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geant4/source/processes/hadronic/util/src/G4Nucleus.cc
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//
//
//
// original by H.P. Wellisch
// modified by J.L. Chuma, TRIUMF, 19-Nov-1996
// last modified: 27-Mar-1997
// J.P.Wellisch: 23-Apr-97: minor simplifications
// modified by J.L.Chuma 24-Jul-97 to set the total momentum in Cinema and
// EvaporationEffects
// modified by J.L.Chuma 21-Oct-97 put std::abs() around the totalE^2-mass^2
// in calculation of total momentum in
// Cinema and EvaporationEffects
// Chr. Volcker, 10-Nov-1997: new methods and class variables.
// HPW added utilities for low energy neutron transport. (12.04.1998)
// M.G. Pia, 2 Oct 1998: modified GetFermiMomentum to avoid memory leaks
// G.Folger, spring 2010: add integer A/Z interface
// A. Ribon, summer 2015: migrated to G4Exp and G4Log
// A. Ribon, autumn 2021: extended to hypernuclei
#include "G4Nucleus.hh"
#include "G4NucleiProperties.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "Randomize.hh"
#include "G4HadronicException.hh"
#include "G4Exp.hh"
#include "G4Log.hh"
#include "G4HyperNucleiProperties.hh"
#include "G4HadronicParameters.hh"
G4Nucleus::G4Nucleus()
: theA(0), theZ(0), theL(0), aEff(0.0), zEff(0)
{
pnBlackTrackEnergy = 0.0;
dtaBlackTrackEnergy = 0.0;
pnBlackTrackEnergyfromAnnihilation = 0.0;
dtaBlackTrackEnergyfromAnnihilation = 0.0;
excitationEnergy = 0.0;
momentum = G4ThreeVector(0.,0.,0.);
fermiMomentum = 1.52*hbarc/fermi;
theTemp = 293.16*kelvin;
fIsotope = 0;
}
G4Nucleus::G4Nucleus( const G4double A, const G4double Z, const G4int numberOfLambdas )
{
SetParameters( A, Z, std::max(numberOfLambdas, 0) );
pnBlackTrackEnergy = 0.0;
dtaBlackTrackEnergy = 0.0;
pnBlackTrackEnergyfromAnnihilation = 0.0;
dtaBlackTrackEnergyfromAnnihilation = 0.0;
excitationEnergy = 0.0;
momentum = G4ThreeVector(0.,0.,0.);
fermiMomentum = 1.52*hbarc/fermi;
theTemp = 293.16*kelvin;
fIsotope = 0;
}
G4Nucleus::G4Nucleus( const G4int A, const G4int Z, const G4int numberOfLambdas )
{
SetParameters( A, Z, std::max(numberOfLambdas, 0) );
pnBlackTrackEnergy = 0.0;
dtaBlackTrackEnergy = 0.0;
pnBlackTrackEnergyfromAnnihilation = 0.0;
dtaBlackTrackEnergyfromAnnihilation = 0.0;
excitationEnergy = 0.0;
momentum = G4ThreeVector(0.,0.,0.);
fermiMomentum = 1.52*hbarc/fermi;
theTemp = 293.16*kelvin;
fIsotope = 0;
}
G4Nucleus::G4Nucleus( const G4Material *aMaterial )
{
ChooseParameters( aMaterial );
pnBlackTrackEnergy = 0.0;
dtaBlackTrackEnergy = 0.0;
pnBlackTrackEnergyfromAnnihilation = 0.0;
dtaBlackTrackEnergyfromAnnihilation = 0.0;
excitationEnergy = 0.0;
momentum = G4ThreeVector(0.,0.,0.);
fermiMomentum = 1.52*hbarc/fermi;
theTemp = aMaterial->GetTemperature();
fIsotope = 0;
}
G4Nucleus::~G4Nucleus() {}
//-------------------------------------------------------------------------------------------------
// SVT (Sampling of the Velocity of the Target nucleus) method, L. Thulliez (CEA-Saclay) 2021/05/04
//-------------------------------------------------------------------------------------------------
G4ReactionProduct
G4Nucleus::GetBiasedThermalNucleus(G4double aMass, G4ThreeVector aVelocity, G4double temp) const
{
// If E_neutron <= E_threshold, Then apply the Sampling ot the Velocity of the Target (SVT) method;
// Else consider the target nucleus being without motion.
