Gabriele Cosmo
485 lines
18 KiB
C++
485 lines
18 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 License, 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: G4ComptonScattering52.cc,v 1.3 2006/10/16 15:26:49 vnivanch Exp $
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// GEANT4 tag $Name: geant4-08-02 $
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//
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//
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//------------ G4ComptonScattering52 physics process -----------------------------
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// by Michel Maire, April 1996
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//
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// 28-05-96, DoIt() small change in ElecDirection, by M.Maire
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// 10-06-96, simplification in ComputeMicroscopicCrossSection(), by M.Maire
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// 21-06-96, SetCuts implementation, M.Maire
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// 13-09-96, small changes in DoIt for better efficiency. Thanks to P.Urban
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// 06-01-97, crossection table + meanfreepath table, M.Maire
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// 05-03-97, new Physics scheme, M.Maire
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// 28-03-97, protection in BuildPhysicsTable, M.Maire
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// 07-04-98, remove 'tracking cut' of the scattered gamma, MMa
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// 04-06-98, in DoIt, secondary production condition:
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// range>std::min(threshold,safety)
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// 13-08-98, new methods SetBining() PrintInfo()
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// 15-12-98, cross section=0 below 10 keV
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// 28-05-01, V.Ivanchenko minor changes to provide ANSI -wall compilation
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// 13-07-01, DoIt: suppression of production cut for the electron (mma)
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// 03-08-01, new methods Store/Retrieve PhysicsTable (mma)
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// 06-08-01, BuildThePhysicsTable() called from constructor (mma)
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// 17-09-01, migration of Materials to pure STL (mma)
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// 20-09-01, DoIt: fminimalEnergy = 1*eV (mma)
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// 01-10-01, come back to BuildPhysicsTable(const G4ParticleDefinition&)
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// 17-04-02, LowestEnergyLimit = 1*keV
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// 26-05-04, cross section parametrization improved for low energy :
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// Egamma <~ 15 keV (Laszlo)
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// 08-11-04, Remove Store/Retrieve tables (V.Ivanchenko)
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// 04-05-05, Add 52 to class name (V.Ivanchenko)
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// -----------------------------------------------------------------------------
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#include "G4ComptonScattering52.hh"
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#include "G4UnitsTable.hh"
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#include "G4PhysicsTableHelper.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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using namespace std;
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G4ComptonScattering52::G4ComptonScattering52(const G4String& processName,
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G4ProcessType type):G4VDiscreteProcess (processName, type),
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theCrossSectionTable(NULL),
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theMeanFreePathTable(NULL),
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LowestEnergyLimit ( 1*keV),
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HighestEnergyLimit(100*GeV),
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NumbBinTable(80),
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fminimalEnergy(1*eV)
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{}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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// destructor
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G4ComptonScattering52::~G4ComptonScattering52()
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{
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if (theCrossSectionTable) {
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theCrossSectionTable->clearAndDestroy();
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delete theCrossSectionTable;
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}
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if (theMeanFreePathTable) {
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theMeanFreePathTable->clearAndDestroy();
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delete theMeanFreePathTable;
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4bool G4ComptonScattering52::IsApplicable( const G4ParticleDefinition& particle)
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{
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return ( &particle == G4Gamma::Gamma() );
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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void G4ComptonScattering52::SetPhysicsTableBining(
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G4double lowE, G4double highE, G4int nBins)
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{
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LowestEnergyLimit = lowE; HighestEnergyLimit = highE; NumbBinTable = nBins;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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void G4ComptonScattering52::BuildPhysicsTable(const G4ParticleDefinition&)
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// Build cross section and mean free path tables
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{
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G4double LowEdgeEnergy, Value;
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G4PhysicsLogVector* ptrVector;
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// Build cross section per atom tables for the Compton Scattering process
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if (theCrossSectionTable) {
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theCrossSectionTable->clearAndDestroy(); delete theCrossSectionTable;}
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theCrossSectionTable = new G4PhysicsTable(G4Element::GetNumberOfElements());
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const G4ElementTable* theElementTable = G4Element::GetElementTable();
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G4double AtomicNumber;
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size_t J;
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for ( J=0 ; J < G4Element::GetNumberOfElements(); J++ )
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{
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//create physics vector then fill it ....
