Gabriele Cosmo
408 lines
14 KiB
C++
408 lines
14 KiB
C++
//
|
|
// ********************************************************************
|
|
// * License and Disclaimer *
|
|
// * *
|
|
// * The Geant4 software is copyright of the Copyright Holders of *
|
|
// * the Geant4 Collaboration. It is provided under the terms and *
|
|
// * conditions of the Geant4 Software License, included in the file *
|
|
// * LICENSE and available at http://cern.ch/geant4/license . These *
|
|
// * include a list of copyright holders. *
|
|
// * *
|
|
// * Neither the authors of this software system, nor their employing *
|
|
// * institutes,nor the agencies providing financial support for this *
|
|
// * work make any representation or warranty, express or implied, *
|
|
// * regarding this software system or assume any liability for its *
|
|
// * use. Please see the license in the file LICENSE and URL above *
|
|
// * for the full disclaimer and the limitation of liability. *
|
|
// * *
|
|
// * This code implementation is the result of the scientific and *
|
|
// * technical work of the GEANT4 collaboration. *
|
|
// * By using, copying, modifying or distributing the software (or *
|
|
// * any work based on the software) you agree to acknowledge its *
|
|
// * use in resulting scientific publications, and indicate your *
|
|
// * acceptance of all terms of the Geant4 Software license. *
|
|
// ********************************************************************
|
|
//
|
|
//
|
|
// $Id: G4RPGKPlusInelastic.cc 94214 2015-11-09 08:18:05Z gcosmo $
|
|
//
|
|
|
|
#include "G4RPGKPlusInelastic.hh"
|
|
#include "G4Exp.hh"
|
|
#include "G4PhysicalConstants.hh"
|
|
#include "G4SystemOfUnits.hh"
|
|
#include "Randomize.hh"
|
|
|
|
G4HadFinalState*
|
|
G4RPGKPlusInelastic::ApplyYourself( const G4HadProjectile &aTrack,
|
|
G4Nucleus &targetNucleus )
|
|
{
|
|
const G4HadProjectile *originalIncident = &aTrack;
|
|
if (originalIncident->GetKineticEnergy()<= 0.1*MeV)
|
|
{
|
|
theParticleChange.SetStatusChange(isAlive);
|
|
theParticleChange.SetEnergyChange(aTrack.GetKineticEnergy());
|
|
theParticleChange.SetMomentumChange(aTrack.Get4Momentum().vect().unit());
|
|
return &theParticleChange;
|
|
}
|
|
|
|
// create the target particle
|
|
|
|
G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
|
|
G4ReactionProduct targetParticle( originalTarget->GetDefinition() );
|
|
|
|
if( verboseLevel > 1 )
|
|
{
|
|
const G4Material *targetMaterial = aTrack.GetMaterial();
|
|
G4cout << "G4RPGKPlusInelastic::ApplyYourself called" << G4endl;
|
|
G4cout << "kinetic energy = " << originalIncident->GetKineticEnergy() << "MeV, ";
|
|
G4cout << "target material = " << targetMaterial->GetName() << ", ";
|
|
G4cout << "target particle = " << originalTarget->GetDefinition()->GetParticleName()
|
|
<< G4endl;
|
|
}
|
|
|
|
G4ReactionProduct currentParticle(originalIncident->GetDefinition() );
|
|
currentParticle.SetMomentum( originalIncident->Get4Momentum().vect() );
|
|
currentParticle.SetKineticEnergy( originalIncident->GetKineticEnergy() );
|
|
|
|
