Gabriele Cosmo
1139 lines
38 KiB
C++
1139 lines
38 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: $
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// GEANT4 tag $Name: $
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//
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// -------------------------------------------------------------------
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//
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// GEANT4 Class file
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//
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//
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// File name: G4UrbanMscModel
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//
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// Author: Laszlo Urban
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//
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// Creation date: 19.02.2013
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//
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// Created from G4UrbanMscModel96
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//
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// New parametrization for theta0
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// Correction for very small step length
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//
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// Class Description:
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//
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// Implementation of the model of multiple scattering based on
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// H.W.Lewis Phys Rev 78 (1950) 526 and others
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// -------------------------------------------------------------------
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// In its present form the model can be used for simulation
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// of the e-/e+ multiple scattering
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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 "G4UrbanMscModel.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4SystemOfUnits.hh"
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#include "Randomize.hh"
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#include "G4Electron.hh"
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#include "G4LossTableManager.hh"
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#include "G4ParticleChangeForMSC.hh"
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#include "G4Poisson.hh"
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#include "G4Pow.hh"
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#include "globals.hh"
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#include "G4Log.hh"
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#include "G4Exp.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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using namespace std;
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static const G4double c_highland = 13.6*CLHEP::MeV ;
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static const G4double Tlim = 10.*CLHEP::MeV;
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static const G4double sigmafactor =
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CLHEP::twopi*CLHEP::classic_electr_radius*CLHEP::classic_electr_radius;
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static const G4double epsfactor = 2.*CLHEP::electron_mass_c2*
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CLHEP::electron_mass_c2*CLHEP::Bohr_radius*CLHEP::Bohr_radius
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/(CLHEP::hbarc*CLHEP::hbarc);
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static const G4double beta2lim = Tlim*(Tlim+2.*CLHEP::electron_mass_c2)/
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((Tlim+CLHEP::electron_mass_c2)*(Tlim+CLHEP::electron_mass_c2));
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static const G4double bg2lim = Tlim*(Tlim+2.*CLHEP::electron_mass_c2)/
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(CLHEP::electron_mass_c2*CLHEP::electron_mass_c2);
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static const G4double sig0[15] = {
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0.2672*CLHEP::barn, 0.5922*CLHEP::barn, 2.653*CLHEP::barn, 6.235*CLHEP::barn,
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11.69*CLHEP::barn , 13.24*CLHEP::barn , 16.12*CLHEP::barn, 23.00*CLHEP::barn,
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35.13*CLHEP::barn , 39.95*CLHEP::barn , 50.85*CLHEP::barn, 67.19*CLHEP::barn,
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91.15*CLHEP::barn , 104.4*CLHEP::barn , 113.1*CLHEP::barn};
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static const G4double Tdat[22] = {
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100*CLHEP::eV, 200*CLHEP::eV, 400*CLHEP::eV, 700*CLHEP::eV,
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1*CLHEP::keV, 2*CLHEP::keV, 4*CLHEP::keV, 7*CLHEP::keV,
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10*CLHEP::keV, 20*CLHEP::keV, 40*CLHEP::keV, 70*CLHEP::keV,
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100*CLHEP::keV, 200*CLHEP::keV, 400*CLHEP::keV, 700*CLHEP::keV,
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1*CLHEP::MeV, 2*CLHEP::MeV, 4*CLHEP::MeV, 7*CLHEP::MeV,
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10*CLHEP::MeV, 20*CLHEP::MeV};
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4UrbanMscModel::G4UrbanMscModel(const G4String& nam)
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: G4VMscModel(nam)
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{
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masslimite = 0.6*MeV;
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lambdalimit = 1.*mm;
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fr = 0.02;
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taubig = 8.0;
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tausmall = 1.e-16;
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taulim = 1.e-6;
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currentTau = taulim;
