Gabriele Cosmo
189 lines
6.1 KiB
C++
189 lines
6.1 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: G4mplIonisationModel.cc,v 1.3 2006/12/13 15:44:27 gunter Exp $
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// GEANT4 tag $Name: geant4-08-02 $
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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: G4mplIonisationModel
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//
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// Author: Vladimir Ivanchenko
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//
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// Creation date: 06.09.2005
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//
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// Modifications:
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//
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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 "G4mplIonisationModel.hh"
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#include "Randomize.hh"
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#include "G4LossTableManager.hh"
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#include "G4ParticleChangeForLoss.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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using namespace std;
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G4mplIonisationModel::G4mplIonisationModel(G4double mCharge,
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const G4String& nam)
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: G4VEmModel(nam),G4VEmFluctuationModel(nam),
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magCharge(mCharge),
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twoln10(2.0*log(10.0)),
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beta2low(0.0001),
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beta2lim(0.01),
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bg2lim(beta2lim*(1.0 + beta2lim))
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{
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nmpl = G4int(abs(magCharge)/68.0);
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if(nmpl > 6) nmpl = 6;
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else if(nmpl < 1) nmpl = 1;
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G4double x = 45.0*GeV*G4double(nmpl)/cm;
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factlow = x*x;
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chargeSquare = magCharge*magCharge;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4mplIonisationModel::~G4mplIonisationModel()
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{}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4mplIonisationModel::Initialise(const G4ParticleDefinition* p,
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const G4DataVector&)
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{
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monopole = p;
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mass = monopole->GetPDGMass();
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if(pParticleChange)
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fParticleChange = reinterpret_cast<G4ParticleChangeForLoss*>(pParticleChange);
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else
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fParticleChange = new G4ParticleChangeForLoss();
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4mplIonisationModel::ComputeDEDXPerVolume(const G4Material* material,
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const G4ParticleDefinition*,
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G4double kineticEnergy,
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G4double)
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{
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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 dedx0 = factlow*abs(beta2);
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if(beta2 > beta2low) {
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G4double b2 = beta2;
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if(beta2 < beta2lim) {
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beta2= beta2lim;
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bg2 = bg2lim;
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}
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G4double eexc = material->GetIonisation()->GetMeanExcitationEnergy();
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G4double cden = material->GetIonisation()->GetCdensity();
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G4double mden = material->GetIonisation()->GetMdensity();
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G4double aden = material->GetIonisation()->GetAdensity();
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G4double x0den = material->GetIonisation()->GetX0density();
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G4double x1den = material->GetIonisation()->GetX1density();
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G4double eDensity = material->GetElectronDensity();
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G4double dedx = 2.0*log(2.0*electron_mass_c2*bg2/eexc) - 1.0;
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G4double k = 0.406;
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if(nmpl > 1) k = 0.346;
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const G4double B[7] = { 0.0, 0.248, 0.672, 1.022, 1.243, 1.464, 1.685};
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dedx += k - B[nmpl];
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// density correction
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G4double x = log(bg2)/twoln10;
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if ( x >= x0den ) {
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dedx -= twoln10*x - cden ;
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if ( x < x1den ) dedx -= aden*pow((x1den-x),mden) ;
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}
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// now compute the total ionization loss
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if (dedx < 0.0) dedx = 0.0 ;
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dedx *= twopi_mc2_rcl2*chargeSquare*eDensity;
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// extrapolate between two formula
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if(beta2 < beta2lim) {
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x = log(dedx0) + log(dedx/dedx0)*log(b2/beta2low)/log(beta2lim/beta2low);
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dedx = exp(x);
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}
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dedx0 = dedx;
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}
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return dedx0;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4mplIonisationModel::SampleFluctuations(
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const G4Material* material,
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const G4DynamicParticle* dp,
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G4double& tmax,
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G4double& length,
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G4double& meanLoss)
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{
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G4double siga = Dispersion(material,dp,tmax,length);
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G4double loss = meanLoss;
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siga = sqrt(siga);
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G4double twomeanLoss = meanLoss + meanLoss;
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if(twomeanLoss < siga) {
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G4double x;
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do {
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loss = twomeanLoss*G4UniformRand();
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x = (loss - meanLoss)/siga;
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} while (1.0 - 0.5*x*x < G4UniformRand());
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} else {
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do {
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loss = G4RandGauss::shoot(meanLoss,siga);
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} while (0.0 > loss || loss > twomeanLoss);
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}
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//G4cout << "G4mplIonisationModel::SampleFluctuations: loss= " << loss
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//<< " siga= " << siga << G4endl;
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return loss;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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