing or modifying the Program (or any work *
// * based on the Program) you indicate your acceptance of this *
// * statement, and all its terms. *
// ********************************************************************
//
//
// $Id: G4Decay.cc,v 1.8.2.2 2001/06/28 20:19:17 gunter Exp $
// GEANT4 tag $Name: $
//
//
// --------------------------------------------------------------
// GEANT 4 class implementation file
//
// History: first implementation, based on object model of
// 2nd December 1995, G.Cosmo
// 7 July 1996 H.Kurashige
// ------------------------------------------------------------
// remove BuildPhysicsTable() 28 Nov. 1997 H.Kurashige
// change DBL_EPSIRON to DBL_MIN 14 Dec. 1997 H.Kurashige
// modified for new ParticleChange 12 Mar. 1998 H.Kurashige
// modified for "GoodForTrackingFlag" 19 June 1998 H.Kurashige
// rename thePhysicsTable to aPhyscisTable 2 Aug. 1998 H.Kurashige
// modified IsApplicable in order to protect the decay from registered
// to resonances 12 Dec. 1998 H.Kurashige
// remove G4ParticleMomentum 6 Feb. 99 H.Kurashige
// modified IsApplicable to activate G4Decay for resonances 1 Mar. 00 H.Kurashige
// Add External Decayer 23 Feb. 2001 H.Kurashige
//
#include "G4Decay.hh"
#include "G4DynamicParticle.hh"
#include "G4DecayProducts.hh"
#include "G4DecayTable.hh"
#include "G4PhysicsLogVector.hh"
#include "G4ParticleChangeForDecay.hh"
#include "G4VExtDecayer.hh"
// constructor
G4Decay::G4Decay(const G4String& processName)
:G4VRestDiscreteProcess(processName, fDecay),
HighestBinValue(10.0),
LowestBinValue(1.0e-3),
TotBin(200),
verboseLevel(1),
pExtDecayer(0),
aPhysicsTable(0)
{
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
G4cerr << "G4Decay constructor " << " Name:" << processName << G4endl;
}
#endif
pParticleChange = &fParticleChangeForDecay;
}
G4Decay::~G4Decay()
{
if (aPhysicsTable != 0) {
aPhysicsTable->clearAndDestroy();
delete aPhysicsTable;
}
if (pExtDecayer) {
delete pExtDecayer;
}
}
G4bool G4Decay::IsApplicable(const G4ParticleDefinition& aParticleType)
{
// check if the particle is stable?
if (aParticleType.GetPDGLifeTime() <0.0) {
return false;
} else if (aParticleType.GetPDGMass() <= 0.0*MeV) {
return false;
} else {
return true;
}
}
G4double G4Decay::GetMeanLifeTime(const G4Track& aTrack,
G4ForceCondition*)
{
// get particle type
const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle();
// returns the mean free path in GEANT4 internal units
G4double meanlife;
G4ParticleDefinition* aParticleDef = aParticle->GetDefinition();
G4double aLife = aParticleDef->GetPDGLifeTime();
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
G4cerr << "G4Decay::GetMeanLifeTime() "<< G4endl;
G4cerr << "KineticEnergy:" << aParticle->GetKineticEnergy()/GeV <<"[GeV]";
G4cerr << "Mass:" << aParticle->GetMass()/GeV <<"[GeV]";
G4cerr << "Life time: "<< aLife/ns << "[ns]" << G4endl;
}
#endif
// check if the particle is stable?
if (aParticleDef->GetPDGStable()) {
meanlife = DBL_MAX;
} else if (aLife < 0.0) {
meanlife = DBL_MAX;
} else {
meanlife = aLife;
}
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
G4cerr << "mean life time: "<< meanlife/ns << "[ns]" << G4endl;
}
#endif
return meanlife;
}
G4double G4Decay::GetMeanFreePath(const G4Track& aTrack,G4double, G4ForceCondition*)
{
// constants
G4bool isOutRange ;
// get particle
const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle();
// returns the mean free path in GEANT4 internal units
G4double pathlength;
G4ParticleDefinition* aParticleDef = aParticle->GetDefinition();
G4double aCtau = c_light * aParticleDef->GetPDGLifeTime();
G4double aMass = aParticle->GetMass();
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
G4cerr << "G4Decay::GetMeanFreePath() "<< G4endl;
G4cerr << "KineticEnergy:" << aParticle->GetKineticEnergy()/GeV <<"[GeV]";
G4cerr << "Mass:" << aMass/GeV <<"[GeV]";
G4cerr << "c*Tau:" << aCtau/m <<"[m]" <<G4endl;
}
#endif
// check if the particle is stable?
if (aParticleDef->GetPDGStable()) {
pathlength = DBL_MAX;
} else if (aCtau < 0.0) {
pathlength = DBL_MAX;
//check if the particle has very short life time ?
