G4NonEquilibriumEvaporator.cc

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// $Id$
//
// 20100114  M. Kelsey -- Remove G4CascadeMomentum, use G4LorentzVector directly
// 20100309  M. Kelsey -- Use new generateWithRandomAngles for theta,phi stuff;
//      eliminate some unnecessary std::pow()
// 20100412  M. Kelsey -- Pass G4CollisionOutput by ref to ::collide()
// 20100413  M. Kelsey -- Pass buffers to paraMaker[Truncated]
// 20100517  M. Kelsey -- Inherit from common base class
// 20100617  M. Kelsey -- Remove "RUN" preprocessor flag and all "#else" code
// 20100622  M. Kelsey -- Use local "bindingEnergy()" function to call through.
// 20100701  M. Kelsey -- Don't need to add excitation to nuclear mass; compute
//      new excitation energies properly (mass differences)
// 20100713  M. Kelsey -- Add conservation checking, diagnostic messages.
// 20100714  M. Kelsey -- Move conservation checking to base class
// 20100719  M. Kelsey -- Simplify EEXS calculations with particle evaporation.
// 20100724  M. Kelsey -- Replace std::vector<> D with trivial D[3] array.
// 20100914  M. Kelsey -- Migrate to integer A and Z: this involves replacing
//      a number of G4double terms with G4int, with consequent casts.
// 20110214  M. Kelsey -- Follow G4InuclParticle::Model enumerator migration
// 20110922  M. Kelsey -- Follow G4InuclParticle::print(ostream&) migration
// 20120608  M. Kelsey -- Fix variable-name "shadowing" compiler warnings.
// 20121009  M. Kelsey -- Add some high-verbosity debugging output
 
#include <cmath>
 
#include "G4NonEquilibriumEvaporator.hh"
#include "G4SystemOfUnits.hh"
#include "G4CollisionOutput.hh"
#include "G4InuclElementaryParticle.hh"
#include "G4InuclNuclei.hh"
#include "G4InuclSpecialFunctions.hh"
#include "G4LorentzConvertor.hh"
 
using namespace G4InuclSpecialFunctions;
 
 
G4NonEquilibriumEvaporator::G4NonEquilibriumEvaporator()
  : G4CascadeColliderBase("G4NonEquilibriumEvaporator") {}
 
 
void G4NonEquilibriumEvaporator::collide(G4InuclParticle* /*bullet*/,
                     G4InuclParticle* target,
                     G4CollisionOutput& output) {
 
  if (verboseLevel) {
    G4cout << " >>> G4NonEquilibriumEvaporator::collide" << G4endl;
  }
 
  // Sanity check
  G4InuclNuclei* nuclei_target = dynamic_cast<G4InuclNuclei*>(target);
  if (!nuclei_target) {
    G4cerr << " NonEquilibriumEvaporator -> target is not nuclei " << G4endl;    
    return;
  }
 
  if (verboseLevel > 2) G4cout << " evaporating target:\n" << *target << G4endl;
  
  const G4int a_cut = 5;
  const G4int z_cut = 3;
 
  const G4double eexs_cut = 0.1;
 
  const G4double coul_coeff = 1.4;
  const G4int itry_max = 1000;
  const G4double small_ekin = 1.0e-6;
  const G4double width_cut = 0.005;
 
  G4int A = nuclei_target->getA();
  G4int Z = nuclei_target->getZ();
  
  G4LorentzVector PEX = nuclei_target->getMomentum();
  G4LorentzVector pin = PEX;        // Save original four-vector for later
  
  G4double EEXS = nuclei_target->getExitationEnergy();
  
  G4ExitonConfiguration config = nuclei_target->getExitonConfiguration();  
 
  G4int QPP = config.protonQuasiParticles;
  G4int QNP = config.neutronQuasiParticles; 
  G4int QPH = config.protonHoles;
  G4int QNH = config.neutronHoles; 
  
  G4int QP = QPP + QNP;
  G4int QH = QPH + QNH;
  G4int QEX = QP + QH;
  
  G4InuclElementaryParticle dummy(small_ekin, 1);
  G4LorentzConvertor toTheExitonSystemRestFrame;
  //*** toTheExitonSystemRestFrame.setVerbose(verboseLevel);
  toTheExitonSystemRestFrame.setBullet(dummy);
  
  G4double EFN = FermiEnergy(A, Z, 0);
  G4double EFP = FermiEnergy(A, Z, 1);
  
