Gabriele Cosmo
174 lines
8.3 KiB
C++
174 lines
8.3 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software Liscense, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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// $Id: G4GoudsmitSaundersonTable.hh 103884 2017-05-03 08:04:50Z gcosmo $
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//
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// -----------------------------------------------------------------------------
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//
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// GEANT4 Class header file
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//
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// File name: G4GoudsmitSaundersonTable
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//
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// Author: Mihaly Novak / (Omrane Kadri)
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//
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// Creation date: 20.02.2009
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//
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// Class description:
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// Class to handle multiple scattering angular distributions precomputed by
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// using Kawrakow-Bielajew Goudsmit-Saunderson MSC model based on the screened
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// Rutherford DCS for elastic scattering of electrons/positrons [1,2]. This
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// class is used by G4GoudsmitSaundersonMscModel to sample the angular
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// deflection of electrons/positrons after travelling a given path.
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//
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// Modifications:
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// 04.03.2009 V.Ivanchenko cleanup and format according to Geant4 EM style
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// 18.05.2015 M. Novak This class has been completely replaced (only the original
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// class name was kept; class description was also inserted):
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// A new version of Kawrakow-Bielajew Goudsmit-Saunderson MSC model
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// based on the screened Rutherford DCS for elastic scattering of
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// electrons/positrons has been introduced[1,2]. The corresponding MSC
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// angular distributions over a 2D parameter grid have been recomputed
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// and the CDFs are now stored in a variable transformed (smooth) form
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// together with the corresponding rational interpolation parameters.
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// The new version is several times faster, more robust and accurate
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// compared to the earlier version (G4GoudsmitSaundersonMscModel class
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// that use these data has been also completely replaced)
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// 28.04.2017 M. Novak: the GS angular distributions has been recomputed, the
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// data size has been reduced from 16 MB down to 5 MB by using a new
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// representation, the class has been modified significantly due to
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// this new data representation.
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//
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// References:
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// [1] A.F.Bielajew, NIMB, 111 (1996) 195-208
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// [2] I.Kawrakow, A.F.Bielajew, NIMB 134(1998) 325-336
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//
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// -----------------------------------------------------------------------------
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#ifndef G4GoudsmitSaundersonTable_h
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#define G4GoudsmitSaundersonTable_h 1
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#include <vector>
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#include "G4Types.hh"
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class G4GoudsmitSaundersonTable {
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public:
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G4GoudsmitSaundersonTable();
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~G4GoudsmitSaundersonTable();
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void Initialise();
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// structure to store one GS transformed angular distribution (for a given s/lambda_el,s/lambda_elG1)
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struct GSMSCAngularDtr {
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G4int fNumData; // # of data points
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G4double fQScale;
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G4double *fUValues; // array of transformed variables
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G4double *fParamA; // array of interpolation parameters a
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G4double *fParamB; // array of interpolation parameters b
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};
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void LoadMSCData();
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GSMSCAngularDtr* GetOne(G4int indx) {return fGSMSCAngularDistributions1[indx];}
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void Sampling(G4double lambdaval, G4double qval, G4double scra,
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G4double &cost, G4double &sint);
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G4double SampleCosTheta(G4double lambdaval, G4double qval, G4double scra,
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G4double rndm1, G4double rndm2, G4double rndm);
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G4double SampleCosTheta1(G4double lambdaval, G4double qval, G4double scra,
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G4double rndm1, G4double rndm2, G4double rndm);
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G4double SampleCosTheta2(G4double lambdaval, G4double qval, G4double scra,
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G4double rndm1, G4double rndm2, G4double rndm);
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G4double GetScreeningParam(G4double G1);
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// material dependent MSC parameters (computed at initialisation) regarding
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// Moliere's screening parameter
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G4double GetMoliereBc(G4int matindx){return (*fgMoliereBc)[matindx];}
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G4double GetMoliereXc2(G4int matindx){return (*fgMoliereXc2)[matindx];}
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private:
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// initialisation of material dependent Moliere's MSC parameters
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void InitMoliereMSCParams();
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private:
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static bool gIsInitialised; // are the precomputed angular distributions already loaded in?
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static constexpr G4int gLAMBNUM = 64; // # L=s/lambda_el in [fLAMBMIN,fLAMBMAX]
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static constexpr G4int gQNUM1 = 15; // # Q=s/lambda_el G1 in [fQMIN1,fQMAX1] in the 1-st Q grid
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static constexpr G4int gQNUM2 = 32; // # Q=s/lambda_el G1 in [fQMIN2,fQMAX2] in the 2-st Q grid
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static constexpr G4int gNUMSCR1 = 201; // # of screening parameters in the A(G1) function
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static constexpr G4int gNUMSCR2 = 51; // # of screening parameters in the A(G1) function
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static constexpr G4double gLAMBMIN = 1.0; // minimum s/lambda_el
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static constexpr G4double gLAMBMAX = 100000.0; // maximum s/lambda_el
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static constexpr G4double gQMIN1 = 0.001; // minimum s/lambda_el G1 in the 1-st Q grid
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static constexpr G4double gQMAX1 = 0.99; // maximum s/lambda_el G1 in the 1-st Q grid
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static constexpr G4double gQMIN2 = 0.99; // minimum s/lambda_el G1 in the 1-st Q grid
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static constexpr G4double gQMAX2 = 7.99; // maximum s/lambda_el G1 in the 1-st Q grid
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// precomputed A(G1) function with its interpolation parameters
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static constexpr G4double gSCRMIN1 = 1.93214991408357e-12;
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static constexpr G4double gSCRMAX1 = 2.42974344203683e-01;
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static constexpr G4double gSCRMAX2 = 5.50564555556202e+01;
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//
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static const G4double gG1Values1[];
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static const G4double gScrAValues1[];
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static const G4double gScrBValues1[];
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static const G4double gG1Values2[];
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static const G4double gScrAValues2[];
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static const G4double gScrBValues2[];
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G4double fLogLambda0; // ln(gLAMBMIN)
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G4double fLogDeltaLambda; // ln(gLAMBMAX/gLAMBMIN)/(gLAMBNUM-1)
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G4double fInvLogDeltaLambda; // 1/[ln(gLAMBMAX/gLAMBMIN)/(gLAMBNUM-1)]
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G4double fInvDeltaQ1; // 1/[(gQMAX1-gQMIN1)/(gQNUM1-1)]
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G4double fDeltaQ2; // [(gQMAX2-gQMIN2)/(gQNUM2-1)]
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G4double fInvDeltaQ2; // 1/[(gQMAX2-gQMIN2)/(gQNUM2-1)]
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// for the precumputed A(G1) function
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G4double fLogG1FuncMin1;
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G4double fInvLogDeltaG1Func1;
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G4double fLogG1FuncMin2;
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G4double fInvLogDeltaG1Func2;
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// vector to store all GS transformed angular distributions
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std::vector<GSMSCAngularDtr*> fGSMSCAngularDistributions1;
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std::vector<GSMSCAngularDtr*> fGSMSCAngularDistributions2;
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//@{
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/** Precomputed \f$ b_lambda_{c} $\f and \f$ \chi_c^{2} $\f material dependent
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* Moliere parameters that can be used to compute the screening parameter,
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* the elastic scattering cross section (or \f$ \lambda_{e} $\f) under the
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* screened Rutherford cross section approximation. (These are used in
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* G4GoudsmitSaundersonMscModel if fgIsUsePWATotalXsecData is FALSE.)
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*/
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static std::vector<G4double> *fgMoliereBc;
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static std::vector<G4double> *fgMoliereXc2;
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};
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#endif
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