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2018-12-07 15:15:39 +01:00

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//
// ********************************************************************
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// * *
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//
//
// ----------------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name: G4SBBremTable
//
// Author: Mihaly Novak
//
// Creation date: 15.07.2018
//
// Modifications:
//
// Class description:
//
// Utility class to handle sampling tables for the Seltzer-Berger scalled brems-
// strahlung differential cross sections. It makes possible fast (significantly
// faster than the rejection) sampling of the emitted photon energy in case of
// interactions. An object from this class is supposed to be a member of the
// Seltzer-Berger model for e-/e+ bremsstrahlung photon emission model. Note,
// that one object from this class can handle both e- and e+ cases (containes
// e+ correction in the SampleEnergyTransfer method only).
//
// ----------------------------------------------------------------------------
#ifndef G4SBBremTable_h
#define G4SBBremTable_h 1
#include "globals.hh"
#include "G4String.hh"
#include <vector>
// forward declar
class G4MaterialCutsCouple;
class G4SBBremTable {
public:
// CTR/DTR
G4SBBremTable();
~G4SBBremTable();
// loads and init sampling tables: lowe/highe are the low/high energy usage
// limits of the corresponding Seltzerberger-model.
void Initialize(const G4double lowe, const G4double highe);
// clean away all sampling tables and makes ready for re-initialisation
void ClearSamplingTables();
// run-time method to sample energy transferred to the emitted photon
double SampleEnergyTransfer(const G4double eekin, const G4double leekin,
const G4double gcut , const G4double dielSupConst,
const G4int izet , const G4int matCutIndx,
const bool iselectron);
// used only for development: print out table related information
// void Dump();
private:
void BuildSamplingTables();
void InitSamplingTables();
void LoadSTGrid();
void LoadSamplingTables(G4int iz);
void ReadCompressedFile(const G4String &fname, std::istringstream &iss);
private:
// Sampling-Table point: describes one [E_i],[kappa_j] point
struct STPoint {
G4double fCum; // value of the cumulative function
G4double fParA; // rational function approximation based interp. parameter
G4double fParB; // rational function approximation based interp. parameter
};
// Sampling-Table: describes one [E_j] e- energy point i.e. one Table
struct STable {
// cumulative values for the kappa-cuts: kappa_cut_i=E_gamma_cut_i/E_el_j
std::vector<G4double> fCumCutValues;
// as many STPoint-s as kappa values
std::vector<STPoint> fSTable;
};
// Sampling-Tables for a given Z:
// describes all tables (i.e. for all e- energies) for a given element (Z)
struct SamplingTablePerZ {
SamplingTablePerZ() : fNumGammaCuts(0), fMinElEnergyIndx(-1), fMaxElEnergyIndx(-1) {}
size_t fNumGammaCuts; // number of gamma-cut for this
G4int fMinElEnergyIndx; // max(i) such E_i <= E for all E
G4int fMaxElEnergyIndx; // min(i) such E_i >= E for all E
std::vector<STable*> fTablesPerEnergy; // as many table as e-ekin grid point
//the different gamma-cut values that are defined for this element(Z) and ln
std::vector<G4double> fGammaECuts;
std::vector<G4double> fLogGammaECuts;
// the couple index element stores the corresponding (sorted) gamma-cut index
std::vector<size_t> fMatCutIndxToGamCutIndx;
// temporary vector to store some indecis during initialisation
std::vector< std::vector<size_t> > fGamCutIndxToMatCutIndx;
};
// simple linear search: most of the time faster than anything in our case
G4int LinSearch(const std::vector<STPoint>& vect,
const G4int size,
const G4double val);
private:
// pre-prepared sampling tables are available:
G4int fMaxZet; // max Z number
G4int fNumElEnergy; // # e- kine (E_k) per Z
G4int fNumKappa; // # red. photon eners per E_k
// min/max electron kinetic energy usage limits
G4double fUsedLowEenergy;
G4double fUsedHighEenergy;
G4double fLogMinElEnergy;
G4double fILDeltaElEnergy;
// e- kinetic energy and reduced photon energy grids and tehir logarithms
std::vector<G4double> fElEnergyVect;
std::vector<G4double> fLElEnergyVect;
std::vector<G4double> fKappaVect;
std::vector<G4double> fLKappaVect;
// container to store samplingtables per Z (size is fMaxZet+1)
std::vector<SamplingTablePerZ*> fSBSamplingTables;
};
#endif