  G4int AR = A - QP;
  G4int ZR = Z - QPP;  
  G4int NEX = QEX;
  G4LorentzVector ppout;
  G4bool try_again = (NEX > 0);
  
  // Buffer for parameter sets
  std::pair<G4double, G4double> parms;
  
  while (try_again) {
    if (A >= a_cut && Z >= z_cut && EEXS > eexs_cut) { // ok
      // update exiton system (include excitation energy!)
      G4double nuc_mass = G4InuclNuclei::getNucleiMass(A, Z, EEXS); 
      PEX.setVectM(PEX.vect(), nuc_mass);
      toTheExitonSystemRestFrame.setTarget(PEX);
      toTheExitonSystemRestFrame.toTheTargetRestFrame();
      
      if (verboseLevel > 2) {
    G4cout << " A " << A << " Z " << Z << " mass " << nuc_mass
           << " EEXS " << EEXS << G4endl; 
      }
      
      G4double MEL = getMatrixElement(A);
      G4double E0 = getE0(A);
      G4double PL = getParLev(A, Z);
      G4double parlev = PL / A;
      G4double EG = PL * EEXS;
      
      if (QEX < std::sqrt(2.0 * EG)) { // ok
    if (verboseLevel > 3)
      G4cout << " QEX " << QEX << " < sqrt(2*EG) " << std::sqrt(2.*EG)
         << " NEX " << NEX << G4endl;
    
    paraMakerTruncated(Z, parms);
    const G4double& AK1 = parms.first;
    const G4double& CPA1 = parms.second;
    
    G4double VP = coul_coeff * Z * AK1 / (G4cbrt(A-1) + 1.0) /
      (1.0 + EEXS / E0);
    G4double DM1 = bindingEnergy(A,Z);
    G4double BN = DM1 - bindingEnergy(A-1,Z);
    G4double BP = DM1 - bindingEnergy(A-1,Z-1);
    G4double EMN = EEXS - BN;
    G4double EMP = EEXS - BP - VP * A / (A-1);
    G4double ESP = 0.0;
 
    if (verboseLevel > 3) {
      G4cout << " AK1 " << AK1 << " CPA1 " << " VP " << VP
         << "\n bind(A,Z) " << DM1 << " dBind(N) " << BN 
         << " dBind(P) " << BP
         << "\n EMN " << EMN << " EMP " << EMP << G4endl;
    }
 
    if (EMN > eexs_cut) { // ok
      G4int icase = 0;
      
      if (NEX > 1) {
        G4double APH = 0.25 * (QP * QP + QH * QH + QP - 3 * QH);
        G4double APH1 = APH + 0.5 * (QP + QH);
        ESP = EEXS / QEX;
        G4double MELE = MEL / ESP / (A*A*A);
 
        if (verboseLevel > 3)
          G4cout << " APH " << APH << " APH1 " << APH1 << " ESP " << ESP
             << G4endl;
 
        if (ESP > 15.0) {
          MELE *= std::sqrt(15.0 / ESP);
        } else if(ESP < 7.0) {
          MELE *= std::sqrt(ESP / 7.0);
          if (ESP < 2.0) MELE *= std::sqrt(ESP / 2.0);
        };    
 
        G4double F1 = EG - APH;
        G4double F2 = EG - APH1;
 
        if (verboseLevel > 3)
          G4cout << " MELE " << MELE << " F1 " << F1 << " F2 " << F2
             << G4endl;
        
        if (F1 > 0.0 && F2 > 0.0) {
          G4double F = F2 / F1;
          G4double M1 = 2.77 * MELE * PL;
          G4double D[3] = { 0., 0., 0. };
          D[0] = M1 * F2 * F2 * std::pow(F, NEX-1) / (QEX+1);
          
          if (D[0] > 0.0) {
        
        if (NEX >= 2) {
          D[1] = 0.0462 / parlev / G4cbrt(A) * QP * EEXS / QEX;
          
          if (EMP > eexs_cut) 
            D[2] = D[1] * std::pow(EMP / EEXS, NEX) * (1.0 + CPA1);
          D[1] *= std::pow(EMN / EEXS, NEX) * getAL(A);   
          
          if (QNP < 1) D[1] = 0.0;
          if (QPP < 1) D[2] = 0.0;
          
          try_again = NEX > 1 && (D[1] > width_cut * D[0] || 
                      D[2] > width_cut * D[0]);
          
          if (try_again) {
            G4double D5 = D[0] + D[1] + D[2];
            G4double SL = D5 * inuclRndm();
            G4double S1 = 0.;
 
