Gabriele Cosmo
499 lines
18 KiB
C++
499 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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// -------------------------------------------------------------------
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//
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// GEANT4 Class header file
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//
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//
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// File name: G4BetheBlochModel
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//
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// Author: Vladimir Ivanchenko on base of Laszlo Urban code
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//
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// Creation date: 03.01.2002
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//
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// Modifications:
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//
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// 04-12-02 Fix problem of G4DynamicParticle constructor (V.Ivanchenko)
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// 23-12-02 Change interface in order to move to cut per region (V.Ivanchenko)
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// 27-01-03 Make models region aware (V.Ivanchenko)
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// 13-02-03 Add name (V.Ivanchenko)
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// 24-03-05 Add G4EmCorrections (V.Ivanchenko)
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// 11-04-05 Major optimisation of internal interfaces (V.Ivanchenko)
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// 11-02-06 ComputeCrossSectionPerElectron, ComputeCrossSectionPerAtom (mma)
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// 12-02-06 move G4LossTableManager::Instance()->EmCorrections()
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// in constructor (mma)
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// 12-08-08 Added methods GetParticleCharge, GetChargeSquareRatio,
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// CorrectionsAlongStep needed for ions(V.Ivanchenko)
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//
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// -------------------------------------------------------------------
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//
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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#include "G4BetheBlochModel.hh"
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#include "Randomize.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4SystemOfUnits.hh"
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#include "G4NistManager.hh"
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#include "G4Electron.hh"
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#include "G4LossTableManager.hh"
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#include "G4EmCorrections.hh"
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#include "G4EmParameters.hh"
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#include "G4ParticleChangeForLoss.hh"
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#include "G4ICRU90StoppingData.hh"
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#include "G4Log.hh"
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#include "G4DeltaAngle.hh"
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#include <vector>
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4BetheBlochModel::G4BetheBlochModel(const G4ParticleDefinition*,
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const G4String& nam)
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: G4VEmModel(nam),
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twoln10(2.0*G4Log(10.0)),
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fAlphaTlimit(1*CLHEP::GeV),
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fProtonTlimit(10*CLHEP::GeV)
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{
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theElectron = G4Electron::Electron();
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corr = G4LossTableManager::Instance()->EmCorrections();
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nist = G4NistManager::Instance();
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SetLowEnergyLimit(2.0*CLHEP::MeV);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4BetheBlochModel::~G4BetheBlochModel() = default;
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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void G4BetheBlochModel::Initialise(const G4ParticleDefinition* p,
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const G4DataVector&)
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{
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if(p != particle) { SetupParameters(p); }
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// always false before the run
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SetDeexcitationFlag(false);
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// initialisation once
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if(nullptr == fParticleChange) {
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const G4String& pname = particle->GetParticleName();
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if(G4EmParameters::Instance()->UseICRU90Data() &&
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(pname == "proton" || pname == "GenericIon" || pname == "alpha")) {
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fICRU90 = nist->GetICRU90StoppingData();
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}
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if(particle->GetPDGCharge() > CLHEP::eplus ||
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pname == "GenericIon") { isIon = true; }
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if(pname == "alpha") { isAlpha = true; }
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fParticleChange = GetParticleChangeForLoss();
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if(UseAngularGeneratorFlag() && nullptr == GetAngularDistribution()) {
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SetAngularDistribution(new G4DeltaAngle());
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}
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}
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// initialisation for each new run
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if(IsMaster() && nullptr != fICRU90) {
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fICRU90->Initialise();
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4BetheBlochModel::GetChargeSquareRatio(const G4ParticleDefinition* p,
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const G4Material* mat,
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G4double kinEnergy)
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{
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// this method is called only for ions, so no check if it is an ion
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if(isAlpha) { return 1.0; }
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chargeSquare = corr->EffectiveChargeSquareRatio(p, mat, kinEnergy);
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return chargeSquare;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4BetheBlochModel::GetParticleCharge(const G4ParticleDefinition* p,
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const G4Material* mat,
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G4double kineticEnergy)
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{