G4double E_threshold = G4HadronicParameters::Instance()->GetNeutronKineticEnergyThresholdForSVT();
if ( E_threshold == -1. ) {
E_threshold = 400.0*8.617333262E-11*temp;
}
G4double E_neutron = 0.5*aVelocity.mag2()*G4Neutron::Neutron()->GetPDGMass(); // E=0.5*m*v2
G4ReactionProduct result;
result.SetMass(aMass*G4Neutron::Neutron()->GetPDGMass());
if ( E_neutron <= E_threshold ) {
// Beta = sqrt(m/2kT)
G4double beta = std::sqrt(result.GetMass()/(2.*8.617333262E-11*temp)); // kT E-5[eV] mass E-11[MeV] => beta in [m/s]-1
// Neutron speed vn
G4double vN_norm = aVelocity.mag();
G4double vN_norm2 = vN_norm*vN_norm;
G4double y = beta*vN_norm;
// Normalize neutron velocity
aVelocity = (1./vN_norm)*aVelocity;
// Sample target speed
G4double x2;
G4double randThreshold;
G4double vT_norm, vT_norm2, mu; //theta, val1, val2,
G4double acceptThreshold;
G4double vRelativeSpeed;
G4double cdf0 = 2./(2.+std::sqrt(CLHEP::pi)*y);
do {
// Sample the target velocity vT in the laboratory frame
if ( G4UniformRand() < cdf0 ) {
// Sample in C45 from https://laws.lanl.gov/vhosts/mcnp.lanl.gov/pdf_files/la-9721.pdf
x2 = -std::log(G4UniformRand()*G4UniformRand());
} else {
// Sample in C61 from https://laws.lanl.gov/vhosts/mcnp.lanl.gov/pdf_files/la-9721.pdf
G4double ampl = std::cos(CLHEP::pi/2.0 * G4UniformRand());
x2 = -std::log(G4UniformRand()) - std::log(G4UniformRand())*ampl*ampl;
}
vT_norm = std::sqrt(x2)/beta;
vT_norm2 = vT_norm*vT_norm;
// Sample cosine between the incident neutron and the target in the laboratory frame
mu = 2*G4UniformRand() - 1;
// Define acceptance threshold
vRelativeSpeed = std::sqrt(vN_norm2 + vT_norm2 - 2*vN_norm*vT_norm*mu);
acceptThreshold = vRelativeSpeed/(vN_norm + vT_norm);
randThreshold = G4UniformRand();
} while ( randThreshold >= acceptThreshold );
DoKinematicsOfThermalNucleus(mu, vT_norm, aVelocity, result);
} else { // target nucleus considered as being without motion
result.SetMomentum(0., 0., 0.);
result.SetKineticEnergy(0.);
}
return result;
}
void
G4Nucleus::DoKinematicsOfThermalNucleus(const G4double mu, const G4double vT_norm, const G4ThreeVector& aVelocity,
G4ReactionProduct& result) const {
// Get target nucleus direction from the neutron direction and the relative angle between target nucleus and neutron (mu)
G4double cosTh = mu;
G4ThreeVector uNorm = aVelocity;
G4double sinTh = std::sqrt(1. - cosTh*cosTh);
// Sample randomly the phi angle between the neutron veloicty and the target velocity
G4double phi = CLHEP::twopi*G4UniformRand();
G4double sinPhi = std::sin(phi);