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ptrVector = new G4PhysicsLogVector(LowestEnergyLimit,HighestEnergyLimit,
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NumbBinTable );
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AtomicNumber = (*theElementTable)[J]->GetZ();
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for ( G4int i = 0 ; i < NumbBinTable ; i++ )
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{
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LowEdgeEnergy = ptrVector->GetLowEdgeEnergy(i);
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Value = ComputeCrossSectionPerAtom(LowEdgeEnergy, AtomicNumber);
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ptrVector->PutValue(i,Value);
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}
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theCrossSectionTable->insertAt( J , ptrVector ) ;
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}
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// Build mean free path table for the Compton Scattering process
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if (theMeanFreePathTable) {
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theMeanFreePathTable->clearAndDestroy(); delete theMeanFreePathTable;}
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theMeanFreePathTable= new G4PhysicsTable(G4Material::GetNumberOfMaterials());
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const G4MaterialTable* theMaterialTable = G4Material::GetMaterialTable();
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G4Material* material;
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for ( J=0 ; J < G4Material::GetNumberOfMaterials(); J++ )
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{
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//create physics vector then fill it ....
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ptrVector = new G4PhysicsLogVector(LowestEnergyLimit,HighestEnergyLimit,
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NumbBinTable ) ;
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material = (*theMaterialTable)[J];
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for ( G4int i = 0 ; i < NumbBinTable ; i++ )
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{
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LowEdgeEnergy = ptrVector->GetLowEdgeEnergy( i ) ;
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Value = ComputeMeanFreePath( LowEdgeEnergy, material);
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ptrVector->PutValue( i , Value ) ;
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}
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theMeanFreePathTable->insertAt( J , ptrVector ) ;
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}
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PrintInfoDefinition();
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4ComptonScattering52::ComputeCrossSectionPerAtom
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(G4double GammaEnergy, G4double Z)
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// Calculates the cross section per atom in GEANT4 internal units.
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// A parametrized formula from L. Urban is used to estimate
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// the total cross section.
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// It gives a good description of the data from 10 keV to 100/Z GeV.
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// lower limit 1 keV now with a correction for low energy
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{
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G4double CrossSection = 0.0 ;
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if ( Z < 1. ) return CrossSection;
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if ( GammaEnergy < 1.*keV ) return CrossSection;
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if ( GammaEnergy > (100.*GeV/Z) ) return CrossSection;
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static const G4double a = 20.0 , b = 230.0 , c = 440.0;
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static const G4double
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d1= 2.7965e-1*barn, d2=-1.8300e-1*barn, d3= 6.7527 *barn, d4=-1.9798e+1*barn,
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e1= 1.9756e-5*barn, e2=-1.0205e-2*barn, e3=-7.3913e-2*barn, e4= 2.7079e-2*barn,
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f1=-3.9178e-7*barn, f2= 6.8241e-5*barn, f3= 6.0480e-5*barn, f4= 3.0274e-4*barn;
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G4double p1Z = Z*(d1 + e1*Z + f1*Z*Z), p2Z = Z*(d2 + e2*Z + f2*Z*Z),
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p3Z = Z*(d3 + e3*Z + f3*Z*Z), p4Z = Z*(d4 + e4*Z + f4*Z*Z);
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G4double T0 = 15*keV; if (Z == 1.) T0 = 40*keV;
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G4double X = max(GammaEnergy, T0) / electron_mass_c2;
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CrossSection = p1Z*log(1.+2*X)/X
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+ (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
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// modification for low energy. (special case for Hydrogen)
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if (GammaEnergy < T0) {
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G4double dT0 = 1.*keV;
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X = (T0+dT0) / electron_mass_c2 ;
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G4double sigma = p1Z*log(1.+2*X)/X
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+ (p2Z + p3Z*X + p4Z*X*X)/(1. + a*X + b*X*X + c*X*X*X);
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G4double c1 = -T0*(sigma-CrossSection)/(CrossSection*dT0);
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G4double c2 = 0.150; if (Z > 1.) c2 = 0.375-0.0556*log(Z);
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G4double y = log(GammaEnergy/T0);
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CrossSection *= exp(-y*(c1+c2*y));
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}
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return CrossSection;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4ComptonScattering52::ComputeMeanFreePath(G4double GammaEnergy,
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G4Material* aMaterial)
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// returns the gamma mean free path in GEANT4 internal units
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{
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const G4ElementVector* theElementVector = aMaterial->GetElementVector() ;
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const G4double* NbOfAtomsPerVolume = aMaterial->GetVecNbOfAtomsPerVolume();
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G4double SIGMA = 0.;
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for ( size_t elm=0 ; elm < aMaterial->GetNumberOfElements() ; elm++ )
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{
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SIGMA += NbOfAtomsPerVolume[elm] *
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ComputeCrossSectionPerAtom(GammaEnergy,
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(*theElementVector)[elm]->GetZ());
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}
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return SIGMA > DBL_MIN ? 1./SIGMA : DBL_MAX;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4ComptonScattering52::GetCrossSectionPerAtom(
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G4DynamicParticle* aDynamicGamma,
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G4Element* anElement)
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// gives the microscopic total cross section in GEANT4 internal units
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{
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G4double crossSection;