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// this method is called only for ions, so no check if it is an ion
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return corr->GetParticleCharge(p, mat, kineticEnergy);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4BetheBlochModel::SetupParameters(const G4ParticleDefinition* p)
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{
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particle = p;
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mass = particle->GetPDGMass();
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spin = particle->GetPDGSpin();
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G4double q = particle->GetPDGCharge()*inveplus;
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isIon = (!isAlpha && q > 1.1);
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chargeSquare = q*q;
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ratio = electron_mass_c2/mass;
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constexpr G4double aMag = 1./(0.5*eplus*CLHEP::hbar_Planck*CLHEP::c_squared);
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G4double magmom = particle->GetPDGMagneticMoment()*mass*aMag;
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magMoment2 = magmom*magmom - 1.0;
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formfact = 0.0;
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tlimit = DBL_MAX;
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if(particle->GetLeptonNumber() == 0) {
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G4double x = 0.8426*CLHEP::GeV;
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if(spin == 0.0 && mass < CLHEP::GeV) { x = 0.736*CLHEP::GeV; }
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else if (mass > CLHEP::GeV) {
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G4int iz = G4lrint(std::abs(q));
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if(iz > 1) { x /= nist->GetA27(iz); }
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}
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formfact = 2.0*CLHEP::electron_mass_c2/(x*x);
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tlimit = 2.0/formfact;
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4BetheBlochModel::MinEnergyCut(const G4ParticleDefinition*,
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const G4MaterialCutsCouple* couple)
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{
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return couple->GetMaterial()->GetIonisation()->GetMeanExcitationEnergy();
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double
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G4BetheBlochModel::ComputeCrossSectionPerElectron(const G4ParticleDefinition* p,
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G4double kineticEnergy,
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G4double cut,
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G4double maxKinEnergy)
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{
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G4double cross = 0.0;
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const G4double tmax = MaxSecondaryEnergy(p, kineticEnergy);
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const G4double cutEnergy = std::min(std::min(cut,tmax), tlimit);
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const G4double maxEnergy = std::min(tmax, maxKinEnergy);
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if(cutEnergy < maxEnergy) {
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G4double totEnergy = kineticEnergy + mass;
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G4double energy2 = totEnergy*totEnergy;
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G4double beta2 = kineticEnergy*(kineticEnergy + 2.0*mass)/energy2;
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cross = (maxEnergy - cutEnergy)/(cutEnergy*maxEnergy)
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- beta2*G4Log(maxEnergy/cutEnergy)/tmax;
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// +term for spin=1/2 particle
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if( 0.0 < spin ) { cross += 0.5*(maxEnergy - cutEnergy)/energy2; }
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cross *= CLHEP::twopi_mc2_rcl2*chargeSquare/beta2;
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}
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// G4cout << "BB: e= " << kineticEnergy << " tmin= " << cutEnergy
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// << " tmax= " << tmax << " cross= " << cross << G4endl;
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return cross;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4BetheBlochModel::ComputeCrossSectionPerAtom(
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const G4ParticleDefinition* p,
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G4double kinEnergy,
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G4double Z, G4double,
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G4double cutEnergy,
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G4double maxEnergy)
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{
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return Z*ComputeCrossSectionPerElectron(p,kinEnergy,cutEnergy,maxEnergy);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4BetheBlochModel::CrossSectionPerVolume(
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const G4Material* mat,
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const G4ParticleDefinition* p,
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G4double kinEnergy,
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G4double cutEnergy,
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G4double maxEnergy)
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{
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G4double sigma = mat->GetElectronDensity()
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*ComputeCrossSectionPerElectron(p,kinEnergy,cutEnergy,maxEnergy);
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if(isAlpha) {
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sigma *= corr->EffectiveChargeSquareRatio(p,mat,kinEnergy)/chargeSquare;
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}
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return sigma;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4BetheBlochModel::ComputeDEDXPerVolume(const G4Material* material,
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const G4ParticleDefinition* p,
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G4double kineticEnergy,
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G4double cut)
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{
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const G4double tmax = MaxSecondaryEnergy(p, kineticEnergy);
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// projectile formfactor limit energy loss
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const G4double cutEnergy = std::min(std::min(cut,tmax), tlimit);
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G4double tau = kineticEnergy/mass;
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G4double gam = tau + 1.0;
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G4double bg2 = tau * (tau+2.0);
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G4double beta2 = bg2/(gam*gam);
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G4double xc = cutEnergy/tmax;
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G4double eexc = material->GetIonisation()->GetMeanExcitationEnergy();
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G4double eexc2 = eexc*eexc;
