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geant4/source/processes/electromagnetic/standard/include/G4eCoulombScatteringModel.hh
T
Gabriele Cosmo b79225fb37 Import Geant4 9.2.0 source tree
2016-06-09 15:58:43 +02:00

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//
// ********************************************************************
// * 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. *
// ********************************************************************
//
// $Id: G4eCoulombScatteringModel.hh,v 1.36 2008/08/04 08:49:09 vnivanch Exp $
// GEANT4 tag $Name: geant4-09-02 $
//
// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name: G4eCoulombScatteringModel
//
// Author: Vladimir Ivanchenko
//
// Creation date: 19.02.2006
//
// Modifications:
// 01.08.06 V.Ivanchenko extend upper limit of table to TeV and review the
// logic of building - only elements from G4ElementTable
// 08.08.06 V.Ivanchenko build internal table in ekin scale, introduce faclim
// 19.08.06 V.Ivanchenko add inline function ScreeningParameter and
// make some members protected
// 09.10.07 V.Ivanchenko reorganized methods, add cut dependence in scattering off e-
// 09.06.08 V.Ivanchenko add SelectIsotope and sampling of the recoil ion
//
// Class Description:
//
// Implementation of eCoulombScattering of pointlike charge particle
// on Atomic Nucleus for interval of scattering anles in Lab system
// thetaMin - ThetaMax, nucleus recoil is neglected.
// The model based on analysis of J.M.Fernandez-Varea et al.
// NIM B73(1993)447 originated from G.Wentzel Z.Phys. 40(1927)590 with
// screening parameter from H.A.Bethe Phys. Rev. 89 (1953) 1256.
//
// -------------------------------------------------------------------
//
#ifndef G4eCoulombScatteringModel_h
#define G4eCoulombScatteringModel_h 1
#include "G4VEmModel.hh"
#include "G4PhysicsTable.hh"
#include "G4NistManager.hh"
#include "globals.hh"
class G4ParticleChangeForGamma;
class G4ParticleDefinition;
class G4eCoulombScatteringModel : public G4VEmModel
{
public:
G4eCoulombScatteringModel(const G4String& nam = "eCoulombScattering");
virtual ~G4eCoulombScatteringModel();
virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&);
virtual G4double ComputeCrossSectionPerAtom(
const G4ParticleDefinition*,
G4double kinEnergy,
G4double Z,
G4double A,
G4double cut,
G4double emax);
virtual void SampleSecondaries(std::vector<G4DynamicParticle*>*,
const G4MaterialCutsCouple*,
const G4DynamicParticle*,
G4double tmin,
G4double maxEnergy);
inline void SetRecoilThreshold(G4double eth);
protected:
G4double CrossSectionPerAtom();
G4double SampleCosineTheta();
inline void DefineMaterial(const G4MaterialCutsCouple*);
inline void SetupParticle(const G4ParticleDefinition*);
inline void SetupKinematic(G4double kinEnergy, G4double cut);
inline void SetupTarget(G4double Z, G4double kinEnergy);
private:
void ComputeMaxElectronScattering(G4double cut);
// hide assignment operator
G4eCoulombScatteringModel & operator=(const G4eCoulombScatteringModel &right);
G4eCoulombScatteringModel(const G4eCoulombScatteringModel&);
protected:
const G4ParticleDefinition* theProton;
const G4ParticleDefinition* theElectron;
const G4ParticleDefinition* thePositron;
G4ParticleTable* theParticleTable;
G4ParticleChangeForGamma* fParticleChange;
G4NistManager* fNistManager;
const G4DataVector* currentCuts;
const G4MaterialCutsCouple* currentCouple;
const G4Material* currentMaterial;
const G4Element* currentElement;
G4int currentMaterialIndex;
G4double coeff;
G4double constn;
G4double cosThetaMin;
G4double cosThetaMax;
G4double cosTetMinNuc;
G4double cosTetMaxNuc;
G4double cosTetMaxNuc2;
G4double cosTetMaxElec;
G4double cosTetMaxElec2;
G4double q2Limit;
G4double recoilThreshold;
G4double elecXSection;
G4double nucXSection;
G4double ecut;
// projectile
const G4ParticleDefinition* particle;
G4double chargeSquare;
G4double spin;
G4double mass;
G4double tkin;
G4double mom2;
G4double invbeta2;
G4double etag;
G4double lowEnergyLimit;
// target
G4double targetZ;
G4double screenZ;
G4double formfactA;
G4int idxelm;
private:
G4double a0;
G4double alpha2;
G4double faclim;
G4double FF[100];
G4bool isInitialised;
};
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
inline
void G4eCoulombScatteringModel::DefineMaterial(const G4MaterialCutsCouple* cup)
{
if(cup != currentCouple) {
currentCouple = cup;
currentMaterial = cup->GetMaterial();
currentMaterialIndex = currentCouple->GetIndex();
}
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
inline
void G4eCoulombScatteringModel::SetupParticle(const G4ParticleDefinition* p)
{
// Initialise mass and charge
if(p != particle) {
particle = p;
mass = particle->GetPDGMass();
spin = particle->GetPDGSpin();
G4double q = particle->GetPDGCharge()/eplus;
chargeSquare = q*q;
tkin = 0.0;
lowEnergyLimit = keV*mass/electron_mass_c2;
}
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
inline void G4eCoulombScatteringModel::SetupKinematic(G4double ekin,
G4double cut)
{
if(ekin != tkin || ecut != cut) {
tkin = ekin;
mom2 = tkin*(tkin + 2.0*mass);
invbeta2 = 1.0 + mass*mass/mom2;
cosTetMinNuc = cosThetaMin;
cosTetMaxNuc = cosThetaMax;
if(ekin <= 10.*cut && mass < MeV && cosThetaMin < 1.0) {
cosTetMinNuc = ekin*(cosThetaMin + 1.0)/(10.*cut) - 1.0;
}
ComputeMaxElectronScattering(cut);
}
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
inline void G4eCoulombScatteringModel::SetupTarget(G4double Z, G4double e)
{
if(Z != targetZ || e != etag) {
etag = e;
targetZ = Z;
G4int iz= G4int(Z);
if(iz > 99) iz = 99;
G4double x = fNistManager->GetZ13(iz);
screenZ = a0*x*x/mom2;
if(iz > 1) screenZ *=(1.13 + 3.76*invbeta2*Z*Z*chargeSquare*alpha2);
//screenZ = a0*x*x*(1.13 + 3.76*Z*Z*chargeSquare*alpha2)/mom2;
// A.V. Butkevich et al., NIM A 488 (2002) 282
formfactA = FF[iz];
if(formfactA == 0.0) {
x = fNistManager->GetA27(iz);
formfactA = constn*x*x;
FF[iz] = formfactA;
}
formfactA *= mom2;
cosTetMaxNuc2 = cosTetMaxNuc;
if(particle == theProton && 1 == iz && cosTetMaxNuc2 < 0.0) {
cosTetMaxNuc2 = 0.0;
}
/*
G4double ee = 10.*eV*Z;
if(1 == iz) ee *= 2.0;
G4double z = std::min(cosTetMaxElec, 1.0 - std::max(ecut,ee)*amu_c2
*fNistManager->GetAtomicMassAmu(iz)/mom2);
cosTetMaxElec2 = std::max(cosTetMaxNuc2, z);
*/
cosTetMaxElec2 = cosTetMaxElec;
}
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
inline void G4eCoulombScatteringModel::SetRecoilThreshold(G4double eth)
{
recoilThreshold = eth;
}
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
#endif
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