G4double cosPhi = std::cos(phi);
// Find orthogonal vector to aVelocity - solve equation xx' + yy' + zz' = 0
G4ThreeVector ortho(1., 1., 1.);
if ( uNorm[0] ) ortho[0] = -(uNorm[1]+uNorm[2])/uNorm[0];
else if ( uNorm[1] ) ortho[1] = -(uNorm[0]+uNorm[2])/uNorm[1];
else if ( uNorm[2] ) ortho[2] = -(uNorm[0]+uNorm[1])/uNorm[2];
// Normalize the vector
ortho = (1/ortho.mag())*ortho;
// Find vector to draw a plan perpendicular to uNorm (i.e neutron velocity) with vectors ortho & orthoComp
G4ThreeVector orthoComp( uNorm[1]*ortho[2] - ortho[1]*uNorm[2],
uNorm[2]*ortho[0] - ortho[2]*uNorm[0],
uNorm[0]*ortho[1] - ortho[0]*uNorm[1] );
// Find the direction of the target velocity in the laboratory frame
G4ThreeVector directionTarget( cosTh*uNorm[0] + sinTh*(cosPhi*orthoComp[0] + sinPhi*ortho[0]),
cosTh*uNorm[1] + sinTh*(cosPhi*orthoComp[1] + sinPhi*ortho[1]),
cosTh*uNorm[2] + sinTh*(cosPhi*orthoComp[2] + sinPhi*ortho[2]) );
// Normalize directionTarget
directionTarget = ( 1./directionTarget.mag() )*directionTarget;
// Set momentum
G4double px = result.GetMass()*vT_norm*directionTarget[0];
G4double py = result.GetMass()*vT_norm*directionTarget[1];
G4double pz = result.GetMass()*vT_norm*directionTarget[2];
result.SetMomentum(px, py, pz);
G4double tMom = std::sqrt(px*px+py*py+pz*pz);
G4double tEtot = std::sqrt( (tMom+result.GetMass())*(tMom+result.GetMass())
- 2.*tMom*result.GetMass() );
if ( tEtot/result.GetMass() - 1. > 0.001 ) {
// use relativistic energy for higher energies
result.SetTotalEnergy(tEtot);
} else {
// use p**2/2M for lower energies (to preserve precision?)
result.SetKineticEnergy(tMom*tMom/(2.*result.GetMass()));
}
}
G4ReactionProduct
G4Nucleus::GetThermalNucleus(G4double targetMass, G4double temp) const
{
G4double currentTemp = temp;
if (currentTemp < 0) currentTemp = theTemp;
G4ReactionProduct theTarget;
theTarget.SetMass(targetMass*G4Neutron::Neutron()->GetPDGMass());
G4double px, py, pz;
px = GetThermalPz(theTarget.GetMass(), currentTemp);
py = GetThermalPz(theTarget.GetMass(), currentTemp);
pz = GetThermalPz(theTarget.GetMass(), currentTemp);
theTarget.SetMomentum(px, py, pz);
G4double tMom = std::sqrt(px*px+py*py+pz*pz);
G4double tEtot = std::sqrt((tMom+theTarget.GetMass())*
(tMom+theTarget.GetMass())-
2.*tMom*theTarget.GetMass());
// if(1-tEtot/theTarget.GetMass()>0.001) this line incorrect (Bug report 1911)
if (tEtot/theTarget.GetMass() - 1. > 0.001) {
// use relativistic energy for higher energies
theTarget.SetTotalEnergy(tEtot);
} else {
// use p**2/2M for lower energies (to preserve precision?)