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G4double GammaEnergy = aDynamicGamma->GetKineticEnergy();
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G4bool isOutRange ;
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if (GammaEnergy < LowestEnergyLimit || GammaEnergy > HighestEnergyLimit)
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crossSection = 0.;
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else
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crossSection = (*theCrossSectionTable)(anElement->GetIndex())->
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GetValue(GammaEnergy, isOutRange);
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return crossSection;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4ComptonScattering52::GetMeanFreePath(const G4Track& aTrack,
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G4double,
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G4ForceCondition*)
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// returns the gamma mean free path in GEANT4 internal units
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{
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const G4DynamicParticle* aDynamicGamma = aTrack.GetDynamicParticle();
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G4double GammaEnergy = aDynamicGamma->GetKineticEnergy();
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G4Material* aMaterial = aTrack.GetMaterial();
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G4double MeanFreePath;
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G4bool isOutRange;
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if (GammaEnergy > HighestEnergyLimit || GammaEnergy < LowestEnergyLimit)
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MeanFreePath = DBL_MAX;
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else
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MeanFreePath = (*theMeanFreePathTable)(aMaterial->GetIndex())->
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GetValue(GammaEnergy, isOutRange);
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return MeanFreePath;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4VParticleChange* G4ComptonScattering52::PostStepDoIt(const G4Track& aTrack,
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const G4Step& aStep)
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//
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// The scattered gamma energy is sampled according to Klein - Nishina formula.
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// The random number techniques of Butcher & Messel are used
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// (Nuc Phys 20(1960),15).
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// GEANT4 internal units
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//
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// Note : Effects due to binding of atomic electrons are negliged.
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{
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aParticleChange.Initialize(aTrack);
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const G4DynamicParticle* aDynamicGamma = aTrack.GetDynamicParticle();
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G4double GammaEnergy0 = aDynamicGamma->GetKineticEnergy();
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G4double E0_m = GammaEnergy0 / electron_mass_c2 ;
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G4ParticleMomentum GammaDirection0 = aDynamicGamma->GetMomentumDirection();
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//
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// sample the energy rate of the scattered gamma
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//
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G4double epsilon, epsilonsq, onecost, sint2, greject ;
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G4double epsilon0 = 1./(1. + 2*E0_m) , epsilon0sq = epsilon0*epsilon0;
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G4double alpha1 = - log(epsilon0) , alpha2 = 0.5*(1.- epsilon0sq);
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do {
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if ( alpha1/(alpha1+alpha2) > G4UniformRand() )
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{ epsilon = exp(-alpha1*G4UniformRand()); // epsilon0**r
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epsilonsq = epsilon*epsilon; }
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else {
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epsilonsq = epsilon0sq + (1.- epsilon0sq)*G4UniformRand();
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epsilon = sqrt(epsilonsq);
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};
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onecost = (1.- epsilon)/(epsilon*E0_m);
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sint2 = onecost*(2.-onecost);
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greject = 1. - epsilon*sint2/(1.+ epsilonsq);
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} while (greject < G4UniformRand());
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//
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// scattered gamma angles. ( Z - axis along the parent gamma)
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//
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G4double cosTeta = 1. - onecost , sinTeta = sqrt (sint2);
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G4double Phi = twopi * G4UniformRand();
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G4double dirx = sinTeta*cos(Phi), diry = sinTeta*sin(Phi), dirz = cosTeta;
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//
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// update G4VParticleChange for the scattered gamma
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//
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G4ThreeVector GammaDirection1 ( dirx,diry,dirz );
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GammaDirection1.rotateUz(GammaDirection0);
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aParticleChange.ProposeMomentumDirection( GammaDirection1 );
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G4double GammaEnergy1 = epsilon*GammaEnergy0;
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G4double localEnergyDeposit = 0.;
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if (GammaEnergy1 > fminimalEnergy)
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{
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aParticleChange.ProposeEnergy( GammaEnergy1 );
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}
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else
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{
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localEnergyDeposit += GammaEnergy1;
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aParticleChange.ProposeEnergy(0.) ;
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aParticleChange.ProposeTrackStatus(fStopAndKill);
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}
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//
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// kinematic of the scattered electron
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//
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G4double ElecKineEnergy = GammaEnergy0 - GammaEnergy1;
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if (ElecKineEnergy > fminimalEnergy)
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{
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G4double ElecMomentum = sqrt(ElecKineEnergy*
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(ElecKineEnergy+2.*electron_mass_c2));
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G4ThreeVector ElecDirection (
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(GammaEnergy0*GammaDirection0 - GammaEnergy1*GammaDirection1)
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*(1./ElecMomentum) );
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// create G4DynamicParticle object for the electron.