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tlimitminfix = 0.01*nm;
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tlimitminfix2 = 1.*nm;
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stepmin = tlimitminfix;
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smallstep = 1.e10;
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currentRange = 0. ;
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rangeinit = 0.;
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tlimit = 1.e10*mm;
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tlimitmin = 10.*tlimitminfix;
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tgeom = 1.e50*mm;
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geombig = 1.e50*mm;
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geommin = 1.e-3*mm;
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geomlimit = geombig;
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presafety = 0.*mm;
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y = 0.;
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Zold = 0.;
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Zeff = 1.;
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Z2 = 1.;
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Z23 = 1.;
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lnZ = 0.;
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coeffth1 = 0.;
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coeffth2 = 0.;
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coeffc1 = 0.;
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coeffc2 = 0.;
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coeffc3 = 0.;
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coeffc4 = 0.;
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theta0max = pi/6.;
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rellossmax = 0.50;
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third = 1./3.;
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particle = 0;
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theManager = G4LossTableManager::Instance();
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firstStep = true;
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inside = false;
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insideskin = false;
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skindepth = skin*stepmin;
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mass = proton_mass_c2;
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charge = ChargeSquare = 1.0;
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currentKinEnergy = currentRadLength = lambda0 = lambdaeff = tPathLength
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= zPathLength = par1 = par2 = par3 = 0;
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currentMaterialIndex = -1;
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fParticleChange = 0;
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couple = 0;
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SetSampleZ(true);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4UrbanMscModel::~G4UrbanMscModel()
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{}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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void G4UrbanMscModel::Initialise(const G4ParticleDefinition* p,
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const G4DataVector&)
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{
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skindepth = skin*stepmin;
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// trackID = -1;
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// set values of some data members
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SetParticle(p);
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/*
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if(p->GetPDGMass() > MeV) {
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G4cout << "### WARNING: G4UrbanMscModel model is used for "
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<< p->GetParticleName() << " !!! " << G4endl;
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G4cout << "### This model should be used only for e+-"
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<< G4endl;
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}
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*/
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fParticleChange = GetParticleChangeForMSC(p);
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//samplez = true;
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//G4cout << "### G4UrbanMscModel::Initialise done!" << G4endl;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4UrbanMscModel::ComputeCrossSectionPerAtom(
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const G4ParticleDefinition* part,
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G4double KineticEnergy,
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G4double AtomicNumber,G4double,
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G4double, G4double)
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{
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static const G4double epsmin = 1.e-4 , epsmax = 1.e10;
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static const G4double Zdat[15] = { 4., 6., 13., 20., 26., 29., 32., 38.,47.,
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50., 56., 64., 74., 79., 82. };
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// corr. factors for e-/e+ lambda for T <= Tlim
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static const G4double celectron[15][22] =
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{{1.125,1.072,1.051,1.047,1.047,1.050,1.052,1.054,
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1.054,1.057,1.062,1.069,1.075,1.090,1.105,1.111,
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1.112,1.108,1.100,1.093,1.089,1.087 },
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{1.408,1.246,1.143,1.096,1.077,1.059,1.053,1.051,
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1.052,1.053,1.058,1.065,1.072,1.087,1.101,1.108,
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1.109,1.105,1.097,1.090,1.086,1.082 },
