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geant4/source/processes/hadronic/models/coherent_elastic/src/G4LEpp.cc
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Gabriele Cosmo d4af681f38 Import Geant4 10.2.0 source tree
2016-06-10 14:11:04 +02:00

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//
// ********************************************************************
// * 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. *
// ********************************************************************
//
// G4 Low energy model: n-n or p-p scattering
// F.W. Jones, L.G. Greeniaus, H.P. Wellisch
// FWJ 27-AUG-2010: extended Coulomb-suppressed data to 5 GeV
#include "G4LEpp.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "Randomize.hh"
#include "G4ios.hh"
// Initialization of static data arrays:
#include "G4LEppData.hh"
G4LEpp::G4LEpp():G4HadronElastic("G4LEpp")
{
SetMinEnergy(0.);
SetMaxEnergy(5.*GeV);
}
G4LEpp::~G4LEpp()
{}
G4HadFinalState*
G4LEpp::ApplyYourself(const G4HadProjectile& aTrack, G4Nucleus& targetNucleus)
{
theParticleChange.Clear();
const G4HadProjectile* aParticle = &aTrack;
G4double P = aParticle->GetTotalMomentum();
G4double Px = aParticle->Get4Momentum().x();
G4double Py = aParticle->Get4Momentum().y();
G4double Pz = aParticle->Get4Momentum().z();
G4double E = aParticle->GetTotalEnergy();
G4ThreeVector theInitial = aParticle->Get4Momentum().vect().unit();
if (verboseLevel > 1) {
G4double ek = aParticle->GetKineticEnergy();
G4double E0 = aParticle->GetDefinition()->GetPDGMass();
G4double Q = aParticle->GetDefinition()->GetPDGCharge();
G4int A = targetNucleus.GetA_asInt();
G4int Z = targetNucleus.GetZ_asInt();
G4cout << "G4LEpp:ApplyYourself: incident particle: "
<< aParticle->GetDefinition()->GetParticleName() << G4endl;
G4cout << "P = " << P/GeV << " GeV/c"
<< ", Px = " << Px/GeV << " GeV/c"
<< ", Py = " << Py/GeV << " GeV/c"
<< ", Pz = " << Pz/GeV << " GeV/c" << G4endl;
G4cout << "E = " << E/GeV << " GeV"
<< ", kinetic energy = " << ek/GeV << " GeV"
<< ", mass = " << E0/GeV << " GeV"
<< ", charge = " << Q << G4endl;
G4cout << "G4LEpp:ApplyYourself: material:" << G4endl;
G4cout << "A = " << A
<< ", Z = " << Z
<< ", atomic mass "
<< G4Proton::Proton()->GetPDGMass()/GeV << "GeV"
<< G4endl;
//
// GHEISHA ADD operation to get total energy, mass, charge
//
E += proton_mass_c2;
G4double E02 = E*E - P*P;
E0 = std::sqrt(std::fabs(E02));
if (E02 < 0)E0 *= -1;
Q += Z;
G4cout << "G4LEpp:ApplyYourself: total:" << G4endl;
G4cout << "E = " << E/GeV << " GeV"
<< ", mass = " << E0/GeV << " GeV"
<< ", charge = " << Q << G4endl;
}
G4double t = SampleInvariantT(aParticle->GetDefinition(), P, 0, 0);
G4double cost = 1.0 - 2*t/(P*P);
if(cost > 1.0) { cost = 1.0; }
if(cost <-1.0) { cost =-1.0; }
G4double sint = std::sqrt((1.0 - cost)*(1.0 + cost));
G4double phi = twopi*G4UniformRand();
// Get the target particle
G4DynamicParticle* targetParticle = targetNucleus.ReturnTargetParticle();
G4double E1 = aParticle->GetTotalEnergy();
G4double M1 = aParticle->GetDefinition()->GetPDGMass();
G4double E2 = targetParticle->GetTotalEnergy();
G4double M2 = targetParticle->GetDefinition()->GetPDGMass();
G4double totalEnergy = E1 + E2;
G4double pseudoMass = std::sqrt(totalEnergy*totalEnergy - P*P);
// Transform into centre of mass system
G4double px = (M2/pseudoMass)*Px;
G4double py = (M2/pseudoMass)*Py;
G4double pz = (M2/pseudoMass)*Pz;
G4double p = std::sqrt(px*px + py*py + pz*pz);
if (verboseLevel > 1) {
G4cout << " E1, M1 (GeV) " << E1/GeV << " " << M1/GeV << G4endl;
G4cout << " E2, M2 (GeV) " << E2/GeV << " " << M2/GeV << G4endl;
G4cout << " particle 1 momentum in CM " << px/GeV
<< " " << py/GeV << " "
<< pz/GeV << " " << p/GeV << G4endl;
}
// First scatter w.r.t. Z axis
G4double pxnew = p*sint*std::cos(phi);
G4double pynew = p*sint*std::sin(phi);
G4double pznew = p*cost;
// Rotate according to the direction of the incident particle
if (px*px + py*py > 0) {
G4double ph, cosp, sinp;
cost = pz/p;
sint = (std::sqrt((1-cost)*(1+cost)) + std::sqrt(px*px+py*py)/p)/2;
py < 0 ? ph = 3*halfpi : ph = halfpi;
if (std::fabs(px) > 0.000001*GeV) ph = std::atan2(py,px);
cosp = std::cos(ph);
sinp = std::sin(ph);
px = (cost*cosp*pxnew - sinp*pynew + sint*cosp*pznew);
py = (cost*sinp*pxnew + cosp*pynew + sint*sinp*pznew);
pz = (-sint*pxnew + cost*pznew);
}
else {
px = pxnew;
py = pynew;
pz = pznew;
}
if (verboseLevel > 1) {
G4cout << " AFTER SCATTER..." << G4endl;
G4cout << " particle 1 momentum in CM " << px/GeV << " " << py/GeV << " "
<< pz/GeV << " " << p/GeV << G4endl;
}
// Transform to lab system
G4double E1pM2 = E1 + M2;
G4double betaCM = P/E1pM2;
G4double betaCMx = Px/E1pM2;
G4double betaCMy = Py/E1pM2;
G4double betaCMz = Pz/E1pM2;
G4double gammaCM = E1pM2/std::sqrt(E1pM2*E1pM2 - P*P);
if (verboseLevel > 1) {
G4cout << " betaCM " << betaCMx << " " << betaCMy << " "
<< betaCMz << " " << betaCM << G4endl;
G4cout << " gammaCM " << gammaCM << G4endl;
}
// Now following GLOREN...
