Gabriele Cosmo
486 lines
16 KiB
C++
486 lines
16 KiB
C++
// This code implementation is the intellectual property of
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// the 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: G4PhaseSpaceDecayChannel.cc,v 1.4 1999/12/15 14:51:15 gunter Exp $
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// GEANT4 tag $Name: geant4-02-00 $
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//
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//
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// ------------------------------------------------------------
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// GEANT 4 class header 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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// 27 July 1996 H.Kurashige
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// 20 Oct 1996 H.Kurashige
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// 30 May 1997 H.Kurashige
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// ------------------------------------------------------------
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#include "G4ParticleDefinition.hh"
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#include "G4DecayProducts.hh"
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#include "G4VDecayChannel.hh"
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#include "G4PhaseSpaceDecayChannel.hh"
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#include "Randomize.hh"
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#include "G4LorentzVector.hh"
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#include "G4LorentzRotation.hh"
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G4PhaseSpaceDecayChannel::G4PhaseSpaceDecayChannel(G4int Verbose)
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:G4VDecayChannel("Phase Space", Verbose)
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{
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}
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G4PhaseSpaceDecayChannel::G4PhaseSpaceDecayChannel(
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const G4String& theParentName,
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G4double theBR,
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G4int theNumberOfDaughters,
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const G4String& theDaughterName1,
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const G4String& theDaughterName2,
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const G4String& theDaughterName3,
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const G4String& theDaughterName4 )
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:G4VDecayChannel("Phase Space",
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theParentName,theBR,
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theNumberOfDaughters,
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theDaughterName1,
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theDaughterName2,
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theDaughterName3,
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theDaughterName4)
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{
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}
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G4PhaseSpaceDecayChannel::~G4PhaseSpaceDecayChannel()
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{
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}
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G4DecayProducts *G4PhaseSpaceDecayChannel::DecayIt(G4double parentMass)
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{
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) G4cout << "G4PhaseSpaceDecayChannel::DecayIt ";
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#endif
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G4DecayProducts * products = 0;
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if (parent == 0) FillParent();
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if (daughters == 0) FillDaughters();
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if (parentMass >0.0) parent_mass = parentMass;
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switch (numberOfDaughters){
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case 0:
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>0) {
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G4cout << "G4PhaseSpaceDecayChannel::DecayIt ";
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G4cout << " daughters not defined " <<G4endl;
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}
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#endif
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break;
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case 1:
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products = OneBodyDecayIt();
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break;
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case 2:
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products = TwoBodyDecayIt();
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break;
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case 3:
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products = ThreeBodyDecayIt();
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break;
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default:
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products = ManyBodyDecayIt();
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break;
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}
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#ifdef G4VERBOSE
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if ((products == 0) && (GetVerboseLevel()>0)) {
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G4cout << "G4PhaseSpaceDecayChannel::DecayIt ";
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G4cout << *parent_name << " can not decay " << G4endl;
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DumpInfo();
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}
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#endif
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return products;
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}
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G4DecayProducts *G4PhaseSpaceDecayChannel::OneBodyDecayIt()
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{
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) G4cout << "G4PhaseSpaceDecayChannel::OneBodyDecayIt()"<<G4endl;
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#endif
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G4double parentmass = parent_mass;
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G4double daughtermass = daughters_mass[0];
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//create parent G4DynamicParticle at rest
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G4ThreeVector dummy;
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G4DynamicParticle * parentparticle = new G4DynamicParticle( parent, dummy, 0.0);
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//create G4Decayproducts
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G4DecayProducts *products = new G4DecayProducts(*parentparticle);
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delete parentparticle;
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//create daughter G4DynamicParticle at rest
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G4DynamicParticle * daughterparticle = new G4DynamicParticle( daughters[0], dummy, 0.0);
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products->PushProducts(daughterparticle);
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << "G4PhaseSpaceDecayChannel::OneBodyDecayIt ";
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G4cout << " create decay products in rest frame " <<G4endl;
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products->DumpInfo();
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}
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#endif
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return products;
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}
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G4DecayProducts *G4PhaseSpaceDecayChannel::TwoBodyDecayIt()
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{
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) G4cout << "G4PhaseSpaceDecayChannel::TwoBodyDecayIt()"<<G4endl;
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#endif
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// parent mass
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G4double parentmass = parent_mass;
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//daughters'mass