            if (verboseLevel > 3)
              G4cout << " D5 " << D5 << " SL " << SL << G4endl;
 
            for (G4int i = 0; i < 3; i++) {
              S1 += D[i];   
              if (SL <= S1) {
            icase = i;
            break;
              }
            }
 
            if (verboseLevel > 3)
              G4cout << " got icase " << icase << G4endl;
          }             // if (try_again)
        }               // if (NEX >= 2)
          } else try_again = false;     // if (D[0] > 0)
        } else try_again = false;       // if (F1>0 && F2>0)
      }                 // if (NEX > 1)
      
      if (try_again) {
        if (icase > 0) {            // N -> N-1 with particle escape
          if (verboseLevel > 3)
        G4cout << " try_again icase " << icase << G4endl;
          
          G4double V = 0.0;
          G4int ptype = 0;
          G4double B = 0.0;
          
          if (A < 3.0) try_again = false;
          
          if (try_again) { 
        
        if (icase == 1) { // neutron escape
          if (verboseLevel > 3)
            G4cout << " trying neutron escape" << G4endl;
 
          if (QNP < 1) icase = 0;
          else {
            B = BN;
            V = 0.0;
            ptype = 2;        
          };    
        } else { // proton esape
          if (verboseLevel > 3)
            G4cout << " trying proton escape" << G4endl;
 
          if (QPP < 1) icase = 0;
          else {
            B = BP;
            V = VP;
            ptype = 1;
            
            if (Z-1 < 1) try_again = false;
          };   
        };
            
        if (try_again && icase != 0) {
          if (verboseLevel > 3)
            G4cout << " ptype " << ptype << " B " << B << " V " << V
               << G4endl;
 
          G4double EB = EEXS - B;
          G4double E = EB - V * A / (A-1);
          
          if (E < 0.0) icase = 0;
          else {
            G4double E1 = EB - V;
            G4double EEXS_new = -1.;
            G4double EPART = 0.0;
            G4int itry1 = 0;
            G4bool bad = true;
            
            while (itry1 < itry_max && icase > 0 && bad) {
              itry1++;
              G4int itry = 0;           
              
              while (EEXS_new < 0.0 && itry < itry_max) {
            itry++;
            G4double R = inuclRndm();
            G4double X;
            
            if (NEX == 2) {
              X = 1.0 - std::sqrt(R);
              
            } else {                 
              G4double QEX2 = 1.0 / QEX;
              G4double QEX1 = 1.0 / (QEX-1);
              X = std::pow(0.5 * R, QEX2);
              
              for (G4int i = 0; i < 1000; i++) {
                G4double DX = X * QEX1 * 
                  (1.0 + QEX2 * X * (1.0 - R / std::pow(X, NEX)) / (1.0 - X));
                X -= DX;
                
                if (std::fabs(DX / X) < 0.01) break;  
                
              };
            }; 
            EPART = EB - X * E1;
            EEXS_new = EB - EPART * A / (A-1);
              } // while (EEXS_new < 0.0...
              
              if (itry == itry_max || EEXS_new < 0.0) {
            icase = 0;
            continue;
              }
              
              if (verboseLevel > 2)
            G4cout << " particle " << ptype << " escape " << G4endl;
              
              EPART /= GeV;         // From MeV to GeV
              
              G4InuclElementaryParticle particle(ptype);
              particle.setModel(G4InuclParticle::NonEquilib);
              
              // generate particle momentum
              G4double mass = particle.getMass();
              G4double pmod = std::sqrt(EPART * (2.0 * mass + EPART));
              G4LorentzVector mom = generateWithRandomAngles(pmod,mass);
              
              // Push evaporated paricle into current rest frame
              mom = toTheExitonSystemRestFrame.backToTheLab(mom);
              
              // Adjust quasiparticle and nucleon counts
              G4int QPP_new = QPP;
              G4int QNP_new = QNP;
              
              G4int A_new = A-1;
              G4int Z_new = Z;
              
              if (ptype == 1) {
            QPP_new--;
            Z_new--;
              };
              
              if (ptype == 2) QNP_new--;
              
              if (verboseLevel > 3) {
            G4cout << " nucleus   px " << PEX.px() << " py " << PEX.py()
                   << " pz " << PEX.pz() << " E " << PEX.e() << G4endl
                   << " evaporate px " << mom.px() << " py " << mom.py()
                   << " pz " << mom.pz() << " E " << mom.e() << G4endl;
              }
        
