Geant4: G4PhotoNuclearCrossSection Class Reference

G4PhotoNuclearCrossSection::G4PhotoNuclearCrossSection ( const G4String & name = "PhotoNuclearXS" )

Definition at line 72 of file G4PhotoNuclearCrossSection.cc.

00073  : G4VCrossSectionDataSet(nam)
00074 {}

G4PhotoNuclearCrossSection::~G4PhotoNuclearCrossSection ( ) [virtual]

Definition at line 76 of file G4PhotoNuclearCrossSection.cc.

00077 {
00078   std::vector<G4double*>::iterator pos;
00079   for(pos=GDR.begin(); pos<GDR.end(); pos++)
00080   { delete [] *pos; }
00081   GDR.clear();
00082   for(pos=HEN.begin(); pos<HEN.end(); pos++)
00083   { delete [] *pos; }
00084   HEN.clear();
00085 }

void G4PhotoNuclearCrossSection::CrossSectionDescription ( std::ostream & ) const [virtual]

Reimplemented from G4VCrossSectionDataSet.

Definition at line 88 of file G4PhotoNuclearCrossSection.cc.

00089 {
00090   outFile << "G4PhotoNuclearCrossSection provides the total inelastic\n"
00091           << "cross section for photon interactions with nuclei.  The\n"
00092           << "cross section is a parameterization of data which covers\n" 
00093           << "all incident gamma energies.\n";
00094 }

G4double G4PhotoNuclearCrossSection::GetIsoCrossSection	(	const G4DynamicParticle *	,
		G4int	,
		G4int	,
		const G4Isotope *	,
		const G4Element *	,
		const G4Material *
	)			`[virtual]`

Reimplemented from G4VCrossSectionDataSet.

Definition at line 109 of file G4PhotoNuclearCrossSection.cc.

References G4cerr, G4cout, G4endl, G4DynamicParticle::GetDefinition(), G4DynamicParticle::GetKineticEnergy(), G4ParticleDefinition::GetPDGEncoding(), and CLHEP::detail::n.