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{2.833,2.268,1.861,1.612,1.486,1.309,1.204,1.156,
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1.136,1.114,1.106,1.106,1.109,1.119,1.129,1.132,
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1.131,1.124,1.113,1.104,1.099,1.098 },
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{3.879,3.016,2.380,2.007,1.818,1.535,1.340,1.236,
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1.190,1.133,1.107,1.099,1.098,1.103,1.110,1.113,
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1.112,1.105,1.096,1.089,1.085,1.098 },
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{6.937,4.330,2.886,2.256,1.987,1.628,1.395,1.265,
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1.203,1.122,1.080,1.065,1.061,1.063,1.070,1.073,
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1.073,1.070,1.064,1.059,1.056,1.056 },
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{9.616,5.708,3.424,2.551,2.204,1.762,1.485,1.330,
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1.256,1.155,1.099,1.077,1.070,1.068,1.072,1.074,
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1.074,1.070,1.063,1.059,1.056,1.052 },
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{11.72,6.364,3.811,2.806,2.401,1.884,1.564,1.386,
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1.300,1.180,1.112,1.082,1.073,1.066,1.068,1.069,
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1.068,1.064,1.059,1.054,1.051,1.050 },
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{18.08,8.601,4.569,3.183,2.662,2.025,1.646,1.439,
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1.339,1.195,1.108,1.068,1.053,1.040,1.039,1.039,
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1.039,1.037,1.034,1.031,1.030,1.036 },
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{18.22,10.48,5.333,3.713,3.115,2.367,1.898,1.631,
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1.498,1.301,1.171,1.105,1.077,1.048,1.036,1.033,
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1.031,1.028,1.024,1.022,1.021,1.024 },
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{14.14,10.65,5.710,3.929,3.266,2.453,1.951,1.669,
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1.528,1.319,1.178,1.106,1.075,1.040,1.027,1.022,
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1.020,1.017,1.015,1.013,1.013,1.020 },
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{14.11,11.73,6.312,4.240,3.478,2.566,2.022,1.720,
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1.569,1.342,1.186,1.102,1.065,1.022,1.003,0.997,
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0.995,0.993,0.993,0.993,0.993,1.011 },
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{22.76,20.01,8.835,5.287,4.144,2.901,2.219,1.855,
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1.677,1.410,1.224,1.121,1.073,1.014,0.986,0.976,
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0.974,0.972,0.973,0.974,0.975,0.987 },
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{50.77,40.85,14.13,7.184,5.284,3.435,2.520,2.059,
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1.837,1.512,1.283,1.153,1.091,1.010,0.969,0.954,
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0.950,0.947,0.949,0.952,0.954,0.963 },
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{65.87,59.06,15.87,7.570,5.567,3.650,2.682,2.182,
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1.939,1.579,1.325,1.178,1.108,1.014,0.965,0.947,
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0.941,0.938,0.940,0.944,0.946,0.954 },
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{55.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239,
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1.985,1.609,1.343,1.188,1.113,1.013,0.960,0.939,
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0.933,0.930,0.933,0.936,0.939,0.949 }};
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static const G4double cpositron[15][22] = {
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{2.589,2.044,1.658,1.446,1.347,1.217,1.144,1.110,
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1.097,1.083,1.080,1.086,1.092,1.108,1.123,1.131,
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1.131,1.126,1.117,1.108,1.103,1.100 },
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{3.904,2.794,2.079,1.710,1.543,1.325,1.202,1.145,
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1.122,1.096,1.089,1.092,1.098,1.114,1.130,1.137,
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1.138,1.132,1.122,1.113,1.108,1.102 },
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{7.970,6.080,4.442,3.398,2.872,2.127,1.672,1.451,
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1.357,1.246,1.194,1.179,1.178,1.188,1.201,1.205,
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1.203,1.190,1.173,1.159,1.151,1.145 },
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{9.714,7.607,5.747,4.493,3.815,2.777,2.079,1.715,
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1.553,1.353,1.253,1.219,1.211,1.214,1.225,1.228,
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1.225,1.210,1.191,1.175,1.166,1.174 },
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{17.97,12.95,8.628,6.065,4.849,3.222,2.275,1.820,
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1.624,1.382,1.259,1.214,1.202,1.202,1.214,1.219,
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1.217,1.203,1.184,1.169,1.160,1.151 },
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{24.83,17.06,10.84,7.355,5.767,3.707,2.546,1.996,
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1.759,1.465,1.311,1.252,1.234,1.228,1.238,1.241,
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1.237,1.222,1.201,1.184,1.174,1.159 },
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{23.26,17.15,11.52,8.049,6.375,4.114,2.792,2.155,
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1.880,1.535,1.353,1.281,1.258,1.247,1.254,1.256,
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1.252,1.234,1.212,1.194,1.183,1.170 },
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{22.33,18.01,12.86,9.212,7.336,4.702,3.117,2.348,
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2.015,1.602,1.385,1.297,1.268,1.251,1.256,1.258,
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1.254,1.237,1.214,1.195,1.185,1.179 },