// Fermi motion and evaporation
|
|
// As of Geant3, the Fermi energy calculation had not been Done
|
|
|
|
G4double ek = originalIncident->GetKineticEnergy();
|
|
G4double amas = originalIncident->GetDefinition()->GetPDGMass();
|
|
|
|
G4double tkin = targetNucleus.Cinema( ek );
|
|
ek += tkin;
|
|
currentParticle.SetKineticEnergy( ek );
|
|
G4double et = ek + amas;
|
|
G4double p = std::sqrt( std::abs((et-amas)*(et+amas)) );
|
|
G4double pp = currentParticle.GetMomentum().mag();
|
|
if( pp > 0.0 )
|
|
{
|
|
G4ThreeVector momentum = currentParticle.GetMomentum();
|
|
currentParticle.SetMomentum( momentum * (p/pp) );
|
|
}
|
|
|
|
// calculate black track energies
|
|
|
|
tkin = targetNucleus.EvaporationEffects( ek );
|
|
ek -= tkin;
|
|
currentParticle.SetKineticEnergy( ek );
|
|
et = ek + amas;
|
|
p = std::sqrt( std::abs((et-amas)*(et+amas)) );
|
|
pp = currentParticle.GetMomentum().mag();
|
|
if( pp > 0.0 )
|
|
{
|
|
G4ThreeVector momentum = currentParticle.GetMomentum();
|
|
currentParticle.SetMomentum( momentum * (p/pp) );
|
|
}
|
|
|
|
G4ReactionProduct modifiedOriginal = currentParticle;
|
|
|
|
currentParticle.SetSide( 1 ); // incident always goes in forward hemisphere
|
|
targetParticle.SetSide( -1 ); // target always goes in backward hemisphere
|
|
G4bool incidentHasChanged = false;
|
|
G4bool targetHasChanged = false;
|
|
G4bool quasiElastic = false;
|
|
G4FastVector<G4ReactionProduct,GHADLISTSIZE> vec; // vec will contain the secondary particles
|
|
G4int vecLen = 0;
|
|
vec.Initialize( 0 );
|
|
|
|
const G4double cutOff = 0.1*MeV;
|
|
if( currentParticle.GetKineticEnergy() > cutOff )
|
|
Cascade( vec, vecLen,
|
|
originalIncident, currentParticle, targetParticle,
|
|
incidentHasChanged, targetHasChanged, quasiElastic );
|
|
|
|
CalculateMomenta( vec, vecLen,
|
|
originalIncident, originalTarget, modifiedOriginal,
|
|
targetNucleus, currentParticle, targetParticle,
|
|
incidentHasChanged, targetHasChanged, quasiElastic );
|
|
|
|
SetUpChange( vec, vecLen,
|
|
currentParticle, targetParticle,
|
|
incidentHasChanged );
|
|
|
|
delete originalTarget;
|
|
|
|
return &theParticleChange;
|
|
}
|
|
|
|
|
|
void G4RPGKPlusInelastic::Cascade(
|
|
G4FastVector<G4ReactionProduct,GHADLISTSIZE> &vec,
|
|
G4int &vecLen,
|
|
const G4HadProjectile *originalIncident,
|
|
G4ReactionProduct ¤tParticle,
|
|
G4ReactionProduct &targetParticle,
|
|
G4bool &incidentHasChanged,
|
|
G4bool &targetHasChanged,
|
|
G4bool &quasiElastic )
|
|
{
|
|
// Derived from H. Fesefeldt's original FORTRAN code CASKP
|
|
//
|
|
// K+ undergoes interaction with nucleon within a nucleus. Check if it is
|
|
// energetically possible to produce pions/kaons. In not, assume nuclear excitation
|
|
// occurs and input particle is degraded in energy. No other particles are produced.
|
|
// If reaction is possible, find the correct number of pions/protons/neutrons
|
|
// produced using an interpolation to multiplicity data. Replace some pions or
|
|
// protons/neutrons by kaons or strange baryons according to the average
|
|
// multiplicity per Inelastic reaction.