00112 {
00113   static const G4double THmin=2.;          // minimum Energy Threshold
00114   static const G4double dE=1.;             // step for the GDR table
00115   static const G4int    nL=105;            // A#of GDResonance points in E 
00116                                            // (each MeV from 2 to 106)
00117   static const G4double Emin=THmin+(nL-1)*dE; // minE for the HighE part
00118   static const G4double Emax=50000.;       // maxE for the HighE part
00119   static const G4int    nH=224;            // A#of HResonance points in lnE
00120   static const G4double milE=std::log(Emin);  // Low logarithm energy for 
00121                                            // the HighE part
00122   static const G4double malE=std::log(Emax);  // High logarithm energy 
00123                                            // (each 2.75 percent)
00124   static const G4double dlE=(malE-milE)/(nH-1); // Step in logarithm energy 
00125                                            // in the HighE part
00126   //
00127   //static const G4double shd=1.075-.0023*std::log(2.);  // HE PomShadowing(D)
00128   static const G4double shd=1.0734;                 // HE PomShadowing(D)
00129   static const G4double shc=0.072;                  // HE Shadowing constant
00130   static const G4double poc=0.0375;                 // HE Pomeron coefficient
00131   static const G4double pos=16.5;                   // HE Pomeron shift
00132   static const G4double reg=.11;                    // HE Reggeon slope
00133   //static const G4double shp=1.075;                  // HE PomShadowing(P)
00134 
00135   // Associative memory for acceleration
00136 
00137   static std::vector <G4int> colN;      // N of calculated nuclei
00138   static std::vector <G4int> colZ;      // Z of calculated nuclei
00139   static std::vector <G4double> spA;    // shadowing coefficients (A-dependent)
00140   static std::vector <G4double> eTH;    // energy threshold (A-dependent)
00141   //
00142   const G4double Energy = aPart->GetKineticEnergy()/MeV;
00143   const G4int targetAtomicNumber = AA; //@@ Nat mixture (?!)
00144   const G4int targZ = ZZ;
00145   const G4int targN = targetAtomicNumber-targZ;
00146 #ifdef debug
00147   G4cout << "G4PhotoNuclearCrossSection::GetCS:N=" << targN << ",Z=" 
00148          << targZ << ",E=" << Energy << G4endl;
00149 #endif
00150   if (Energy<THmin) return 0.;
00151   G4double sigma=0.;
00152   if( aPart->GetDefinition()->GetPDGEncoding() == 22 )
00153   {
00154     G4double A=targN+targZ;
00155     if(targN!=lastN || targZ!=lastZ)   // Otherwise the set of parameters is ready
00156     {
00157       lastN = targN;             // The last N of calculated nucleus
00158       lastZ = targZ;             // The last Z of calculated nucleus
00159       G4int n=colN.size();       // Size of Associated Memory
00160       G4bool in=false;           // The nucleus is in the AssocMem DB
00161       if(n) {
00162         for(G4int i=0; i<n; i++) {
00163           if(colN[i]==targN && colZ[i]==targZ) // Calculated nuclei in DB
00164           {
00165             in=true;          // The nucleus is found in the AssocMem DB
00166             lastGDR=GDR[i];   // Pointer to prepared GDR cross sections
00167             lastHEN=HEN[i];   // Pointer to prepared High Energy cross sections
00168             lastTH =eTH[i];   // Energy Threshold
00169             lastSP =spA[i];   // Shadowing coefficient for UHE
00170           }
00171         }
00172       }
00173 #ifdef debug
00174       G4cout<<"G4PhotoNucCrossSect::GetCS:A="<<A<<",n="<<n<<",in="<<in<<G4endl;
00175 #endif
00176       if(!in)          // Fill the new set of parameters for the new nucleus
00177       {
00178         G4double lnA=std::log(A); // The nucleus is not found in DB. It is new.
00179         if(A==1.) lastSP=1.;      // The Reggeon shadowing (A=1)
00180         else lastSP=A*(1.-shc*lnA);      // The Reggeon shadowing
00181 #ifdef debug
00182         G4cout << "G4PhotoNucCrossSect::GetCS: lnA="
00183                << lnA << ",lastSP=" << lastSP << G4endl;
00184 #endif
00185         lastTH=ThresholdEnergy(targZ, targN); // Energy Threshold
00186 #ifdef debug
00187         G4cout << "G4PhotoNucCrossSect::GetCS: lastTH=" << lastTH << G4endl;
00188 #endif
00189 #ifdef debug3
00190         if(A==3) G4cout << "G4PhotoNucCrossSect::GetCS: lastTH="
00191                         << lastTH << ",lastSP=" << lastSP << G4endl;
00192 #endif
00193         lastGDR = new G4double[nL];  // Allocate memory for the new 
00194                                      // GDR cross sections
00195         lastHEN = new G4double[nH];  // Allocate memory for the new 
00196                                      // HEN cross sections
00197         G4int er=GetFunctions(A,lastGDR,lastHEN); // new ZeroPosition and 
00198                                                   // filling of the functions
00199         if(er<1) G4cerr << "***G4PhotoNucCrossSection::GetCrossSection: A="
00200                         << A << " failed" << G4endl;
00201 #ifdef debug
00202         G4cout<<"G4PhotoNucCrossSect::GetCS: GetFunctions er="<<er<<G4endl;
00203 #endif
00204         colN.push_back(targN);
00205         colZ.push_back(targZ);
00206         GDR.push_back(lastGDR);     // added GDR, found by AH 10/7/02
00207         HEN.push_back(lastHEN);     // added HEN, found by AH 10/7/02
00208         eTH.push_back(lastTH);      // Threshold Energy
00209         spA.push_back(lastSP);      // Pomeron Shadowing
00210       } // End of creation of the new set of parameters
00211     } // End of parameters udate
00212 
00213     //
00214     // =================== NOW the Magic Formula ===================
00215     //
00216     if (Energy<lastTH)
00217     {
00218       lastE=Energy;
00219       lastSig=0.;
00220       return 0.;
00221     }
00222     else if (Energy<Emin)   // GDR region (approximated in E, not in lnE)
00223     {
00224 #ifdef debug
00225       G4cout << "G4PNCS::GetCS: before GDR A=" << A 
00226               << ", nL=" << nL << ",TH=" << THmin << ",dE=" <<dE << G4endl;
00227 #endif
00228       if(A<=1.) sigma=0.;
00229       else      sigma=EquLinearFit(Energy,nL,THmin,dE,lastGDR);
00230 #ifdef debugn
00231       if(sigma<0.) G4cout << "G4PNCS::GetCS:A=" << A << ",E=" << Energy 
00232                           << ",TH=" << THmin << ",dE=" << dE << G4endl;
00233 #endif
00234     }
00235     else if (Energy<Emax)                     // High Energy region
00236     {
00237       G4double lE=std::log(Energy);
00238 #ifdef debug
00239       G4cout << "G4PNCS::GetCS: before HEN nH=" << nH << ",iE=" 
00240              << milE << ",dlE=" << dlE << G4endl;
00241 #endif
00242       sigma=EquLinearFit(lE,nH,milE,dlE,lastHEN);
00243     }
00244     else               // UHE region (calculation, but not so frequent)
00245     {
00246       G4double lE=std::log(Energy);
00247       //G4double sh=shd;
00248       //if(A==1.)sh=shp;
00249       sigma=lastSP*(poc*(lE-pos)+shd*std::exp(-reg*lE));
00250     }
00251 #ifdef debug
00252     G4cout<<"G4PNCS::GetCS: sigma="<<sigma<<G4endl;
00253 #endif
00254 #ifdef pdebug
00255     if(Energy>45000.&&Energy<60000.)G4cout<<"PN::CS:A="<<A<<",E="<<Energy<<",sigma="<<sigma<<G4endl;
00256 #endif
00257   } // End of "sigma" calculation
00258   else return 0.;
00259 
00260   if(sigma<0.) return 0.;
00261   return sigma*millibarn;
00262 }

G4bool G4PhotoNuclearCrossSection::IsIsoApplicable	(	const G4DynamicParticle *	particle,
		G4int	,
		G4int	,
		const G4Element *	,
		const G4Material *
	)			`[virtual]`

Reimplemented from G4VCrossSectionDataSet.

Definition at line 97 of file G4PhotoNuclearCrossSection.cc.

References G4DynamicParticle::GetDefinition(), and G4ParticleDefinition::GetPDGEncoding().

00100 {
00101   G4bool result = false;
00102   if( particle->GetDefinition()->GetPDGEncoding()==22) result = true;
00103   return result;
00104 }


Public Member Functions
	G4PhotoNuclearCrossSection (const G4String &name="PhotoNuclearXS")
virtual	~G4PhotoNuclearCrossSection ()
virtual void	CrossSectionDescription (std::ostream &) const
virtual G4bool	IsIsoApplicable (const G4DynamicParticle particle, G4int, G4int, const G4Element , const G4Material *)
virtual G4double	GetIsoCrossSection (const G4DynamicParticle , G4int, G4int, const G4Isotope , const G4Element , const G4Material )

G4PhotoNuclearCrossSection Class Reference

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation