include/Geant4/G4SBBremTable.hh

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0025 //
0026 //
0027 // ----------------------------------------------------------------------------
0028 //
0029 // GEANT4 Class header file
0030 //
0031 //
0032 // File name:     G4SBBremTable
0033 //
0034 // Author:        Mihaly Novak
0035 //
0036 // Creation date: 15.07.2018
0037 //
0038 // Modifications:
0039 //
0040 // Class description:
0041 //
0042 // Utility class to handle sampling tables for the Seltzer-Berger scalled brems-
0043 // strahlung differential cross sections. It makes possible fast (significantly
0044 // faster than the rejection) sampling of the emitted photon energy in case of
0045 // interactions. An object from this class is supposed to be a member of the
0046 // Seltzer-Berger model for e-/e+ bremsstrahlung photon emission model. Note,
0047 // that one object from this class can handle both e- and e+ cases (containes
0048 // e+ correction in the SampleEnergyTransfer method only).
0049 //
0050 // ----------------------------------------------------------------------------
0051
0052 #ifndef G4SBBremTable_h
0053 #define G4SBBremTable_h 1
0054
0055 #include "globals.hh"
0056 #include "G4String.hh"
0057
0058 #include <vector>
0059
0060 // forward declar
0061 class G4MaterialCutsCouple;
0062
0063 class G4SBBremTable {
0064
0065 public:
0066    // CTR/DTR
0067    G4SBBremTable();
0068
0069   ~G4SBBremTable();
0070
0071    // loads and init sampling tables: lowe/highe are the low/high energy usage
0072    // limits of the corresponding Seltzerberger-model.
0073    void Initialize(const G4double lowe, const G4double highe);
0074
0075    // clean away all sampling tables and makes ready for re-initialisation
0076    void ClearSamplingTables();
0077
0078    // run-time method to sample energy transferred to the emitted photon
0079    double SampleEnergyTransfer(const G4double eekin, const G4double leekin,
0080                                const G4double gcut , const G4double dielSupConst,
0081                                const G4int    izet , const G4int matCutIndx,
0082                                const bool     iselectron);
0083
0084    // used only for development: print out table related information
0085    // void Dump();
0086
0087 private:
0088
0089   void  BuildSamplingTables();
0090
0091   void  InitSamplingTables();
0092
0093   void  LoadSTGrid();
0094
0095   void  LoadSamplingTables(G4int iz);
0096
0097   void  ReadCompressedFile(const G4String &fname, std::istringstream &iss);
0098
0099 private:
0100
0101   // Sampling-Table point: describes one [E_i],[kappa_j] point
0102   struct STPoint {
0103     G4double fCum;    // value of the cumulative function
0104     G4double fParA;   // rational function approximation based interp. parameter
0105     G4double fParB;   // rational function approximation based interp. parameter
0106   };
0107
0108   // Sampling-Table: describes one [E_j] e- energy point i.e. one Table
0109   struct STable {
0110     // cumulative values for the kappa-cuts: kappa_cut_i=E_gamma_cut_i/E_el_j
0111     std::vector<G4double> fCumCutValues;
0112     // as many STPoint-s as kappa values
0113     std::vector<STPoint>  fSTable;
0114   };
0115
0116   // Sampling-Tables for a given Z:
0117   // describes all tables (i.e. for all e- energies) for a given element (Z)
0118   struct SamplingTablePerZ {
0119     SamplingTablePerZ() : fNumGammaCuts(0), fMinElEnergyIndx(-1), fMaxElEnergyIndx(-1) {}
0120     size_t                fNumGammaCuts;     // number of gamma-cut for this
0121     G4int                 fMinElEnergyIndx;  // max(i) such E_i <= E for all E
0122     G4int                 fMaxElEnergyIndx;  // min(i) such E_i >= E for all E
0123     std::vector<STable*>  fTablesPerEnergy;  // as many table as e-ekin grid point
0124     //the different gamma-cut values that are defined for this element(Z) and ln
0125     std::vector<G4double> fGammaECuts;
0126     std::vector<G4double> fLogGammaECuts;
0127     // the couple index element stores the corresponding (sorted) gamma-cut index
0128     std::vector<size_t>   fMatCutIndxToGamCutIndx;
0129     // temporary vector to store some indecis during initialisation
0130     std::vector< std::vector<size_t> >   fGamCutIndxToMatCutIndx;
0131   };
0132
0133   // simple linear search: most of the time faster than anything in our case
0134   G4int LinSearch(const std::vector<STPoint>& vect,
0135                   const G4int size,
0136                   const G4double val);
0137
0138 private:
0139
0140   // pre-prepared sampling tables are available:
0141   G4int                           fMaxZet;      // max Z number
0142   G4int                           fNumElEnergy; // # e- kine (E_k) per Z
0143   G4int                           fNumKappa;    // # red. photon eners per E_k
0144
0145   // min/max electron kinetic energy usage limits
0146   G4double                        fUsedLowEenergy;
0147   G4double                        fUsedHighEenergy;
0148   G4double                        fLogMinElEnergy;
0149   G4double                        fILDeltaElEnergy;
0150
0151   // e- kinetic energy and reduced photon energy grids and tehir logarithms
0152   std::vector<G4double>           fElEnergyVect;
0153   std::vector<G4double>           fLElEnergyVect;
0154   std::vector<G4double>           fKappaVect;
0155   std::vector<G4double>           fLKappaVect;
0156
0157   // container to store samplingtables per Z (size is fMaxZet+1)
0158   std::vector<SamplingTablePerZ*> fSBSamplingTables;
0159
0160 };
0161
0162 #endif