Gabriele Cosmo
187 lines
9.6 KiB
C++
187 lines
9.6 KiB
C++
//
|
|
// ********************************************************************
|
|
// * License and Disclaimer *
|
|
// * *
|
|
// * The Geant4 software is copyright of the Copyright Holders of *
|
|
// * the Geant4 Collaboration. It is provided under the terms and *
|
|
// * conditions of the Geant4 Software License, included in the file *
|
|
// * LICENSE and available at http://cern.ch/geant4/license . These *
|
|
// * include a list of copyright holders. *
|
|
// * *
|
|
// * Neither the authors of this software system, nor their employing *
|
|
// * institutes,nor the agencies providing financial support for this *
|
|
// * work make any representation or warranty, express or implied, *
|
|
// * regarding this software system or assume any liability for its *
|
|
// * use. Please see the license in the file LICENSE and URL above *
|
|
// * for the full disclaimer and the limitation of liability. *
|
|
// * *
|
|
// * This code implementation is the result of the scientific and *
|
|
// * technical work of the GEANT4 collaboration. *
|
|
// * By using, copying, modifying or distributing the software (or *
|
|
// * any work based on the software) you agree to acknowledge its *
|
|
// * use in resulting scientific publications, and indicate your *
|
|
// * acceptance of all terms of the Geant4 Software license. *
|
|
// ********************************************************************
|
|
//
|
|
//
|
|
// ----------------------------------------------------------------------------
|
|
//
|
|
// GEANT4 Class header file
|
|
//
|
|
// File name: G4GSMottCorrection
|
|
//
|
|
// Author: Mihaly Novak
|
|
//
|
|
// Creation date: 23.08.2017
|
|
//
|
|
// Modifications:
|
|
// 26.10.2025 M. Novak: added the related technical note as the proper reference.
|
|
//
|
|
// Class description:
|
|
// An object of this calss is used in the G4GoudsmitSaundersonTable when Mott-correction
|
|
// was required by the user in the G4GoudsmitSaundersonMscModel.
|
|
// The class is responsible to handle pre-computed Mott correction (rejection) functions
|
|
// obtained as a ratio of GS angular distributions computed based on the Screened-Rutherford
|
|
// DCS to GS angular distributions computed based on a more accurate corrected DCS_{cor}.
|
|
// The DCS used to compute the accurate Goudsmit-Saunderson angular distributions is [1]:
|
|
// DCS_{cor} = DCS_{SR}x[ DCS_{R}/DCS_{Mott}] where :
|
|
// # DCS_{SR} is the relativistic Screened-Rutherford DCS (first Born approximate
|
|
// solution of the Klein-Gordon i.e. relativistic Schrodinger equation =>
|
|
// scattering of spinless e- on exponentially screened Coulomb potential)
|
|
// note: the default (without using Mott-correction) GS angular distributions
|
|
// are based on this DCS_{SR} with Moliere's screening parameter!
|
|
// # DCS_{R} is the Rutherford DCS which is the same as above but without
|
|
// screening
|
|
// # DCS_{Mott} is the Mott DCS i.e. solution of the Dirac equation with a bare
|
|
// Coulomb potential i.e. scattering of particles with spin (e- or e+) on a
|
|
// point-like unscreened Coulomb potential [2]
|
|
// # moreover, the screening parameter of the DCS_{cor} was determined such that
|
|
// the DCS_{cor} with this corrected screening parameter reproduce the first
|
|
// transport cross sections obtained from the corresponding most accurate DCS [3].
|
|
// Unlike the default GS, the Mott-corrected angular distributions are particle type
|
|
// (different for e- and e+ <= the DCS_{Mott} and the screening correction) and target
|
|
// (Z and material) dependent.
|
|
// [1] I.Kawrakow, E.Mainegra-Hing, D.W.O.Rogers, F.Tessier,B.R.B.Walters, NRCC
|
|
// Report PIRS-701 (2013)
|
|
// [2] N.F. Mott, Proc. Roy. Soc. (London) A 124 (1929) 425.