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G4double daughtermass[2];
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G4double daughtermomentum;
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daughtermass[0] = daughters_mass[0];
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daughtermass[1] = daughters_mass[1];
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G4double sumofdaughtermass = daughtermass[0] + daughtermass[1];
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//create parent G4DynamicParticle at rest
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G4ThreeVector dummy;
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G4DynamicParticle * parentparticle = new G4DynamicParticle( parent, dummy, 0.0);
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//create G4Decayproducts
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G4DecayProducts *products = new G4DecayProducts(*parentparticle);
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delete parentparticle;
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//calculate daughter momentum
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daughtermomentum = Pmx(parentmass,daughtermass[0],daughtermass[1]);
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G4double costheta = 2.*G4UniformRand()-1.0;
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G4double sintheta = sqrt((1.0 - costheta)*(1.0 + costheta));
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G4double phi = 2.0*M_PI*G4UniformRand()*rad;
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G4ThreeVector direction(sintheta*cos(phi),sintheta*sin(phi),costheta);
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//create daughter G4DynamicParticle
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G4DynamicParticle * daughterparticle = new G4DynamicParticle( daughters[0], direction*daughtermomentum);
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products->PushProducts(daughterparticle);
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daughterparticle = new G4DynamicParticle( daughters[1], direction*(-1.0*daughtermomentum));
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products->PushProducts(daughterparticle);
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << "G4PhaseSpaceDecayChannel::TwoBodyDecayIt ";
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G4cout << " create decay products in rest frame " <<G4endl;
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products->DumpInfo();
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}
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#endif
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return products;
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}
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G4DecayProducts *G4PhaseSpaceDecayChannel::ThreeBodyDecayIt()
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// algorism of this code is originally written in GDECA3 of GEANT3
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{
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) G4cout << "G4PhaseSpaceDecayChannel::ThreeBodyDecayIt()"<<G4endl;
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#endif
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// parent mass
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G4double parentmass = parent_mass;
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//daughters'mass
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G4double daughtermass[3];
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G4double sumofdaughtermass = 0.0;
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for (G4int index=0; index<3; index++){
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daughtermass[index] = daughters_mass[index];
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sumofdaughtermass += daughtermass[index];
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}
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//create parent G4DynamicParticle at rest
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G4ThreeVector dummy;
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G4DynamicParticle * parentparticle = new G4DynamicParticle( parent, dummy, 0.0);
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//create G4Decayproducts
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G4DecayProducts *products = new G4DecayProducts(*parentparticle);
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delete parentparticle;
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//calculate daughter momentum
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// Generate two
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G4double rd1, rd2, rd;
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G4double daughtermomentum[3];
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G4double momentummax=0.0, momentumsum = 0.0;
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G4double energy;
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do {
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rd1 = G4UniformRand();
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rd2 = G4UniformRand();
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if (rd2 > rd1) {
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rd = rd1;
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rd1 = rd2;
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rd2 = rd;
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}
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momentummax = 0.0;
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momentumsum = 0.0;
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// daughter 0
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energy = rd2*(parentmass - sumofdaughtermass);
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daughtermomentum[0] = sqrt(energy*energy + 2.0*energy* daughtermass[0]);
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if ( daughtermomentum[0] >momentummax )momentummax = daughtermomentum[0];
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momentumsum += daughtermomentum[0];
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// daughter 1
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energy = (1.-rd1)*(parentmass - sumofdaughtermass);
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daughtermomentum[1] = sqrt(energy*energy + 2.0*energy* daughtermass[1]);
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if ( daughtermomentum[1] >momentummax )momentummax = daughtermomentum[1];
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momentumsum += daughtermomentum[1];
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// daughter 2
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energy = (rd1-rd2)*(parentmass - sumofdaughtermass);
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daughtermomentum[2] = sqrt(energy*energy + 2.0*energy* daughtermass[2]);
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if ( daughtermomentum[2] >momentummax )momentummax = daughtermomentum[2];
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momentumsum += daughtermomentum[2];
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} while (momentummax > momentumsum - momentummax );
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// output message
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << " daughter 0:" << daughtermomentum[0]/GeV << "[GeV/c]" <<G4endl;
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G4cout << " daughter 1:" << daughtermomentum[1]/GeV << "[GeV/c]" <<G4endl;
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G4cout << " daughter 2:" << daughtermomentum[2]/GeV << "[GeV/c]" <<G4endl;
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G4cout << " momentum sum:" << momentumsum/GeV << "[GeV/c]" <<G4endl;
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}
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#endif
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//create daughter G4DynamicParticle
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G4double costheta, sintheta, phi, sinphi, cosphi;
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G4double costhetan, sinthetan, phin, sinphin, cosphin;
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costheta = 2.*G4UniformRand()-1.0;
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sintheta = sqrt((1.0-costheta)*(1.0+costheta));
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phi = 2.0*M_PI*G4UniformRand()*rad;
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sinphi = sin(phi);
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cosphi = cos(phi);
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G4ThreeVector direction0(sintheta*cosphi,sintheta*sinphi,costheta);
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G4DynamicParticle * daughterparticle
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= new G4DynamicParticle( daughters[0], direction0*daughtermomentum[0]);
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products->PushProducts(daughterparticle);
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costhetan = (daughtermomentum[1]*daughtermomentum[1]-daughtermomentum[2]*daughtermomentum[2]-daughtermomentum[0]*daughtermomentum[0])/(2.0*daughtermomentum[2]*daughtermomentum[0]);
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sinthetan = sqrt((1.0-costhetan)*(1.0+costhetan));
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phin = 2.0*M_PI*G4UniformRand()*rad;
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sinphin = sin(phin);
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cosphin = cos(phin);
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G4ThreeVector direction2;
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direction2.setX( sinthetan*cosphin*costheta*cosphi - sinthetan*sinphin*sinphi + costhetan*sintheta*cosphi);
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direction2.setY( sinthetan*cosphin*costheta*sinphi + sinthetan*sinphin*cosphi + costhetan*sintheta*sinphi);
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direction2.setZ( -sinthetan*cosphin*sintheta + costhetan*costheta);
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daughterparticle = new G4DynamicParticle( daughters[2], direction2*(daughtermomentum[2]/direction2.mag()));
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products->PushProducts(daughterparticle);
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daughterparticle =
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new G4DynamicParticle(
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daughters[1],
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(direction0*daughtermomentum[0] + direction2*(daughtermomentum[2]/direction2.mag()))*(-1.0)
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);
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products->PushProducts(daughterparticle);
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << "G4PhaseSpaceDecayChannel::ThreeBodyDecayIt ";
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G4cout << " create decay products in rest frame " <<G4endl;
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products->DumpInfo();
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}
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#endif
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return products;
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}
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G4DecayProducts *G4PhaseSpaceDecayChannel::ManyBodyDecayIt()
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// algorithm of this code is originally written in FORTRAN by M.Asai
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//******************************************************************
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// NBODY
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// N-body phase space Monte-Carlo generator
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// Makoto Asai
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// Hiroshima Institute of Technology
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// (asai@kekvax.kek.jp)
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// Revised release : 19/Apr/1995
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//
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{
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G4int index, index2;
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//return value
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G4DecayProducts *products;
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) G4cout << "G4PhaseSpaceDecayChannel::ManyBodyDecayIt()"<<G4endl;
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#endif
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// parent mass
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G4double parentmass = parent_mass;
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//daughters'mass
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G4double *daughtermass = new G4double[numberOfDaughters];
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G4double sumofdaughtermass = 0.0;
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for (index=0; index<numberOfDaughters; index++){
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daughtermass[index] = daughters_mass[index];
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sumofdaughtermass += daughtermass[index];
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}
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//Calculate daughter momentum
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G4double *daughtermomentum = new G4double[numberOfDaughters];
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G4ThreeVector direction;
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G4DynamicParticle **daughterparticle;
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G4double *sm = new G4double[numberOfDaughters];
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G4double tmas;
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G4double weight = 1.0;
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G4int numberOfTry = 0;
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do {
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//Generate rundom number in descending order
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G4double temp;
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G4double *rd = new G4double[numberOfDaughters];
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rd[0] = 1.0;
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for(index =1; index < numberOfDaughters -1; index++) rd[index] = G4UniformRand();
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rd[ numberOfDaughters -1] = 0.0;
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for(index =1; index < numberOfDaughters -1; index++) {
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for(index2 = index+1; index2 < numberOfDaughters; index2++) {
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if (rd[index] < rd[index2]){
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temp = rd[index];
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rd[index] = rd[index2];
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rd[index2] = temp;
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}
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}
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}
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//calcurate virtual mass
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tmas = parentmass - sumofdaughtermass;
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temp = sumofdaughtermass;
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for(index =0; index < numberOfDaughters; index++) {
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sm[index] = rd[index]*tmas + temp;
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temp -= daughtermass[index];
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if (GetVerboseLevel()>1) {
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G4cout << index << " rundom number:" << rd[index];
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G4cout << " virtual mass:" << sm[index]/GeV << "[GeV/c/c]" <<G4endl;
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}
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}
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delete [] rd;
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//Calculate daughter momentum
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weight = 1.0;
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index =numberOfDaughters-1;
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daughtermomentum[index]= Pmx( sm[index-1],daughtermass[index-1], sm[index]);
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << " daughter " << index << ":" << *daughters_name[index];
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G4cout << " momentum:" << daughtermomentum[index]/GeV << "[GeV/c]" <<G4endl;
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}
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#endif
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for(index =numberOfDaughters-2; index>=0; index--) {
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// calculate
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daughtermomentum[index]= Pmx( sm[index],daughtermass[index], sm[index +1]);
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if(daughtermomentum[index] < 0.0) {
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// !!! illegal momentum !!!