theTarget.SetKineticEnergy(tMom*tMom/(2.*theTarget.GetMass()));
}
return theTarget;
}
void
G4Nucleus::ChooseParameters(const G4Material* aMaterial)
{
G4double random = G4UniformRand();
G4double sum = aMaterial->GetTotNbOfAtomsPerVolume();
const G4ElementVector* theElementVector = aMaterial->GetElementVector();
G4double running(0);
// G4Element* element(0);
const G4Element* element = (*theElementVector)[aMaterial->GetNumberOfElements()-1];
for (unsigned int i = 0; i < aMaterial->GetNumberOfElements(); ++i) {
running += aMaterial->GetVecNbOfAtomsPerVolume()[i];
if (running > random*sum) {
element = (*theElementVector)[i];
break;
}
}
if (element->GetNumberOfIsotopes() > 0) {
G4double randomAbundance = G4UniformRand();
G4double sumAbundance = element->GetRelativeAbundanceVector()[0];
unsigned int iso=0;
while (iso < element->GetNumberOfIsotopes() && /* Loop checking, 02.11.2015, A.Ribon */
sumAbundance < randomAbundance) {
++iso;
sumAbundance += element->GetRelativeAbundanceVector()[iso];
}
theA=element->GetIsotope(iso)->GetN();
theZ=element->GetIsotope(iso)->GetZ();
theL=0;
aEff=theA;
zEff=theZ;
} else {
aEff = element->GetN();
zEff = element->GetZ();
theZ = G4int(zEff + 0.5);
theA = G4int(aEff + 0.5);
theL=0;
}
}
void
G4Nucleus::SetParameters( const G4double A, const G4double Z, const G4int numberOfLambdas )
{
theZ = G4lrint(Z);
theA = G4lrint(A);
theL = std::max(numberOfLambdas, 0);
if (theA<1 || theZ<0 || theZ>theA) {
throw G4HadronicException(__FILE__, __LINE__,
"G4Nucleus::SetParameters called with non-physical parameters");
}
aEff = A; // atomic weight
zEff = Z; // atomic number
fIsotope = 0;
}
void
G4Nucleus::SetParameters( const G4int A, const G4int Z, const G4int numberOfLambdas )
{
theZ = Z;
theA = A;
theL = std::max(numberOfLambdas, 0);
if( theA<1 || theZ<0 || theZ>theA )
{
throw G4HadronicException(__FILE__, __LINE__,
"G4Nucleus::SetParameters called with non-physical parameters");
}
aEff = A; // atomic weight
zEff = Z; // atomic number
fIsotope = 0;
}
G4DynamicParticle *
G4Nucleus::ReturnTargetParticle() const
{
// choose a proton or a neutron (or a lamba if a hypernucleus) as the target particle
G4DynamicParticle *targetParticle = new G4DynamicParticle;
const G4double rnd = G4UniformRand();
if ( rnd < zEff/aEff ) {
targetParticle->SetDefinition( G4Proton::Proton() );
} else if ( rnd < (zEff + theL*1.0)/aEff ) {
targetParticle->SetDefinition( G4Lambda::Lambda() );
} else {
targetParticle->SetDefinition( G4Neutron::Neutron() );
}
return targetParticle;
}
G4double
G4Nucleus::AtomicMass( const G4double A, const G4double Z, const G4int numberOfLambdas ) const
{
// Now returns (atomic mass - electron masses)
if ( numberOfLambdas > 0 ) {
return G4HyperNucleiProperties::GetNuclearMass(G4int(A), G4int(Z), numberOfLambdas);