|
|
//
|
|
const G4double mOriginal = originalIncident->GetDefinition()->GetPDGMass();
|
|
const G4double etOriginal = originalIncident->GetTotalEnergy();
|
|
const G4double targetMass = targetParticle.GetMass();
|
|
G4double centerofmassEnergy = std::sqrt( mOriginal*mOriginal +
|
|
targetMass*targetMass +
|
|
2.0*targetMass*etOriginal );
|
|
G4double availableEnergy = centerofmassEnergy-(targetMass+mOriginal);
|
|
if( availableEnergy < G4PionPlus::PionPlus()->GetPDGMass() )
|
|
{
|
|
quasiElastic = true;
|
|
return;
|
|
}
|
|
static G4ThreadLocal G4bool first = true;
|
|
const G4int numMul = 1200;
|
|
const G4int numSec = 60;
|
|
static G4ThreadLocal G4double protmul[numMul], protnorm[numSec]; // proton constants
|
|
static G4ThreadLocal G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
|
|
|
|
// np = number of pi+, nneg = number of pi-, nz = number of pi0
|
|
|
|
G4int nt=0, np=0, nneg=0, nz=0;
|
|
const G4double c = 1.25;
|
|
const G4double b[] = { 0.70, 0.70 };
|
|
if( first ) // compute normalization constants, this will only be Done once
|
|
{
|
|
first = false;
|
|
G4int i;
|
|
for( i=0; i<numMul; ++i )protmul[i] = 0.0;
|
|
for( i=0; i<numSec; ++i )protnorm[i] = 0.0;
|
|
G4int counter = -1;
|
|
for( np=0; np<(numSec/3); ++np )
|
|
{
|
|
for( nneg=std::max(0,np-2); nneg<=np; ++nneg )
|
|
{
|
|
for( nz=0; nz<numSec/3; ++nz )
|
|
{
|
|
if( ++counter < numMul )
|
|
{
|
|
nt = np+nneg+nz;
|
|
if( nt > 0 )
|
|
{
|
|
protmul[counter] = Pmltpc(np,nneg,nz,nt,b[0],c);
|
|
protnorm[nt-1] += protmul[counter];
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
for( i=0; i<numMul; ++i )neutmul[i] = 0.0;
|
|
for( i=0; i<numSec; ++i )neutnorm[i] = 0.0;
|
|
counter = -1;
|
|
for( np=0; np<numSec/3; ++np )
|
|
{
|
|
for( nneg=std::max(0,np-1); nneg<=(np+1); ++nneg )
|
|
{
|
|
for( nz=0; nz<numSec/3; ++nz )
|
|
{
|
|
if( ++counter < numMul )
|
|
{
|
|
nt = np+nneg+nz;
|
|
if( (nt>0) && (nt<=numSec) )
|
|
{
|
|
neutmul[counter] = Pmltpc(np,nneg,nz,nt,b[1],c);
|
|
neutnorm[nt-1] += neutmul[counter];
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
for( i=0; i<numSec; ++i )
|
|
{
|
|
if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
|
|
if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
|
|
}
|
|
} // end of initialization
|
|
|
|
const G4double expxu = 82.; // upper bound for arg. of exp
|
|
const G4double expxl = -expxu; // lower bound for arg. of exp
|
|
G4ParticleDefinition *aKaonZS = G4KaonZeroShort::KaonZeroShort();
|
|
G4ParticleDefinition *aKaonZL = G4KaonZeroLong::KaonZeroLong();
|
|
G4ParticleDefinition *aNeutron = G4Neutron::Neutron();
|
|
G4ParticleDefinition *aProton = G4Proton::Proton();
|
|
G4int ieab = static_cast<G4int>(availableEnergy*5.0/GeV);
|
|
const G4double supp[] = {0.,0.4,0.55,0.65,0.75,0.82,0.86,0.90,0.94,0.98};
|
|
G4double test, w0, wp, wt, wm;
|
|
if( (availableEnergy < 2.0*GeV) && (G4UniformRand() >= supp[ieab]) )
|
|
{
|
|
// suppress high multiplicity events at low momentum
|
|
// only one pion will be produced
|
|
|
|
nneg = np = nz = 0;
|
|
if( targetParticle.GetDefinition() == aProton )
|
|
{
|
|
test = G4Exp( std::min( expxu, std::max( expxl, -sqr(1.0+b[0])/(2.0*c*c) ) ) );
|
|
w0 = test;
|
|
wp = test*2.0;
|
|
if( G4UniformRand() < w0/(w0+wp) )
|
|
nz = 1;
|
|
else
|
|
np = 1;
|
|
}
|
|
else // target is a neutron
|
|
{
|
|
test = G4Exp( std::min( expxu, std::max( expxl, -sqr(1.0+b[1])/(2.0*c*c) ) ) );
|
|
w0 = test;
|
|
wp = test;
|
|
test = G4Exp( std::min( expxu, std::max( expxl, -sqr(-1.0+b[1])/(2.0*c*c) ) ) );
|
|
wm = test;
|
|
wt = w0+wp+wm;
|
|