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{33.91,24.13,15.71,10.80,8.507,5.467,3.692,2.808,
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2.407,1.873,1.564,1.425,1.374,1.330,1.324,1.320,
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1.312,1.288,1.258,1.235,1.221,1.205 },
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{32.14,24.11,16.30,11.40,9.015,5.782,3.868,2.917,
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2.490,1.925,1.596,1.447,1.391,1.342,1.332,1.327,
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1.320,1.294,1.264,1.240,1.226,1.214 },
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{29.51,24.07,17.19,12.28,9.766,6.238,4.112,3.066,
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2.602,1.995,1.641,1.477,1.414,1.356,1.342,1.336,
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1.328,1.302,1.270,1.245,1.231,1.233 },
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{38.19,30.85,21.76,15.35,12.07,7.521,4.812,3.498,
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2.926,2.188,1.763,1.563,1.484,1.405,1.382,1.371,
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1.361,1.330,1.294,1.267,1.251,1.239 },
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{49.71,39.80,27.96,19.63,15.36,9.407,5.863,4.155,
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3.417,2.478,1.944,1.692,1.589,1.480,1.441,1.423,
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1.409,1.372,1.330,1.298,1.280,1.258 },
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{59.25,45.08,30.36,20.83,16.15,9.834,6.166,4.407,
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3.641,2.648,2.064,1.779,1.661,1.531,1.482,1.459,
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1.442,1.400,1.354,1.319,1.299,1.272 },
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{56.38,44.29,30.50,21.18,16.51,10.11,6.354,4.542,
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3.752,2.724,2.116,1.817,1.692,1.554,1.499,1.474,
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1.456,1.412,1.364,1.328,1.307,1.282 }};
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//data/corrections for T > Tlim
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static const G4double hecorr[15] = {
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120.70, 117.50, 105.00, 92.92, 79.23, 74.510, 68.29,
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57.39, 41.97, 36.14, 24.53, 10.21, -7.855, -16.84,
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-22.30};
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G4double sigma;
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SetParticle(part);
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Z23 = G4Pow::GetInstance()->Z23(G4lrint(AtomicNumber));
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// correction if particle .ne. e-/e+
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// compute equivalent kinetic energy
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// lambda depends on p*beta ....
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G4double eKineticEnergy = KineticEnergy;
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if(mass > electron_mass_c2)
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{
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G4double TAU = KineticEnergy/mass ;
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G4double c = mass*TAU*(TAU+2.)/(electron_mass_c2*(TAU+1.)) ;
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G4double w = c-2. ;
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G4double tau = 0.5*(w+sqrt(w*w+4.*c)) ;
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eKineticEnergy = electron_mass_c2*tau ;
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}
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G4double eTotalEnergy = eKineticEnergy + electron_mass_c2 ;
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G4double beta2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2)
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/(eTotalEnergy*eTotalEnergy);
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G4double bg2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2)
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/(electron_mass_c2*electron_mass_c2);
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G4double eps = epsfactor*bg2/Z23;
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if (eps<epsmin) sigma = 2.*eps*eps;
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else if(eps<epsmax) sigma = G4Log(1.+2.*eps)-2.*eps/(1.+2.*eps);
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else sigma = G4Log(2.*eps)-1.+1./eps;
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sigma *= ChargeSquare*AtomicNumber*AtomicNumber/(beta2*bg2);
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// interpolate in AtomicNumber and beta2
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G4double c1,c2,cc1,cc2,corr;
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// get bin number in Z
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G4int iZ = 14;
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while ((iZ>=0)&&(Zdat[iZ]>=AtomicNumber)) iZ -= 1;
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if (iZ==14) iZ = 13;
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if (iZ==-1) iZ = 0 ;
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G4double ZZ1 = Zdat[iZ];
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G4double ZZ2 = Zdat[iZ+1];
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G4double ratZ = (AtomicNumber-ZZ1)*(AtomicNumber+ZZ1)/
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((ZZ2-ZZ1)*(ZZ2+ZZ1));
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if(eKineticEnergy <= Tlim)
|
|
{
|
|
// get bin number in T (beta2)
|
|
G4int iT = 21;
|
|
while ((iT>=0)&&(Tdat[iT]>=eKineticEnergy)) iT -= 1;
|
|
if(iT==21) iT = 20;
|
|
if(iT==-1) iT = 0 ;
|
|
|
|
// calculate betasquare values
|
|
G4double T = Tdat[iT], E = T + electron_mass_c2;
|
|
G4double b2small = T*(E+electron_mass_c2)/(E*E);
|
|
|
|
T = Tdat[iT+1]; E = T + electron_mass_c2;
|
|
G4double b2big = T*(E+electron_mass_c2)/(E*E);
|
|
G4double ratb2 = (beta2-b2small)/(b2big-b2small);
|
|
|
|
if (charge < 0.)
