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25 //
26 //
27 // ----------------------------------------------------------------------------
28 //
29 // GEANT4 Class header file
30 //
31 //
32 // File name: G4SBBremTable
33 //
34 // Author: Mihaly Novak
35 //
36 // Creation date: 15.07.2018
37 //
38 // Modifications:
39 //
40 // Class description:
41 //
42 // Utility class to handle sampling tables for the Seltzer-Berger scalled brems-
43 // strahlung differential cross sections. It makes possible fast (significantly
44 // faster than the rejection) sampling of the emitted photon energy in case of
45 // interactions. An object from this class is supposed to be a member of the
46 // Seltzer-Berger model for e-/e+ bremsstrahlung photon emission model. Note,
47 // that one object from this class can handle both e- and e+ cases (containes
48 // e+ correction in the SampleEnergyTransfer method only).
49 //
50 // ----------------------------------------------------------------------------
51
52 #ifndef G4SBBremTable_h
53 #define G4SBBremTable_h 1
54
55 #include "globals.hh"
56 #include "G4String.hh"
57
58 #include <vector>
59
60 // forward declar
61 class G4MaterialCutsCouple;
62
63 class G4SBBremTable {
64
65 public:
66 // CTR/DTR
67 G4SBBremTable();
68
69 ~G4SBBremTable();
70
71 // loads and init sampling tables: lowe/highe are the low/high energy usage
72 // limits of the corresponding Seltzerberger-model.
73 void Initialize(const G4double lowe, const G4double highe);
74
75 // clean away all sampling tables and makes ready for re-initialisation
76 void ClearSamplingTables();
77
78 // run-time method to sample energy transferred to the emitted photon
79 double SampleEnergyTransfer(const G4double eekin, const G4double leekin,
80 const G4double gcut , const G4double dielSupConst,
81 const G4int izet , const G4int matCutIndx,
82 const bool iselectron);
83
84 // used only for development: print out table related information
85 // void Dump();
86
87 private:
88
89 void BuildSamplingTables();
90
91 void InitSamplingTables();
92
93 void LoadSTGrid();
94
95 void LoadSamplingTables(G4int iz);
96
97 void ReadCompressedFile(const G4String &fname, std::istringstream &iss);
98
99 private:
100
101 // Sampling-Table point: describes one [E_i],[kappa_j] point
102 struct STPoint {
103 G4double fCum; // value of the cumulative function
104 G4double fParA; // rational function approximation based interp. parameter
105 G4double fParB; // rational function approximation based interp. parameter
106 };
107
108 // Sampling-Table: describes one [E_j] e- energy point i.e. one Table
109 struct STable {
110 // cumulative values for the kappa-cuts: kappa_cut_i=E_gamma_cut_i/E_el_j
111 std::vector<G4double> fCumCutValues;
112 // as many STPoint-s as kappa values
113 std::vector<STPoint> fSTable;
114 };
115
116 // Sampling-Tables for a given Z:
117 // describes all tables (i.e. for all e- energies) for a given element (Z)
118 struct SamplingTablePerZ {
119 SamplingTablePerZ() : fNumGammaCuts(0), fMinElEnergyIndx(-1), fMaxElEnergyIndx(-1) {}
120 size_t fNumGammaCuts; // number of gamma-cut for this
121 G4int fMinElEnergyIndx; // max(i) such E_i <= E for all E
122 G4int fMaxElEnergyIndx; // min(i) such E_i >= E for all E
123 std::vector<STable*> fTablesPerEnergy; // as many table as e-ekin grid point
124 //the different gamma-cut values that are defined for this element(Z) and ln
125 std::vector<G4double> fGammaECuts;
126 std::vector<G4double> fLogGammaECuts;
127 // the couple index element stores the corresponding (sorted) gamma-cut index
128 std::vector<size_t> fMatCutIndxToGamCutIndx;
129 // temporary vector to store some indecis during initialisation
130 std::vector< std::vector<size_t> > fGamCutIndxToMatCutIndx;
131 };
132
133 // simple linear search: most of the time faster than anything in our case
134 G4int LinSearch(const std::vector<STPoint>& vect,
135 const G4int size,
136 const G4double val);
137
138 private:
139
140 // pre-prepared sampling tables are available:
141 G4int fMaxZet; // max Z number
142 G4int fNumElEnergy; // # e- kine (E_k) per Z
143 G4int fNumKappa; // # red. photon eners per E_k
144
145 // min/max electron kinetic energy usage limits
146 G4double fUsedLowEenergy;
147 G4double fUsedHighEenergy;
148 G4double fLogMinElEnergy;
149 G4double fILDeltaElEnergy;
150
151 // e- kinetic energy and reduced photon energy grids and tehir logarithms
152 std::vector<G4double> fElEnergyVect;
153 std::vector<G4double> fLElEnergyVect;
154 std::vector<G4double> fKappaVect;
155 std::vector<G4double> fLKappaVect;
156
157 // container to store samplingtables per Z (size is fMaxZet+1)
158 std::vector<SamplingTablePerZ*> fSBSamplingTables;
159
160 };
161
162 #endif
163