} else {
return G4NucleiProperties::GetNuclearMass(A, Z);
}
}
G4double
G4Nucleus::AtomicMass( const G4int A, const G4int Z, const G4int numberOfLambdas ) const
{
// Now returns (atomic mass - electron masses)
if ( numberOfLambdas > 0 ) {
return G4HyperNucleiProperties::GetNuclearMass(A, Z, numberOfLambdas);
} else {
return G4NucleiProperties::GetNuclearMass(A, Z);
}
}
G4double
G4Nucleus::GetThermalPz( const G4double mass, const G4double temp ) const
{
G4double result = G4RandGauss::shoot();
result *= std::sqrt(k_Boltzmann*temp*mass); // Das ist impuls (Pz),
// nichtrelativistische rechnung
// Maxwell verteilung angenommen
return result;
}
G4double
G4Nucleus::EvaporationEffects( G4double kineticEnergy )
{
// derived from original FORTRAN code EXNU by H. Fesefeldt (10-Dec-1986)
//
// Nuclear evaporation as function of atomic number
// and kinetic energy (MeV) of primary particle
//
// returns kinetic energy (MeV)
//
if( aEff < 1.5 )
{
pnBlackTrackEnergy = dtaBlackTrackEnergy = 0.0;
return 0.0;
}
G4double ek = kineticEnergy/GeV;
G4float ekin = std::min( 4.0, std::max( 0.1, ek ) );
const G4float atno = std::min( 120., aEff );
const G4float gfa = 2.0*((aEff-1.0)/70.)*G4Exp(-(aEff-1.0)/70.);
//
// 0.35 value at 1 GeV
// 0.05 value at 0.1 GeV
//
G4float cfa = std::max( 0.15, 0.35 + ((0.35-0.05)/2.3)*G4Log(ekin) );
G4float exnu = 7.716 * cfa * G4Exp(-cfa)
* ((atno-1.0)/120.)*G4Exp(-(atno-1.0)/120.);
G4float fpdiv = std::max( 0.5, 1.0-0.25*ekin*ekin );
//
// pnBlackTrackEnergy is the kinetic energy (in GeV) available for
// proton/neutron black track particles
// dtaBlackTrackEnergy is the kinetic energy (in GeV) available for
// deuteron/triton/alpha black track particles
//
pnBlackTrackEnergy = exnu*fpdiv;
dtaBlackTrackEnergy = exnu*(1.0-fpdiv);
if( G4int(zEff+0.1) != 82 )
{
G4double ran1 = -6.0;
G4double ran2 = -6.0;
for( G4int i=0; i<12; ++i )
{
ran1 += G4UniformRand();
ran2 += G4UniformRand();
}
pnBlackTrackEnergy *= 1.0 + ran1*gfa;
dtaBlackTrackEnergy *= 1.0 + ran2*gfa;
}
pnBlackTrackEnergy = std::max( 0.0, pnBlackTrackEnergy );
dtaBlackTrackEnergy = std::max( 0.0, dtaBlackTrackEnergy );
while( pnBlackTrackEnergy+dtaBlackTrackEnergy >= ek ) /* Loop checking, 02.11.2015, A.Ribon */
{
pnBlackTrackEnergy *= 1.0 - 0.5*G4UniformRand();
dtaBlackTrackEnergy *= 1.0 - 0.5*G4UniformRand();
}
//G4cout << "EvaporationEffects "<<kineticEnergy<<" "
// <<pnBlackTrackEnergy+dtaBlackTrackEnergy<< G4endl;
return (pnBlackTrackEnergy+dtaBlackTrackEnergy)*GeV;
}
G4double
G4Nucleus::AnnihilationEvaporationEffects(G4double kineticEnergy, G4double ekOrg)
{
// Nuclear evaporation as a function of atomic number and kinetic
// energy (MeV) of primary particle. Modified for annihilation effects.
//
if( aEff < 1.5 || ekOrg < 0.)
