G4DiscreteGammaTransition.cc

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00025 //
00026 // $Id$
00027 //
00028 // -------------------------------------------------------------------
00029 //      GEANT 4 class file 
00030 //
00031 //      CERN, Geneva, Switzerland
00032 //
00033 //      File name:     G4DiscreteGammaTransition
00034 //
00035 //      Author:        Maria Grazia Pia   (pia@genova.infn.it)
00036 // 
00037 //      Creation date: 23 October 1998
00038 //
00039 //      Modifications:
00040 //        15 April 1999, Alessandro Brunengo (Alessandro.Brunengo@ge.infn.it)
00041 //              Added creation time evaluation for products of evaporation
00042 //
00043 //        21 Nov. 2001, Fan Lei (flei@space.qinetiq.com)
00044 //              i) added G4int _nucleusZ initialise it through the constructor
00045 //              ii) modified SelectGamma() to allow the generation of conversion electrons    
00046 //              iii) added #include G4AtomicShells.hh
00047 //      
00048 //        09 Sep. 2002, Fan Lei  (flei@space.qinetiq.com)
00049 //              Added renormalization to determine whether transition leads to
00050 //              electron or gamma in SelectGamma()
00051 //
00052 //        19 April 2010, J. M. Quesada. 
00053 //              Corrections added for taking into account mismatch between tabulated 
00054 //              gamma energies and level energy differences (fake photons eliminated) 
00055 //
00056 //        9 May 2010, V.Ivanchenko
00057 //              Removed unphysical corretions of gamma energy; fixed default particle 
00058 //              as gamma; do not subtract bounding energy in case of electron emmision
00059 //
00060 //                03 November 2011, L. Desorgher
00061 //                              Extend the use of the code for Z>100 by not calling G4AtomicShells::GetBindingEnergy for Z>100
00062 //                              For Z>100 the binding energy is set to 0, the atomic relaxation is not simulated in G4RadDecay
00063 //
00064 // -------------------------------------------------------------------
00065 
00066 #include "G4DiscreteGammaTransition.hh"
00067 #include "G4SystemOfUnits.hh"
00068 #include "Randomize.hh"
00069 #include "G4RandGeneralTmp.hh"
00070 #include "G4AtomicShells.hh"
00071 #include "G4NuclearLevel.hh"
00072 #include "G4NuclearLevelStore.hh"
00073 #include "G4Pow.hh"
00074 
00075 G4DiscreteGammaTransition::G4DiscreteGammaTransition(const G4NuclearLevel& level, G4int Z, G4int A): 
00076   _nucleusZ(Z), _orbitE(-1), _bondE(0.), _aGamma(true), _icm(false), _gammaEnergy(0.), 
00077   _level(level), _excitation(0.),  _gammaCreationTime(0.),_A(A),_Z(Z)
00078 {
00079   _levelManager = 0;
00080   _verbose = 0;
00081   //JMQ: added tolerence in the mismatch
00082   //VI:  increased tolerence 
00083   _tolerance = 10*CLHEP::keV;
00084 }
00085 
00086 G4DiscreteGammaTransition::~G4DiscreteGammaTransition() 
00087 {}
00088 
00089 void G4DiscreteGammaTransition::SelectGamma()
00090 {
00091   // default gamma 
00092   _aGamma = true;    
00093   _gammaEnergy = 0.;
00094   
00095   G4int nGammas = _level.NumberOfGammas();
00096   if (nGammas > 0)
00097     {
00098       G4int iGamma = 0;
00099       if(1 < nGammas) {
00100         G4double random = G4UniformRand();
00101       
00102         //G4cout << "G4DiscreteGammaTransition::SelectGamma  N= " 
00103         //       << nGammas << " rand= " << random << G4endl;
00104         for(iGamma=0; iGamma<nGammas; ++iGamma)
00105           {
00106             //G4cout << iGamma << "  prob= " 
00107             //     << (_level.GammaCumulativeProbabilities())[iGamma] << G4endl;
00108             if(random <= (_level.GammaCumulativeProbabilities())[iGamma])
00109               { break; }
00110           }
00111       }
00112       /*     
00113       G4cout << "Elevel(MeV)= " << _level.Energy()/MeV
00114              << " Etran(MeV)= " << (_level.GammaEnergies())[iGamma]/MeV
00115              << " Eexc(MeV)= " << _excitation/MeV << G4endl;
00116       */
00117 
00118       // VI: do not apply correction here in order do not make 
00119       //     double correction
00120       //G4double eCorrection = _level.Energy() - _excitation;      
00121       //_gammaEnergy = (_level.GammaEnergies())[iGamma] - eCorrection;
00122       _gammaEnergy = (_level.GammaEnergies())[iGamma];
00123             
00124       //JMQ: 
00125       //1)If chosen gamma energy is close enough to excitation energy, 
00126       //  the later is used instead for gamma dacey to gs (it guarantees 
00127       //  energy conservation)
00128       //2)For energy conservation, level energy differences instead of  
00129       //  tabulated gamma energies must be used (origin of final fake photons)
00130       
00131       // VI: remove fake photons - applied only for the last transition
00132       //     do not applied on each transition
00133       if(std::fabs(_excitation - _gammaEnergy) < _tolerance) { 
00134         _gammaEnergy =_excitation;
00135       }
00136 
00137       //  JMQ: Warning: the following check is needed to avoid loops:
00138       //  Due essentially to missing nuclear levels in data files, it is
00139       //  possible that _gammaEnergy is so low as the nucleus doesn't change
00140       //  its level after the transition.