|
|
{
|
|
c1 = celectron[iZ][iT];
|
|
c2 = celectron[iZ+1][iT];
|
|
cc1 = c1+ratZ*(c2-c1);
|
|
|
|
c1 = celectron[iZ][iT+1];
|
|
c2 = celectron[iZ+1][iT+1];
|
|
cc2 = c1+ratZ*(c2-c1);
|
|
|
|
corr = cc1+ratb2*(cc2-cc1);
|
|
|
|
sigma *= sigmafactor/corr;
|
|
}
|
|
else
|
|
{
|
|
c1 = cpositron[iZ][iT];
|
|
c2 = cpositron[iZ+1][iT];
|
|
cc1 = c1+ratZ*(c2-c1);
|
|
|
|
c1 = cpositron[iZ][iT+1];
|
|
c2 = cpositron[iZ+1][iT+1];
|
|
cc2 = c1+ratZ*(c2-c1);
|
|
|
|
corr = cc1+ratb2*(cc2-cc1);
|
|
|
|
sigma *= sigmafactor/corr;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
c1 = bg2lim*sig0[iZ]*(1.+hecorr[iZ]*(beta2-beta2lim))/bg2;
|
|
c2 = bg2lim*sig0[iZ+1]*(1.+hecorr[iZ+1]*(beta2-beta2lim))/bg2;
|
|
if((AtomicNumber >= ZZ1) && (AtomicNumber <= ZZ2))
|
|
sigma = c1+ratZ*(c2-c1) ;
|
|
else if(AtomicNumber < ZZ1)
|
|
sigma = AtomicNumber*AtomicNumber*c1/(ZZ1*ZZ1);
|
|
else if(AtomicNumber > ZZ2)
|
|
sigma = AtomicNumber*AtomicNumber*c2/(ZZ2*ZZ2);
|
|
}
|
|
return sigma;
|
|
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
void G4UrbanMscModel::StartTracking(G4Track* track)
|
|
{
|
|
SetParticle(track->GetDynamicParticle()->GetDefinition());
|
|
firstStep = true;
|
|
inside = false;
|
|
insideskin = false;
|
|
tlimit = geombig;
|
|
stepmin = tlimitminfix ;
|
|
tlimitmin = 10.*stepmin ;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::ComputeTruePathLengthLimit(
|
|
const G4Track& track,
|
|
G4double& currentMinimalStep)
|
|
{
|
|
tPathLength = currentMinimalStep;
|
|
const G4DynamicParticle* dp = track.GetDynamicParticle();
|
|
|
|
G4StepPoint* sp = track.GetStep()->GetPreStepPoint();
|
|
G4StepStatus stepStatus = sp->GetStepStatus();
|
|
couple = track.GetMaterialCutsCouple();
|
|
SetCurrentCouple(couple);
|
|
currentMaterialIndex = couple->GetIndex();
|
|
currentKinEnergy = dp->GetKineticEnergy();
|
|
currentRange = GetRange(particle,currentKinEnergy,couple);
|
|
lambda0 = GetTransportMeanFreePath(particle,currentKinEnergy);
|
|
if(tPathLength > currentRange) { tPathLength = currentRange; }
|
|
|
|
// stop here if small range particle
|
|
if(inside || tPathLength < tlimitminfix) {
|
|
return ConvertTrueToGeom(tPathLength, currentMinimalStep);
|
|
}
|
|
|
|
presafety = sp->GetSafety();
|
|
/*
|
|
G4cout << "G4Urban96::StepLimit tPathLength= "
|
|
<<tPathLength<<" safety= " << presafety
|
|
<< " range= " <<currentRange<< " lambda= "<<lambda0
|
|
<< " Alg: " << steppingAlgorithm <<G4endl;
|
|
*/
|
|
// far from geometry boundary
|
|
if(currentRange < presafety)
|
|
{
|
|
inside = true;
|
|
return ConvertTrueToGeom(tPathLength, currentMinimalStep);
|
|
}
|
|
|
|
// standard version
|
|
//
|
|
if (steppingAlgorithm == fUseDistanceToBoundary)
|
|
{
|
|
//compute geomlimit and presafety
|
|
geomlimit = ComputeGeomLimit(track, presafety, currentRange);
|
|
|
|
// is it far from boundary ?