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G4double eDensity = material->GetElectronDensity();
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// added ICRU90 stopping data for limited list of materials
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/*
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G4cout << "### DEDX ICRI90:" << (nullptr != fICRU90)
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<< " Ekin=" << kineticEnergy
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<< " " << p->GetParticleName()
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<< " q2=" << chargeSquare
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<< " inside " << material->GetName() << G4endl;
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*/
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if(nullptr != fICRU90 && kineticEnergy < fProtonTlimit) {
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if(material != currentMaterial) {
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currentMaterial = material;
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baseMaterial = material->GetBaseMaterial()
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? material->GetBaseMaterial() : material;
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iICRU90 = fICRU90->GetIndex(baseMaterial);
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}
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if(iICRU90 >= 0) {
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G4double dedx = 0.0;
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// only for alpha
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if(isAlpha) {
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if(kineticEnergy <= fAlphaTlimit) {
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dedx = fICRU90->GetElectronicDEDXforAlpha(iICRU90, kineticEnergy);
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} else {
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const G4double e = kineticEnergy*CLHEP::proton_mass_c2/mass;
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dedx = fICRU90->GetElectronicDEDXforProton(iICRU90, e)*chargeSquare;
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}
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} else {
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dedx = fICRU90->GetElectronicDEDXforProton(iICRU90, kineticEnergy)
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*chargeSquare;
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}
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dedx *= material->GetDensity();
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if(cutEnergy < tmax) {
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dedx += (G4Log(xc) + (1.0 - xc)*beta2)*CLHEP::twopi_mc2_rcl2
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*(eDensity*chargeSquare/beta2);
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}
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//G4cout << " iICRU90=" << iICRU90 << " dedx=" << dedx << G4endl;
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if(dedx > 0.0) { return dedx; }
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}
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}
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// general Bethe-Bloch formula
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G4double dedx = G4Log(2.0*CLHEP::electron_mass_c2*bg2*cutEnergy/eexc2)
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- (1.0 + xc)*beta2;
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if(0.0 < spin) {
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G4double del = 0.5*cutEnergy/(kineticEnergy + mass);
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dedx += del*del;
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}
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// density correction
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G4double x = G4Log(bg2)/twoln10;
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dedx -= material->GetIonisation()->DensityCorrection(x);
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// shell correction
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dedx -= 2.0*corr->ShellCorrection(p,material,kineticEnergy);
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// now compute the total ionization loss
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dedx *= CLHEP::twopi_mc2_rcl2*chargeSquare*eDensity/beta2;
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//High order correction different for hadrons and ions
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if(isIon) {
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dedx += corr->IonBarkasCorrection(p,material,kineticEnergy);
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} else {
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dedx += corr->HighOrderCorrections(p,material,kineticEnergy,cutEnergy);
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}
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dedx = std::max(dedx, 0.0);
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/*
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G4cout << "E(MeV)= " << kineticEnergy/CLHEP::MeV << " dedx= " << dedx
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<< " " << material->GetName() << G4endl;
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*/
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return dedx;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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void G4BetheBlochModel::CorrectionsAlongStep(const G4MaterialCutsCouple* couple,
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const G4DynamicParticle* dp,
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const G4double& /*length*/,
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G4double& eloss)
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{
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// no correction for alpha
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if(isAlpha) { return; }
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// no correction at the last step or at small step
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const G4double preKinEnergy = dp->GetKineticEnergy();
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if(eloss >= preKinEnergy || eloss < preKinEnergy*0.05) { return; }
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// corrections for all charged particles with Q > 1
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const G4ParticleDefinition* p = dp->GetDefinition();
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if(p != particle) { SetupParameters(p); }
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if(!isIon) { return; }
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// effective energy and charge at a step
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const G4double e = std::max(preKinEnergy - eloss*0.5, preKinEnergy*0.5);
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const G4Material* mat = couple->GetMaterial();
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const G4double q20 = corr->EffectiveChargeSquareRatio(p, mat, preKinEnergy);
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const G4double q2 = corr->EffectiveChargeSquareRatio(p, mat, e);
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const G4double qfactor = q2/q20;
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/*
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G4cout << "G4BetheBlochModel::CorrectionsAlongStep: Epre(MeV)="
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<< preKinEnergy << " Eeff(MeV)=" << e