00141       //  When such case is found, force the full deexcitation of the nucleus.
00142       //
00143       //    NOTE: you should force the transition to the next lower level,
00144       //          but this change needs a more complex revision of actual 
00145       //          design.
00146       //          I leave this for a later revision.
00147 
00148       // VI: the check has no sence and we make this very simple
00149       if (_gammaEnergy < _tolerance) { 
00150         _gammaEnergy = _excitation; 
00151       }
00152 
00153       //G4cout << "G4DiscreteGammaTransition::SelectGamma: " << _gammaEnergy 
00154       //             << " _icm: " << _icm << G4endl;
00155 
00156       // now decide whether Internal Coversion electron should be emitted instead
00157       if (_icm) {
00158         G4double random = G4UniformRand();
00159         if ( random <= (_level.TotalConvertionProbabilities())[iGamma]
00160              *(_level.GammaWeights())[iGamma]
00161              /((_level.TotalConvertionProbabilities())[iGamma]*(_level.GammaWeights())[iGamma]
00162                +(_level.GammaWeights())[iGamma])) 
00163           {
00164             G4int iShell = 9;
00165             random = G4UniformRand() ;
00166             if ( random <= (_level.KConvertionProbabilities())[iGamma]) 
00167               { iShell = 0;}
00168             else if ( random <= (_level.L1ConvertionProbabilities())[iGamma]) 
00169               { iShell = 1;}
00170             else if ( random <= (_level.L2ConvertionProbabilities())[iGamma]) 
00171               { iShell = 2;}
00172             else if ( random <= (_level.L3ConvertionProbabilities())[iGamma]) 
00173               { iShell = 3;}    
00174             else if ( random <= (_level.M1ConvertionProbabilities())[iGamma]) 
00175               { iShell = 4;}
00176             else if ( random <= (_level.M2ConvertionProbabilities())[iGamma]) 
00177               { iShell = 5;}
00178             else if ( random <= (_level.M3ConvertionProbabilities())[iGamma]) 
00179               { iShell = 6;}
00180             else if ( random <= (_level.M4ConvertionProbabilities())[iGamma]) 
00181               { iShell = 7;}
00182             else if ( random <= (_level.M5ConvertionProbabilities())[iGamma]) 
00183               { iShell = 8;}
00184             // the following is needed to match the ishell to that used in  G4AtomicShells
00185             if ( iShell == 9) {
00186               if ( (_nucleusZ < 28) && (_nucleusZ > 20)) {
00187                 iShell--;
00188               } else if ( _nucleusZ == 20 || _nucleusZ == 19 ) {
00189                 iShell = iShell -2;
00190               }
00191             }
00192             //L.Desorgher 02/11/2011
00193             //Atomic shell information is available in Geant4 only up top Z=100
00194             //To extend the photo evaporation code to Z>100  the call 
00195             // to G4AtomicShells::GetBindingEnergy should be forbidden for Z>100
00196             _bondE = 0.;
00197             if (_nucleusZ <=100)
00198             _bondE = G4AtomicShells::GetBindingEnergy(_nucleusZ, iShell);
00199             if (_verbose > 0) {
00200               G4cout << "G4DiscreteGammaTransition: _nucleusZ = " <<_nucleusZ 
00201                      << " , iShell = " << iShell  
00202                      << " , Shell binding energy = " << _bondE/keV
00203                      << " keV " << G4endl;
00204             }
00205 
00206             // 09.05.2010 VI : it is an error - cannot subtract bond energy from 
00207             //                 transition energy here
00208             //_gammaEnergy = _gammaEnergy - _bondE; 
00209             //G4cout << "_gammaEnergy = " << _gammaEnergy << G4endl;
00210 
00211             _orbitE = iShell;     
00212             _aGamma = false ;   // emitted is not a gamma now 
00213           }
00214       }
00215       
00216       G4double tau = _level.HalfLife() / G4Pow::GetInstance()->logZ(2);
00217 
00218       //09.05.2010 VI rewrite samling of decay time 
00219       //              assuming ordinary exponential low
00220       _gammaCreationTime = 0.;      
00221       if(tau > 0.0) {  _gammaCreationTime = -tau*std::log(G4UniformRand()); }
00222 
00223     }
00224   return;
00225 }
00226 
00227 G4double G4DiscreteGammaTransition::GetGammaEnergy()
00228 {
00229   return _gammaEnergy;
00230 }
00231 
00232 G4double G4DiscreteGammaTransition::GetGammaCreationTime()
00233 {
00234   return _gammaCreationTime;
00235 }
00236 
00237 void G4DiscreteGammaTransition::SetEnergyFrom(G4double energy)
00238 {
00239   _excitation = energy;
00240 }
00241 
00242 
00243 
00244 
00245 
00246 

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