} else if (aCtau < DBL_MIN) {
pathlength = DBL_MIN;
//check if zero mass
} else if (aMass < DBL_MIN) {
pathlength = DBL_MAX;
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
G4cerr << " Zero Mass particle " << G4endl;
}
#endif
} else {
//calculate the mean free path
// by using normalized kinetic energy (= Ekin/mass)
G4double rKineticEnergy = aParticle->GetKineticEnergy()/aMass;
if ( rKineticEnergy > HighestBinValue) {
// beta >> 1
pathlength = ( rKineticEnergy + 1.0)* aCtau;
} else if ( rKineticEnergy > LowestBinValue) {
// check if aPhysicsTable exists
if (aPhysicsTable == NULL) BuildPhysicsTable(*aParticleDef);
// beta is in the range valid for PhysicsTable
pathlength = aCtau *
((*aPhysicsTable)(0))-> GetValue(rKineticEnergy,isOutRange);
} else if ( rKineticEnergy < DBL_MIN ) {
// too slow particle
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
G4cerr << "G4Decay::GetMeanFreePath() !!particle stops!!";
G4cerr << aParticleDef->GetParticleName() << G4endl;
G4cerr << "KineticEnergy:" << aParticle->GetKineticEnergy()/GeV <<"[GeV]";
}
#endif
pathlength = DBL_MIN;
} else {
// beta << 1
pathlength = (aParticle->GetTotalMomentum())/aMass*aCtau ;
}
}
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
G4cerr << "mean free path: "<< pathlength/m << "[m]" << G4endl;
}
#endif
return pathlength;
}
void G4Decay::BuildPhysicsTable(const G4ParticleDefinition&)
{
// if aPhysicsTableis has already been created, do nothing
if (aPhysicsTable != NULL) return;
// create aPhysicsTable
if (GetVerboseLevel()>1) G4cerr <<" G4Decay::BuildPhysicsTable() "<< G4endl;
aPhysicsTable = new G4PhysicsTable(1);
//create physics vector
G4PhysicsLogVector* aVector = new G4PhysicsLogVector(
LowestBinValue,
HighestBinValue,
TotBin);
G4double beta, gammainv;
// fill physics Vector
G4int i;
for ( i = 0 ; i < TotBin ; i++ ) {
gammainv = 1.0/(aVector->GetLowEdgeEnergy(i) + 1.0);
beta = sqrt((1.0 - gammainv)*(1.0 +gammainv));
aVector->PutValue(i, beta/gammainv);
}
aPhysicsTable->insert(aVector);
}
G4VParticleChange* G4Decay::DecayIt(const G4Track& aTrack, const G4Step& )
{
// The DecayIt() method returns by pointer a particle-change object.
// Units are expressed in GEANT4 internal units.