wp += w0;
|
|
G4double ran = G4UniformRand();
|
|
if( ran < w0/wt )
|
|
nz = 1;
|
|
else if( ran < wp/wt )
|
|
np = 1;
|
|
else
|
|
nneg = 1;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
G4double n, anpn;
|
|
GetNormalizationConstant( availableEnergy, n, anpn );
|
|
G4double ran = G4UniformRand();
|
|
G4double dum, excs = 0.0;
|
|
if( targetParticle.GetDefinition() == aProton )
|
|
{
|
|
G4int counter = -1;
|
|
for( np=0; (np<numSec/3) && (ran>=excs); ++np )
|
|
{
|
|
for( nneg=std::max(0,np-2); (nneg<=np) && (ran>=excs); ++nneg )
|
|
{
|
|
for( nz=0; (nz<numSec/3) && (ran>=excs); ++nz )
|
|
{
|
|
if( ++counter < numMul )
|
|
{
|
|
nt = np+nneg+nz;
|
|
if( nt > 0 )
|
|
{
|
|
test = G4Exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
|
|
dum = (pi/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
|
|
if( std::fabs(dum) < 1.0 )
|
|
{
|
|
if( test >= 1.0e-10 )excs += dum*test;
|
|
}
|
|
else
|
|
excs += dum*test;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if( ran >= excs )return; // 3 previous loops continued to the end
|
|
np--; nneg--; nz--;
|
|
}
|
|
else // target must be a neutron
|
|
{
|
|
G4int counter = -1;
|
|
for( np=0; (np<numSec/3) && (ran>=excs); ++np )
|
|
{
|
|
for( nneg=std::max(0,np-1); (nneg<=(np+1)) && (ran>=excs); ++nneg )
|
|
{
|
|
for( nz=0; (nz<numSec/3) && (ran>=excs); ++nz )
|
|
{
|
|
if( ++counter < numMul )
|
|
{
|
|
nt = np+nneg+nz;
|
|
if( (nt>=1) && (nt<=numSec) )
|
|
{
|
|
test = G4Exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(nt*nt)/(n*n) ) ) );
|
|
dum = (pi/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
|
|
if( std::fabs(dum) < 1.0 )
|
|
{
|
|
if( test >= 1.0e-10 )excs += dum*test;
|
|
}
|
|
else
|
|
excs += dum*test;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if( ran >= excs )return; // 3 previous loops continued to the end
|
|
np--; nneg--; nz--;
|
|
}
|
|
}
|
|
|
|
if( targetParticle.GetDefinition() == aProton )
|
|
{
|
|
switch( np-nneg )
|
|
{
|
|
case 1:
|
|
if( G4UniformRand() < 0.5 )
|
|
{
|
|
if( G4UniformRand() < 0.5 )
|
|
currentParticle.SetDefinitionAndUpdateE( aKaonZS );
|
|
else
|
|
currentParticle.SetDefinitionAndUpdateE( aKaonZL );
|
|
incidentHasChanged = true;
|
|
}
|
|
else
|
|
{
|
|
targetParticle.SetDefinitionAndUpdateE( aNeutron );
|
|
targetHasChanged = true;
|
|
}
|
|
break;
|
|
case 2:
|
|
if( G4UniformRand() < 0.5 )
|
|
currentParticle.SetDefinitionAndUpdateE( aKaonZS );
|
|
else
|
|
currentParticle.SetDefinitionAndUpdateE( aKaonZL );
|
|
incidentHasChanged = true;
|
|
targetParticle.SetDefinitionAndUpdateE( aNeutron );
|
|
incidentHasChanged = true;
|
|
targetHasChanged = true;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
else // target is a neutron
|
|
{
|
|
switch( np-nneg )
|
|
{
|
|
case 0:
|
|
if( G4UniformRand() < 0.25 )
|
|
{
|
|
if( G4UniformRand() < 0.5 )
|
|
currentParticle.SetDefinitionAndUpdateE( aKaonZS );
|
|
else
|
|
currentParticle.SetDefinitionAndUpdateE( aKaonZL );
|
|
targetParticle.SetDefinitionAndUpdateE( aProton );
|
|
incidentHasChanged = true;
|
|
targetHasChanged = true;
|
|
}
|
|
break;
|
|
case 1:
|
|
if( G4UniformRand() < 0.5 )
|
|
currentParticle.SetDefinitionAndUpdateE( aKaonZS );
|
|
else
|
|
currentParticle.SetDefinitionAndUpdateE( aKaonZL );
|
|
incidentHasChanged = true;
|
|
break;
|
|
default: // assumes nneg = np+1 so charge is conserved
|
|
targetParticle.SetDefinitionAndUpdateE( aProton );
|
|
targetHasChanged = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
SetUpPions(np, nneg, nz, vec, vecLen);
|
|
return;
|
|
}
|
|
|
|
/* end of file */
|
|
|