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G4DynamicParticle* aElectron= new G4DynamicParticle(
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G4Electron::Electron(),ElecDirection,ElecKineEnergy);
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aParticleChange.SetNumberOfSecondaries(1);
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aParticleChange.AddSecondary( aElectron );
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}
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else
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{
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aParticleChange.SetNumberOfSecondaries(0);
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localEnergyDeposit += ElecKineEnergy;
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}
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aParticleChange.ProposeLocalEnergyDeposit (localEnergyDeposit);
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// Reset NbOfInteractionLengthLeft and return aParticleChange
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return G4VDiscreteProcess::PostStepDoIt( aTrack, aStep);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4bool G4ComptonScattering52::StorePhysicsTable(const G4ParticleDefinition* particle,
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const G4String& directory,
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G4bool ascii)
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{
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G4String filename;
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// store cross section table
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filename = GetPhysicsTableFileName(particle,directory,"CrossSection",ascii);
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if ( !theCrossSectionTable->StorePhysicsTable(filename, ascii) ){
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G4cout << " FAIL theCrossSectionTable->StorePhysicsTable in " << filename
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<< G4endl;
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return false;
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}
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// store mean free path table
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filename = GetPhysicsTableFileName(particle,directory,"MeanFreePath",ascii);
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if ( !theMeanFreePathTable->StorePhysicsTable(filename, ascii) ){
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G4cout << " FAIL theMeanFreePathTable->StorePhysicsTable in " << filename
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<< G4endl;
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return false;
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}
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G4cout << GetProcessName() << " for " << particle->GetParticleName()
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<< ": Success to store the PhysicsTables in "
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<< directory << G4endl;
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return true;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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/*
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G4bool G4ComptonScattering52::RetrievePhysicsTable(const G4ParticleDefinition* particle,
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const G4String& directory,
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G4bool ascii)
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{
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// delete theCrossSectionTable and theMeanFreePathTable
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if (theCrossSectionTable != 0) {
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theCrossSectionTable->clearAndDestroy();
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delete theCrossSectionTable;
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}
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if (theMeanFreePathTable != 0) {
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theMeanFreePathTable->clearAndDestroy();
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delete theMeanFreePathTable;
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}
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G4String filename;
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// retreive cross section table
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filename = GetPhysicsTableFileName(particle,directory,"CrossSection",ascii);
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theCrossSectionTable = new G4PhysicsTable(G4Element::GetNumberOfElements());
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if ( !G4PhysicsTableHelper::RetrievePhysicsTable(filename, ascii) ){
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G4cout << " FAIL theCrossSectionTable->RetrievePhysicsTable in " << filename
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<< G4endl;
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return false;
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}
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// retreive mean free path table
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filename = GetPhysicsTableFileName(particle,directory,"MeanFreePath",ascii);
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theMeanFreePathTable = new G4PhysicsTable(G4Material::GetNumberOfMaterials());
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if ( !G4PhysicsTableHelper::RetrievePhysicsTable(filename, ascii) ){
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G4cout << " FAIL theMeanFreePathTable->RetrievePhysicsTable in " << filename
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<< G4endl;
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return false;
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}
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G4cout << GetProcessName() << " for " << particle->GetParticleName()
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<< ": Success to retrieve the PhysicsTables from "
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<< directory << G4endl;
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return true;
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}
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*/
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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|
|
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void G4ComptonScattering52::PrintInfoDefinition()
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|
{
|
|
G4String comments = "Total cross sections from a parametrisation. ";
|
|
comments += "Good description from 10 KeV to (100/Z) GeV. \n";
|
|
comments += " Scattered gamma energy according Klein-Nishina.";
|
|
|
|
G4cout << G4endl << GetProcessName() << ": " << comments
|
|
<< "\n PhysicsTables from "
|
|
<< G4BestUnit(LowestEnergyLimit,"Energy")
|
|
<< " to " << G4BestUnit(HighestEnergyLimit,"Energy")
|
|
<< " in " << NumbBinTable << " bins. \n";
|
|
G4cout << " WARNING: This process is obsolete and will be soon removed"
|
|
<< G4endl;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|