// Initialize ParticleChange
// all members of G4VParticleChange are set to equal to
// corresponding member in G4Track
fParticleChangeForDecay.Initialize(aTrack);
// get particle
const G4DynamicParticle* aParticle = aTrack.GetDynamicParticle();
G4ParticleDefinition* aParticleDef = aParticle->GetDefinition();
// check if the particle is stable
if (aParticleDef->GetPDGStable()) return &fParticleChangeForDecay ;
//check if thePreAssignedDecayProducts exists
const G4DecayProducts* o_products = (aParticle->GetPreAssignedDecayProducts());
G4bool isPreAssigned = (o_products != 0);
G4DecayProducts* products = 0;
// decay table
G4DecayTable *decaytable = aParticleDef->GetDecayTable();
// check if external decayer exists
G4bool isExtDecayer = (decaytable == 0) && (pExtDecayer !=0);
// Error due to NO Decay Table
if ( (decaytable == 0) && !isExtDecayer &&!isPreAssigned ){
#ifdef G4VERBOSE
if (GetVerboseLevel()>0) {
G4cerr << "G4Decay::DoIt : decay table not defined for ";
G4cerr << aParticle->GetDefinition()->GetParticleName()<< G4endl;
}
#endif
fParticleChangeForDecay.SetNumberOfSecondaries(0);
// Kill the parent particle
fParticleChangeForDecay.SetStatusChange( fStopAndKill ) ;
fParticleChangeForDecay.SetLocalEnergyDeposit(0.0);
ClearNumberOfInteractionLengthLeft();
return &fParticleChangeForDecay ;
}
if (isPreAssigned) {
// copy decay products
products = new G4DecayProducts(*o_products);
} else if ( isExtDecayer ) {
// decay according to external decayer
products = pExtDecayer->ImportDecayProducts(aTrack);
} else {
// decay acoording to decay table
// choose a decay channel
G4VDecayChannel *decaychannel = decaytable->SelectADecayChannel();
if (decaychannel == 0 ){
// decay channel not found
G4Exception("G4Decay::DoIt : can not determine decay channel ");
} else {
G4int temp;
// execute DecayIt()
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
G4cerr << "G4Decay::DoIt : selected decay channel addr:" << decaychannel <<G4endl;
temp = decaychannel->GetVerboseLevel();
decaychannel->SetVerboseLevel(GetVerboseLevel());
}
#endif
products = decaychannel->DecayIt(aParticle->GetMass());
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
decaychannel->SetVerboseLevel(temp);
}
#endif
#ifdef G4VERBOSE
// for debug
//if (! products->IsChecked() ) products->DumpInfo();
#endif
}
}
// get parent particle information ...................................
G4double ParentEnergy = aParticle->GetTotalEnergy();
G4ThreeVector ParentDirection(aParticle->GetMomentumDirection());
//boost all decay products to laboratory frame
G4double energyDeposit = 0.0;
G4double finalGlobalTime = aTrack.GetGlobalTime();
if (aTrack.GetTrackStatus() == fStopButAlive ){
// AtRest case
finalGlobalTime += fRemainderLifeTime;
energyDeposit += aParticle->GetKineticEnergy();
if (isPreAssigned) products->Boost( ParentEnergy, ParentDirection);
} else {
// PostStep case
if (!isExtDecayer) products->Boost( ParentEnergy, ParentDirection);
}
//add products in fParticleChangeForDecay
G4int numberOfSecondaries = products->entries();
fParticleChangeForDecay.SetNumberOfSecondaries(numberOfSecondaries);
#ifdef G4VERBOSE
if (GetVerboseLevel()>1) {
G4cerr << "G4Decay::DoIt : Decay vertex :";
G4cerr << " Time: " << finalGlobalTime/ns << "[ns]";
G4cerr << " X:" << (aTrack.GetPosition()).x() /cm << "[cm]";
G4cerr << " Y:" << (aTrack.GetPosition()).y() /cm << "[cm]";
G4cerr << " Z:" << (aTrack.GetPosition()).z() /cm << "[cm]";
G4cerr << G4endl;
G4cerr << "G4Decay::DoIt : decay products in Lab. Frame" << G4endl;
products->DumpInfo();
}
#endif
G4int index;
G4ThreeVector currentPosition;
for (index=0; index < numberOfSecondaries; index++)
{
// get current position of the track
currentPosition = aTrack.GetPosition();
// create a new track object
G4Track* secondary = new G4Track( products->PopProducts(),
finalGlobalTime ,
currentPosition );
// switch on good for tracking flag
secondary->SetGoodForTrackingFlag();
// add the secondary track in the List
fParticleChangeForDecay.AddSecondary(secondary);
}
delete products;
// Kill the parent particle
fParticleChangeForDecay.SetStatusChange( fStopAndKill ) ;
fParticleChangeForDecay.SetLocalEnergyDeposit(energyDeposit);
fParticleChangeForDecay.SetTimeChange( finalGlobalTime );
// reset NumberOfInteractionLengthLeft
ClearNumberOfInteractionLengthLeft();
return &fParticleChangeForDecay ;
}
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