{
pnBlackTrackEnergyfromAnnihilation = 0.0;
dtaBlackTrackEnergyfromAnnihilation = 0.0;
return 0.0;
}
G4double ek = kineticEnergy/GeV;
G4float ekin = std::min( 4.0, std::max( 0.1, ek ) );
const G4float atno = std::min( 120., aEff );
const G4float gfa = 2.0*((aEff-1.0)/70.)*G4Exp(-(aEff-1.0)/70.);
G4float cfa = std::max( 0.15, 0.35 + ((0.35-0.05)/2.3)*G4Log(ekin) );
G4float exnu = 7.716 * cfa * G4Exp(-cfa)
* ((atno-1.0)/120.)*G4Exp(-(atno-1.0)/120.);
G4float fpdiv = std::max( 0.5, 1.0-0.25*ekin*ekin );
pnBlackTrackEnergyfromAnnihilation = exnu*fpdiv;
dtaBlackTrackEnergyfromAnnihilation = exnu*(1.0-fpdiv);
G4double ran1 = -6.0;
G4double ran2 = -6.0;
for( G4int i=0; i<12; ++i ) {
ran1 += G4UniformRand();
ran2 += G4UniformRand();
}
pnBlackTrackEnergyfromAnnihilation *= 1.0 + ran1*gfa;
dtaBlackTrackEnergyfromAnnihilation *= 1.0 + ran2*gfa;
pnBlackTrackEnergyfromAnnihilation = std::max( 0.0, pnBlackTrackEnergyfromAnnihilation);
dtaBlackTrackEnergyfromAnnihilation = std::max( 0.0, dtaBlackTrackEnergyfromAnnihilation);
G4double blackSum = pnBlackTrackEnergyfromAnnihilation+dtaBlackTrackEnergyfromAnnihilation;
if (blackSum >= ekOrg/GeV) {
pnBlackTrackEnergyfromAnnihilation *= ekOrg/GeV/blackSum;
dtaBlackTrackEnergyfromAnnihilation *= ekOrg/GeV/blackSum;
}
return (pnBlackTrackEnergyfromAnnihilation+dtaBlackTrackEnergyfromAnnihilation)*GeV;
}
G4double
G4Nucleus::Cinema( G4double kineticEnergy )
{
// derived from original FORTRAN code CINEMA by H. Fesefeldt (14-Oct-1987)
//
// input: kineticEnergy (MeV)
// returns modified kinetic energy (MeV)
//
static const G4double expxu = 82.; // upper bound for arg. of exp
static const G4double expxl = -expxu; // lower bound for arg. of exp
G4double ek = kineticEnergy/GeV;
G4double ekLog = G4Log( ek );
G4double aLog = G4Log( aEff );
G4double em = std::min( 1.0, 0.2390 + 0.0408*aLog*aLog );
G4double temp1 = -ek * std::min( 0.15, 0.0019*aLog*aLog*aLog );
G4double temp2 = G4Exp( std::max( expxl, std::min( expxu, -(ekLog-em)*(ekLog-em)*2.0 ) ) );
G4double result = 0.0;
if( std::abs( temp1 ) < 1.0 )
{
if( temp2 > 1.0e-10 )result = temp1*temp2;
}
else result = temp1*temp2;
if( result < -ek )result = -ek;
return result*GeV;
}
G4ThreeVector G4Nucleus::GetFermiMomentum()
{
// chv: .. we assume zero temperature!
// momentum is equally distributed in each phasespace volume dpx, dpy, dpz.
G4double ranflat1=
G4RandFlat::shoot((G4double)0.,(G4double)fermiMomentum);
G4double ranflat2=
G4RandFlat::shoot((G4double)0.,(G4double)fermiMomentum);
G4double ranflat3=
G4RandFlat::shoot((G4double)0.,(G4double)fermiMomentum);
G4double ranmax = (ranflat1>ranflat2? ranflat1: ranflat2);
ranmax = (ranmax>ranflat3? ranmax : ranflat3);
// Isotropic momentum distribution
G4double costheta = 2.*G4UniformRand() - 1.0;
G4double sintheta = std::sqrt(1.0 - costheta*costheta);
G4double phi = 2.0*pi*G4UniformRand();
G4double pz=costheta*ranmax;
G4double px=sintheta*std::cos(phi)*ranmax;
G4double py=sintheta*std::sin(phi)*ranmax;
G4ThreeVector p(px,py,pz);
return p;
}
G4ReactionProductVector* G4Nucleus::Fragmentate()
{
// needs implementation!
return nullptr;
}
void G4Nucleus::AddMomentum(const G4ThreeVector aMomentum)
{
momentum+=(aMomentum);
}
void G4Nucleus::AddExcitationEnergy( G4double anEnergy )
{
excitationEnergy+=anEnergy;
}
/* end of file */