G4double BETA[5], PA[5], PB[5];
BETA[1] = -betaCMx;
BETA[2] = -betaCMy;
BETA[3] = -betaCMz;
BETA[4] = gammaCM;
//The incident particle...
PA[1] = px;
PA[2] = py;
PA[3] = pz;
PA[4] = std::sqrt(M1*M1 + p*p);
G4double BETPA = BETA[1]*PA[1] + BETA[2]*PA[2] + BETA[3]*PA[3];
G4double BPGAM = (BETPA * BETA[4]/(BETA[4] + 1.) - PA[4]) * BETA[4];
PB[1] = PA[1] + BPGAM * BETA[1];
PB[2] = PA[2] + BPGAM * BETA[2];
PB[3] = PA[3] + BPGAM * BETA[3];
PB[4] = (PA[4] - BETPA) * BETA[4];
G4DynamicParticle* newP = new G4DynamicParticle;
newP->SetDefinition(aParticle->GetDefinition());
newP->SetMomentum(G4ThreeVector(PB[1], PB[2], PB[3]));
//The target particle...
PA[1] = -px;
PA[2] = -py;
PA[3] = -pz;
PA[4] = std::sqrt(M2*M2 + p*p);
BETPA = BETA[1]*PA[1] + BETA[2]*PA[2] + BETA[3]*PA[3];
BPGAM = (BETPA * BETA[4]/(BETA[4] + 1.) - PA[4]) * BETA[4];
PB[1] = PA[1] + BPGAM * BETA[1];
PB[2] = PA[2] + BPGAM * BETA[2];
PB[3] = PA[3] + BPGAM * BETA[3];
PB[4] = (PA[4] - BETPA) * BETA[4];
targetParticle->SetMomentum(G4ThreeVector(PB[1], PB[2], PB[3]));
if (verboseLevel > 1) {
G4cout << " particle 1 momentum in LAB "
<< newP->GetMomentum()/GeV
<< " " << newP->GetTotalMomentum()/GeV << G4endl;
G4cout << " particle 2 momentum in LAB "
<< targetParticle->GetMomentum()/GeV
<< " " << targetParticle->GetTotalMomentum()/GeV << G4endl;
G4cout << " TOTAL momentum in LAB "
<< (newP->GetMomentum()+targetParticle->GetMomentum())/GeV
<< " "
<< (newP->GetMomentum()+targetParticle->GetMomentum()).mag()/GeV
<< G4endl;
}
theParticleChange.SetMomentumChange( newP->GetMomentumDirection());
theParticleChange.SetEnergyChange(newP->GetKineticEnergy());
delete newP;
// Recoil particle
theParticleChange.AddSecondary(targetParticle);
return &theParticleChange;
}
////////////////////////////////////////////////////////////////////
//
// sample momentum transfer using Lab. momentum
G4double G4LEpp::SampleInvariantT(const G4ParticleDefinition* p,
G4double plab, G4int , G4int )
{
G4double nMass = p->GetPDGMass(); // 939.565346*MeV;
G4double ek = std::sqrt(plab*plab+nMass*nMass) - nMass;
// Find energy bin
G4int je1 = 0;
G4int je2 = NENERGY - 1;
ek /= GeV;
do
{
G4int midBin = (je1 + je2)/2;
if (ek < elab[midBin]) je2 = midBin;
else je1 = midBin;
}
while (je2 - je1 > 1); /* Loop checking, 10.08.2015, A.Ribon */
G4double delab = elab[je2] - elab[je1];
// Sample the angle
G4double sample = G4UniformRand();
G4int ke1 = 0;
G4int ke2 = NANGLE - 1;
G4double dsig, b, rc;
dsig = Sig[je2][0] - Sig[je1][0];
rc = dsig/delab;
b = Sig[je1][0] - rc*elab[je1];
G4double sigint1 = rc*ek + b;
G4double sigint2 = 0.;
do
{
G4int midBin = (ke1 + ke2)/2;
dsig = Sig[je2][midBin] - Sig[je1][midBin];
rc = dsig/delab;
b = Sig[je1][midBin] - rc*elab[je1];
G4double sigint = rc*ek + b;
if (sample < sigint)
{
ke2 = midBin;
sigint2 = sigint;
}
else
{
ke1 = midBin;
sigint1 = sigint;
}
}
while (ke2 - ke1 > 1); /* Loop checking, 10.08.2015, A.Ribon */
dsig = sigint2 - sigint1;
rc = 1./dsig;
b = ke1 - rc*sigint1;
G4double kint = rc*sample + b;
G4double theta = (0.5 + kint)*pi/180.;
G4double t = 0.5*plab*plab*(1 - std::cos(theta));
return t;
}
// end of file
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