|
|
if(currentRange < presafety)
|
|
{
|
|
inside = true;
|
|
return ConvertTrueToGeom(tPathLength, currentMinimalStep);
|
|
}
|
|
|
|
smallstep += 1.;
|
|
insideskin = false;
|
|
|
|
if(firstStep || (stepStatus == fGeomBoundary))
|
|
{
|
|
rangeinit = currentRange;
|
|
if(firstStep) smallstep = 1.e10;
|
|
else smallstep = 1.;
|
|
|
|
//define stepmin here (it depends on lambda!)
|
|
//rough estimation of lambda_elastic/lambda_transport
|
|
G4double rat = currentKinEnergy/MeV ;
|
|
rat = 1.e-3/(rat*(10.+rat)) ;
|
|
//stepmin ~ lambda_elastic
|
|
stepmin = rat*lambda0;
|
|
skindepth = skin*stepmin;
|
|
//define tlimitmin
|
|
tlimitmin = 10.*stepmin;
|
|
if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix;
|
|
//G4cout << "rangeinit= " << rangeinit << " stepmin= " << stepmin
|
|
// << " tlimitmin= " << tlimitmin << " geomlimit= " << geomlimit <<G4endl;
|
|
// constraint from the geometry
|
|
if((geomlimit < geombig) && (geomlimit > geommin))
|
|
{
|
|
// geomlimit is a geometrical step length
|
|
// transform it to true path length (estimation)
|
|
if((1.-geomlimit/lambda0) > 0.)
|
|
geomlimit = -lambda0*G4Log(1.-geomlimit/lambda0)+tlimitmin ;
|
|
|
|
if(stepStatus == fGeomBoundary)
|
|
tgeom = geomlimit/facgeom;
|
|
else
|
|
tgeom = 2.*geomlimit/facgeom;
|
|
}
|
|
else
|
|
tgeom = geombig;
|
|
}
|
|
|
|
|
|
//step limit
|
|
tlimit = facrange*rangeinit;
|
|
|
|
//lower limit for tlimit
|
|
if(tlimit < tlimitmin) tlimit = tlimitmin;
|
|
|
|
if(tlimit > tgeom) tlimit = tgeom;
|
|
|
|
//G4cout << "tgeom= " << tgeom << " geomlimit= " << geomlimit
|
|
// << " tlimit= " << tlimit << " presafety= " << presafety << G4endl;
|
|
|
|
// shortcut
|
|
if((tPathLength < tlimit) && (tPathLength < presafety) &&
|
|
(smallstep > skin) && (tPathLength < geomlimit-0.999*skindepth))
|
|
return ConvertTrueToGeom(tPathLength, currentMinimalStep);
|
|
|
|
// step reduction near to boundary
|
|
if(smallstep <= skin)
|
|
{
|
|
tlimit = stepmin;
|
|
insideskin = true;
|
|
}
|
|
else if(geomlimit < geombig)
|
|
{
|
|
if(geomlimit > skindepth)
|
|
{
|
|
if(tlimit > geomlimit-0.999*skindepth)
|
|
tlimit = geomlimit-0.999*skindepth;
|
|
}
|
|
else
|
|
{
|
|
insideskin = true;
|
|
if(tlimit > stepmin) tlimit = stepmin;
|
|
}
|
|
}
|
|
|
|
if(tlimit < stepmin) tlimit = stepmin;
|
|
|
|
// randomize 1st step or 1st 'normal' step in volume
|
|
if(firstStep || ((smallstep == skin) && !insideskin))
|
|
{
|
|
G4double temptlimit = tlimit;
|
|
if(temptlimit > tlimitmin)
|
|
{
|
|
do {