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<< " eloss=" << eloss << " elossnew=" << eloss*qfactor
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<< " qfactor=" << qfactor << " Qpre=" << q20
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<< p->GetParticleName() <<G4endl;
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*/
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eloss *= qfactor;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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void G4BetheBlochModel::SampleSecondaries(std::vector<G4DynamicParticle*>* vdp,
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const G4MaterialCutsCouple* couple,
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const G4DynamicParticle* dp,
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G4double cut,
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G4double maxEnergy)
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{
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G4double kinEnergy = dp->GetKineticEnergy();
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const G4double tmax = MaxSecondaryEnergy(dp->GetDefinition(), kinEnergy);
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const G4double minKinEnergy = std::min(cut, tmax);
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const G4double maxKinEnergy = std::min(maxEnergy, tmax);
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if(minKinEnergy >= maxKinEnergy) { return; }
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//G4cout << "G4BetheBlochModel::SampleSecondaries Emin= " << minKinEnergy
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// << " Emax= " << maxKinEnergy << G4endl;
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const G4double totEnergy = kinEnergy + mass;
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const G4double etot2 = totEnergy*totEnergy;
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const G4double beta2 = kinEnergy*(kinEnergy + 2.0*mass)/etot2;
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G4double deltaKinEnergy, f;
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G4double f1 = 0.0;
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G4double fmax = 1.0;
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if( 0.0 < spin ) { fmax += 0.5*maxKinEnergy*maxKinEnergy/etot2; }
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CLHEP::HepRandomEngine* rndmEngineMod = G4Random::getTheEngine();
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G4double rndm[2];
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// sampling without nuclear size effect
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do {
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rndmEngineMod->flatArray(2, rndm);
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deltaKinEnergy = minKinEnergy*maxKinEnergy
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/(minKinEnergy*(1.0 - rndm[0]) + maxKinEnergy*rndm[0]);
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f = 1.0 - beta2*deltaKinEnergy/tmax;
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if( 0.0 < spin ) {
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f1 = 0.5*deltaKinEnergy*deltaKinEnergy/etot2;
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f += f1;
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}
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// Loop checking, 03-Aug-2015, Vladimir Ivanchenko
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} while( fmax*rndm[1] > f);
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// projectile formfactor - suppresion of high energy
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// delta-electron production at high energy
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G4double x = formfact*deltaKinEnergy;
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if(x > 1.e-6) {
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G4double x1 = 1.0 + x;
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G4double grej = 1.0/(x1*x1);
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if( 0.0 < spin ) {
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G4double x2 = 0.5*electron_mass_c2*deltaKinEnergy/(mass*mass);
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grej *= (1.0 + magMoment2*(x2 - f1/f)/(1.0 + x2));
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}
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if(grej > 1.1) {
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G4cout << "### G4BetheBlochModel WARNING: grej= " << grej
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<< " " << dp->GetDefinition()->GetParticleName()
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<< " Ekin(MeV)= " << kinEnergy
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<< " delEkin(MeV)= " << deltaKinEnergy
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<< G4endl;
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}
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if(rndmEngineMod->flat() > grej) { return; }
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}
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G4ThreeVector deltaDirection;
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if(UseAngularGeneratorFlag()) {
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const G4Material* mat = couple->GetMaterial();
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deltaDirection =
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GetAngularDistribution()->SampleDirection(dp, deltaKinEnergy,
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SelectRandomAtomNumber(mat),
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mat);
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} else {
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G4double deltaMomentum =
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std::sqrt(deltaKinEnergy * (deltaKinEnergy + 2.0*electron_mass_c2));
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G4double cost = deltaKinEnergy * (totEnergy + electron_mass_c2) /
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(deltaMomentum * dp->GetTotalMomentum());
|
|
cost = std::min(cost, 1.0);
|
|
const G4double sint = std::sqrt((1.0 - cost)*(1.0 + cost));
|
|
const G4double phi = twopi*rndmEngineMod->flat();
|
|
|
|
deltaDirection.set(sint*std::cos(phi),sint*std::sin(phi), cost) ;
|
|
deltaDirection.rotateUz(dp->GetMomentumDirection());
|
|
}
|
|
/*
|
|
G4cout << "### G4BetheBlochModel "
|
|
<< dp->GetDefinition()->GetParticleName()
|
|
<< " Ekin(MeV)= " << kinEnergy
|
|
<< " delEkin(MeV)= " << deltaKinEnergy
|
|
<< " tmin(MeV)= " << minKinEnergy
|
|
<< " tmax(MeV)= " << maxKinEnergy
|
|
<< " dir= " << dp->GetMomentumDirection()
|
|
<< " dirDelta= " << deltaDirection
|
|
<< G4endl;
|
|
*/
|
|
// create G4DynamicParticle object for delta ray
|
|
auto delta = new G4DynamicParticle(theElectron,deltaDirection,deltaKinEnergy);
|
|
|
|
vdp->push_back(delta);
|
|
|
|
// Change kinematics of primary particle
|
|
kinEnergy -= deltaKinEnergy;
|
|
G4ThreeVector finalP = dp->GetMomentum() - delta->GetMomentum();
|
|
finalP = finalP.unit();
|
|
|
|
fParticleChange->SetProposedKineticEnergy(kinEnergy);
|
|
fParticleChange->SetProposedMomentumDirection(finalP);
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|
|
|
G4double G4BetheBlochModel::MaxSecondaryEnergy(const G4ParticleDefinition* pd,
|
|
G4double kinEnergy)
|
|
{
|
|
// here particle type is checked for the case,
|
|
// when this model is shared between particles
|
|
if(pd != particle) { SetupParameters(pd); }
|
|
G4double tau = kinEnergy/mass;
|
|
return 2.0*CLHEP::electron_mass_c2*tau*(tau + 2.) /
|
|
(1. + 2.0*(tau + 1.)*ratio + ratio*ratio);
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|