              // New excitation energy depends on residual nuclear state
              G4double mass_new = G4InuclNuclei::getNucleiMass(A_new, Z_new);
              
              EEXS_new = ((PEX-mom).m() - mass_new)*GeV;
              if (EEXS_new < 0.) continue;  // Sanity check for new nucleus
              
              if (verboseLevel > 3)
            G4cout << " EEXS_new " << EEXS_new << G4endl;
              
              PEX -= mom;
              EEXS = EEXS_new;
              
              A = A_new;
              Z = Z_new;
              
              NEX--;
              QEX--;
              QP--;
              QPP = QPP_new;
              QNP = QNP_new;
              
              particle.setMomentum(mom);
              output.addOutgoingParticle(particle);
              ppout += mom;
              if (verboseLevel > 3) {
            G4cout << particle << G4endl
                   << " ppout px " << ppout.px() << " py " << ppout.py()
                   << " pz " << ppout.pz() << " E " << ppout.e() << G4endl;
              }
 
              bad = false;
            }       // while (itry1<itry_max && icase>0
            
            if (itry1 == itry_max) icase = 0;
          } // if (E < 0.) [else]
        }   // if (try_again && icase != 0)
          }     // if (try_again)
        }       // if (icase > 0)
        
        if (icase == 0 && try_again) { // N -> N + 2 
          if (verboseLevel > 3) G4cout << " adding excitons" << G4endl;
 
          G4double TNN = 1.6 * EFN + ESP;
          G4double TNP = 1.6 * EFP + ESP;
          G4double XNUN = 1.0 / (1.6 + ESP / EFN);
          G4double XNUP = 1.0 / (1.6 + ESP / EFP);
          G4double SNN1 = csNN(TNP) * XNUP;
          G4double SNN2 = csNN(TNN) * XNUN;
          G4double SPN1 = csPN(TNP) * XNUP;
          G4double SPN2 = csPN(TNN) * XNUN;
          G4double PP = (QPP * SNN1 + QNP * SPN1) * ZR;
          G4double PN = (QPP * SPN2 + QNP * SNN2) * (AR - ZR);
          G4double PW = PP + PN;
          NEX += 2;
          QEX += 2; 
          QP++;
          QH++;
          AR--;
          
          if (AR > 1) {
        G4double SL = PW * inuclRndm();
        
        if (SL > PP) {
          QNP++;
          QNH++;
        } else {
          QPP++;
          QPH++;
          ZR--;
          if (ZR < 2) try_again = false;
        }  
          } else try_again = false;
        }   // if (icase==0 && try_again)
      } // if (try_again)
    } else try_again = false;   // if (EMN > eexs_cut)
      } else try_again = false;     // if (QEX < sqrg(2*EG)
    } else try_again = false;       // if (A > a_cut ...
  }     // while (try_again)
  
  // everything finished, set output nuclei
 
  if (output.numberOfOutgoingParticles() == 0) {
    output.addOutgoingNucleus(*nuclei_target);
  } else {
    G4LorentzVector pnuc = pin - ppout;
    G4InuclNuclei nuclei(pnuc, A, Z, EEXS, G4InuclParticle::NonEquilib);
    
    if (verboseLevel > 3) G4cout << " remaining nucleus\n" << nuclei << G4endl;
    output.addOutgoingNucleus(nuclei);
  }
 
  validateOutput(0, target, output);    // Check energy conservation, etc.
  return;
}
 
G4double G4NonEquilibriumEvaporator::getMatrixElement(G4int A) const {
 
  if (verboseLevel > 3) {
    G4cout << " >>> G4NonEquilibriumEvaporator::getMatrixElement" << G4endl;
  }
 
  G4double me;
 
  if (A > 150) me = 100.0;
  else if (A > 20) me = 140.0;
  else me = 70.0;
 
  return me;
}
 
G4double G4NonEquilibriumEvaporator::getE0(G4int ) const {
  if (verboseLevel > 3) {
    G4cout << " >>> G4NonEquilibriumEvaporator::getEO" << G4endl;
  }
 
  const G4double e0 = 200.0;
 
  return e0;   
}
 
G4double G4NonEquilibriumEvaporator::getParLev(G4int A, 
                           G4int ) const {
 
  if (verboseLevel > 3) {
    G4cout << " >>> G4NonEquilibriumEvaporator::getParLev" << G4endl;
  }
 
  //  const G4double par = 0.125;
  G4double pl = 0.125 * A;
 
  return pl; 
}