|
|
temptlimit = G4RandGauss::shoot(tlimit,0.3*tlimit);
|
|
} while ((temptlimit < tlimitmin) ||
|
|
(temptlimit > 2.*tlimit-tlimitmin));
|
|
}
|
|
else
|
|
temptlimit = tlimitmin;
|
|
if(tPathLength > temptlimit) tPathLength = temptlimit;
|
|
}
|
|
else
|
|
{
|
|
if(tPathLength > tlimit) tPathLength = tlimit ;
|
|
}
|
|
|
|
}
|
|
// for 'normal' simulation with or without magnetic field
|
|
// there no small step/single scattering at boundaries
|
|
else if(steppingAlgorithm == fUseSafety)
|
|
{
|
|
// compute presafety again if presafety <= 0 and no boundary
|
|
// i.e. when it is needed for optimization purposes
|
|
if((stepStatus != fGeomBoundary) && (presafety < tlimitminfix))
|
|
presafety = ComputeSafety(sp->GetPosition(),tPathLength);
|
|
/*
|
|
G4cout << "presafety= " << presafety
|
|
<< " firstStep= " << firstStep
|
|
<< " stepStatus= " << stepStatus
|
|
<< G4endl;
|
|
*/
|
|
// is far from boundary
|
|
if(currentRange < presafety)
|
|
{
|
|
inside = true;
|
|
return ConvertTrueToGeom(tPathLength, currentMinimalStep);
|
|
}
|
|
|
|
if(firstStep || stepStatus == fGeomBoundary)
|
|
{
|
|
rangeinit = currentRange;
|
|
fr = facrange;
|
|
// 9.1 like stepping for e+/e- only (not for muons,hadrons)
|
|
if(mass < masslimite)
|
|
{
|
|
if(lambda0 > currentRange)
|
|
rangeinit = lambda0;
|
|
if(lambda0 > lambdalimit)
|
|
fr *= 0.75+0.25*lambda0/lambdalimit;
|
|
}
|
|
|
|
//lower limit for tlimit
|
|
G4double rat = currentKinEnergy/MeV ;
|
|
rat = 1.e-3/(rat*(10.+rat)) ;
|
|
stepmin = lambda0*rat;
|
|
tlimitmin = 10.*stepmin;
|
|
if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix;
|
|
}
|
|
//step limit
|
|
tlimit = fr*rangeinit;
|
|
|
|
if(tlimit < facsafety*presafety)
|
|
tlimit = facsafety*presafety;
|
|
|
|
//lower limit for tlimit
|
|
if(tlimit < tlimitmin) tlimit = tlimitmin;
|
|
|
|
if(firstStep || stepStatus == fGeomBoundary)
|
|
{
|
|
G4double temptlimit = tlimit;
|
|
if(temptlimit > tlimitmin)
|
|
{
|
|
do {
|
|
temptlimit = G4RandGauss::shoot(tlimit,0.3*tlimit);
|
|
} while ((temptlimit < tlimitmin) ||
|
|
(temptlimit > 2.*tlimit-tlimitmin));
|
|
}
|
|
else
|
|
temptlimit = tlimitmin;
|
|
|
|
if(tPathLength > temptlimit) tPathLength = temptlimit;
|
|
}
|
|
else
|
|
if(tPathLength > tlimit) tPathLength = tlimit;
|
|
|
|
}
|
|
|
|
// version similar to 7.1 (needed for some experiments)
|
|
else
|
|
{
|
|
if (stepStatus == fGeomBoundary)
|
|
{
|
|
if (currentRange > lambda0) tlimit = facrange*currentRange;
|
|
else tlimit = facrange*lambda0;