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>0) {
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G4cout << "G4PhaseSpaceDecayChannel::ManyBodyDecayIt ";
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G4cout << " can not calculate daughter momentum " <<G4endl;
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G4cout << " parent:" << *parent_name;
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G4cout << " mass:" << parentmass/GeV << "[GeV/c/c]" <<G4endl;
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G4cout << " daughter " << index << ":" << *daughters_name[index];
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G4cout << " mass:" << daughtermass[index]/GeV << "[GeV/c/c]" ;
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G4cout << " mass:" << daughtermomentum[index]/GeV << "[GeV/c]" <<G4endl;
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}
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#endif
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delete [] sm;
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delete [] daughtermass;
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delete [] daughtermomentum;
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return 0; // Error detection
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} else {
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// calculate weight of this events
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weight *= daughtermomentum[index]/sm[index];
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if (GetVerboseLevel()>1) {
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G4cout << " daughter " << index << ":" << *daughters_name[index];
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G4cout << " momentum:" << daughtermomentum[index]/GeV << "[GeV/c]" <<G4endl;
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}
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}
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}
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if (GetVerboseLevel()>1) {
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G4cout << " weight: " << weight <<G4endl;
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}
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// exit if number of Try exceeds 100
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if (numberOfTry++ >100) {
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if (GetVerboseLevel()>0) {
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G4cout << "G4PhaseSpaceDecayChannel::ManyBodyDecayIt: ";
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G4cout << " can not determine Decay Kinematics " << G4endl;
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}
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delete [] sm;
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delete [] daughtermass;
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delete [] daughtermomentum;
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return 0; // Error detection
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}
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} while ( weight > G4UniformRand());
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#ifdef G4VERBOSE
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if (GetVerboseLevel()>1) {
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G4cout << "Start calulation of daughters momentum vector "<<G4endl;
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}
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#endif
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G4double costheta, sintheta, phi;
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G4double beta;
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daughterparticle = new G4DynamicParticle*[numberOfDaughters];
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index = numberOfDaughters -2;
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costheta = 2.*G4UniformRand()-1.0;
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sintheta = sqrt((1.0-costheta)*(1.0+costheta));
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phi = 2.0*M_PI*G4UniformRand()*rad;
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direction.setZ(costheta);
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direction.setY(sintheta*sin(phi));
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direction.setX(sintheta*cos(phi));
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daughterparticle[index] = new G4DynamicParticle( daughters[index], direction*daughtermomentum[index] );
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daughterparticle[index+1] = new G4DynamicParticle( daughters[index+1], direction*(-1.0*daughtermomentum[index]) );
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for (index = numberOfDaughters -3; index >= 0; index--) {
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//calculate momentum direction
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costheta = 2.*G4UniformRand()-1.0;
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sintheta = sqrt((1.0-costheta)*(1.0+costheta));
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phi = 2.0*M_PI*G4UniformRand()*rad;
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direction.setZ(costheta);
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direction.setY(sintheta*sin(phi));
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direction.setX(sintheta*cos(phi));
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// boost already created particles
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beta = daughtermomentum[index];
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beta /= sqrt( daughtermomentum[index]*daughtermomentum[index] + sm[index+1]*sm[index+1] );
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for (G4int index2 = index+1; index2<numberOfDaughters; index2++) {
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G4LorentzVector p4;
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// make G4LorentzVector for secondaries
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p4 = daughterparticle[index2]->Get4Momentum();
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// boost secondaries to new frame
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p4.boost( direction.x()*beta, direction.y()*beta, direction.z()*beta);
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// change energy/momentum
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daughterparticle[index2]->Set4Momentum(p4);
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}
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//create daughter G4DynamicParticle
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daughterparticle[index]= new G4DynamicParticle( daughters[index], direction*(-1.0*daughtermomentum[index]));
|
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}
|
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|
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//create G4Decayproducts
|
|
G4DynamicParticle *parentparticle;
|
|
direction.setX(1.0); direction.setY(0.0); direction.setZ(0.0);
|
|
parentparticle = new G4DynamicParticle( parent, direction, 0.0);
|
|
products = new G4DecayProducts(*parentparticle);
|
|
delete parentparticle;
|
|
for (index = 0; index<numberOfDaughters; index++) {
|
|
products->PushProducts(daughterparticle[index]);
|
|
}
|
|
#ifdef G4VERBOSE
|
|
if (GetVerboseLevel()>1) {
|
|
G4cout << "G4PhaseSpaceDecayChannel::ManyBodyDecayIt ";
|
|
G4cout << " create decay products in rest frame " << G4endl;
|
|
products->DumpInfo();
|
|
}
|
|
#endif
|
|
delete [] daughterparticle;
|
|
delete [] daughtermomentum;
|
|
delete [] daughtermass;
|
|
delete [] sm;
|
|
|
|
return products;
|
|
}
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