|
|
// [3] F.Salvat, A.Jablonski, C.J. Powell, CPC 165(2005) 157-190
|
|
//
|
|
// References:
|
|
// M. Novak: https://arxiv.org/abs/2410.13361
|
|
//
|
|
// -----------------------------------------------------------------------------
|
|
|
|
#ifndef G4GSMottCorrection_h
|
|
#define G4GSMottCorrection_h 1
|
|
|
|
#include <CLHEP/Units/SystemOfUnits.h>
|
|
|
|
#include "globals.hh"
|
|
|
|
#include <vector>
|
|
#include <string>
|
|
#include <sstream>
|
|
|
|
class G4Material;
|
|
class G4Element;
|
|
|
|
|
|
class G4GSMottCorrection {
|
|
public:
|
|
G4GSMottCorrection(G4bool iselectron=true);
|
|
|
|
~G4GSMottCorrection();
|
|
|
|
void Initialise();
|
|
|
|
void GetMottCorrectionFactors(G4double logekin, G4double beta2, G4int matindx,
|
|
G4double &mcToScr, G4double &mcToQ1, G4double &mcToG2PerG1);
|
|
|
|
G4double GetMottRejectionValue(G4double logekin, G4double G4beta2, G4double q1, G4double cost,
|
|
G4int matindx, G4int &ekindx, G4int &deltindx);
|
|
|
|
static G4int GetMaxZet() { return gMaxZet; }
|
|
|
|
private:
|
|
void InitMCDataPerElement();
|
|
|
|
void InitMCDataPerMaterials();
|
|
|
|
void LoadMCDataElement(const G4Element*);
|
|
|
|
void ReadCompressedFile(const std::string& fname, std::istringstream &iss);
|
|
|
|
void InitMCDataMaterial(const G4Material*);
|
|
//
|
|
// dat structures
|
|
struct DataPerDelta {
|
|
G4double fSA; // a,b,c,d spline interpolation parameters for the last \sin(0.5\theta) bin
|
|
G4double fSB;
|
|
G4double fSC;
|
|
G4double fSD;
|
|
G4double *fRejFuntion; // rejection func. for a given E_{kin}, \delta, e^-/e^+ over the \sin(0.5\theta) grid
|
|
};
|
|
|
|
struct DataPerEkin {
|
|
G4double fMCScreening; // correction factor to Moliere screening parameter
|
|
G4double fMCFirstMoment; // correction factor to first moment
|
|
G4double fMCSecondMoment; // correction factor to second
|
|
DataPerDelta **fDataPerDelta; // per delta value data structure for each delta values
|
|
};
|
|
|
|
// either per material or per Z
|
|
struct DataPerMaterial {
|
|
DataPerEkin **fDataPerEkin; // per kinetic energy data structure for each kinetic energy value
|
|
};
|
|
//
|
|
void AllocateDataPerMaterial(DataPerMaterial*);
|
|
void DeAllocateDataPerMaterial(DataPerMaterial*);
|
|
void ClearMCDataPerElement();
|
|
void ClearMCDataPerMaterial();
|
|
//
|
|
// data members:
|
|
// - Mott correction data are computed over a :
|
|
// I. Kinetic energy grid [both rejection functions and correction factors]:
|
|
// 1. kinetic energy grid from 1[keV] - 100[keV] with log-spacing 16 points:
|
|
// # linear interpolation on \ln[E_{kin}] will be used
|
|
// 2. \beta^2 grid from E_{kin} = 100[keV](~0.300546) - \beta^2=0.9999(~50.5889MeV]) with linear spacing 16 points:
|
|
// # linear interpolation on \beta^2 will be used
|
|
// 3. the overall kinetic energy grid is from E_{kin}=1[keV] - E_{kin}<=\beta^2=0.9999(~50.5889MeV]) with 31 points
|
|
// II. Delta value grid [rejection functions at a given kinetic energy(also depends on \theta;Z,e-/e+)]:
|
|
// 1. \delta=2 Q_{1SR} (\eta_{MCcor})/ [1-2 Q_{1SR} (\eta_{MCcor})] where Q_{1SR} is the first moment i.e.
|
|
// Q_{1SR}(\eta_{MCcor}) =s/\lambda_{el}G_{1SR}(\eta_{MCcor}) where s/\lambda_{el} is the mean number of elastic
|
|
// scattering along the path s and G_{1SR}(\eta_{MCcor}) is the first, Screened-Rutherford transport coefficient
|
|
// but computed by using the Mott-corrected Moliere screening parameter
|
|
// 2. the delta value grid is from [0(1e-3) - 0.9] with linear spacing of 28 points:
|
|
// # linear interpolation will be used on \delta
|
|
// III. \sin(0.5\theta) grid[rejection function at a given kinetic energy - delta value pair (also depends on Z,e-/e+)]:
|
|
// 1. 32 \sin(0.5\theta) pints between [0,1] with linear spacing: # linear interpolation on \sin(0.5\theta) will
|
|
// be used exept the last bin where spline is used (the corresponding 4 spline parameters are also stored)
|
|
private:
|
|
G4bool fIsElectron;
|
|
static constexpr G4int gNumEkin = 31; // number of kinetic energy grid points for Mott correction
|
|
static constexpr G4int gNumBeta2 = 16; // \beta^2 values between [fMinBeta2-fMaxBeta2]
|
|
static constexpr G4int gNumDelta = 28; // \delta values between [0(1.e-3)-0.9]
|
|
static constexpr G4int gNumAngle = 32; //
|
|
static constexpr G4int gMaxZet = 98; // max. Z for which Mott-correction data were computed (98)
|
|
static constexpr G4double gMinEkin = 1.*CLHEP::keV; // minimum kinetic energy value
|
|
static constexpr G4double gMidEkin = 100.*CLHEP::keV; // kinetic energy at the border of the E_{kin}-\beta^2 grids
|
|
static constexpr G4double gMaxBeta2 = 0.9999; // maximum \beta^2 value
|
|
static constexpr G4double gMaxDelta = 0.9; // maximum \delta value (the minimum is 0(1.e-3))
|
|
//
|
|
G4double fMaxEkin; // from max fMaxBeta2 = 0.9999 (~50.5889 [MeV])
|
|
G4double fLogMinEkin; // \ln[fMinEkin]
|
|
G4double fInvLogDelEkin; // 1/[\ln(fMidEkin/fMinEkin)/(fNumEkin-fNumBeta2)]
|
|
G4double fMinBeta2; // <= E_{kin}=100 [keV] (~0.300546)
|
|
G4double fInvDelBeta2; // 1/[(fMaxBeta2-fMinBeta2)/(fNumBeta2-1)]
|
|
G4double fInvDelDelta; // 1/[0.9/(fNumDelta-1)]
|
|
G4double fInvDelAngle; // 1/[(1-0)/fNumAngle-1]
|
|
//
|
|
static const std::string gElemSymbols[];
|
|
//
|
|
std::vector<DataPerMaterial*> fMCDataPerElement; // size will be gMaxZet+1; won't be null only at used Z indices
|
|
std::vector<DataPerMaterial*> fMCDataPerMaterial; // size will #materials; won't be null only at used mat. indices
|
|
};
|
|
|
|
#endif // G4GSMottCorrection_h
|