|
|
|
|
if(tlimit < tlimitmin) tlimit = tlimitmin;
|
|
}
|
|
|
|
if(firstStep || stepStatus == fGeomBoundary)
|
|
{
|
|
G4double temptlimit = tlimit;
|
|
if(temptlimit > tlimitmin)
|
|
{
|
|
do {
|
|
temptlimit = G4RandGauss::shoot(tlimit,0.3*tlimit);
|
|
} while ((temptlimit < tlimitmin) ||
|
|
(temptlimit > 2.*tlimit-tlimitmin));
|
|
}
|
|
else
|
|
temptlimit = tlimitmin;
|
|
|
|
if(tPathLength > temptlimit) tPathLength = temptlimit;
|
|
}
|
|
else
|
|
if(tPathLength > tlimit) tPathLength = tlimit;
|
|
}
|
|
//G4cout << "tPathLength= " << tPathLength
|
|
// << " currentMinimalStep= " << currentMinimalStep << G4endl;
|
|
return ConvertTrueToGeom(tPathLength, currentMinimalStep);
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::ComputeGeomPathLength(G4double)
|
|
{
|
|
firstStep = false;
|
|
lambdaeff = lambda0;
|
|
par1 = -1. ;
|
|
par2 = par3 = 0. ;
|
|
|
|
// do the true -> geom transformation
|
|
zPathLength = tPathLength;
|
|
|
|
// z = t for very small tPathLength
|
|
if(tPathLength < tlimitminfix2) return zPathLength;
|
|
|
|
// this correction needed to run MSC with eIoni and eBrem inactivated
|
|
// and makes no harm for a normal run
|
|
// It is already checked
|
|
// if(tPathLength > currentRange)
|
|
// tPathLength = currentRange ;
|
|
|
|
G4double tau = tPathLength/lambda0 ;
|
|
|
|
if ((tau <= tausmall) || insideskin) {
|
|
zPathLength = tPathLength;
|
|
if(zPathLength > lambda0) zPathLength = lambda0;
|
|
return zPathLength;
|
|
}
|
|
|
|
G4double zmean = tPathLength;
|
|
if (tPathLength < currentRange*dtrl) {
|
|
if(tau < taulim) zmean = tPathLength*(1.-0.5*tau) ;
|
|
else zmean = lambda0*(1.-G4Exp(-tau));
|
|
zPathLength = zmean ;
|
|
return zPathLength;
|
|
|
|
} else if(currentKinEnergy < mass || tPathLength == currentRange) {
|
|
par1 = 1./currentRange ;
|
|
par2 = 1./(par1*lambda0) ;
|
|
par3 = 1.+par2 ;
|
|
if(tPathLength < currentRange)
|
|
zmean = (1.-G4Exp(par3*G4Log(1.-tPathLength/currentRange)))/(par1*par3) ;
|
|
else {
|
|
zmean = 1./(par1*par3) ;
|
|
}
|
|
zPathLength = zmean ;
|
|
return zPathLength;
|
|
|
|
} else {
|
|
G4double T1 = GetEnergy(particle,currentRange-tPathLength,couple);
|
|
G4double lambda1 = GetTransportMeanFreePath(particle,T1);
|
|
|
|
par1 = (lambda0-lambda1)/(lambda0*tPathLength);
|
|
par2 = 1./(par1*lambda0);
|
|
par3 = 1.+par2 ;
|
|
zmean = (1.-G4Exp(par3*G4Log(lambda1/lambda0)))/(par1*par3);
|
|
}
|
|
|
|
zPathLength = zmean;
|
|
|
|
if(zPathLength > lambda0) { zPathLength = lambda0; }
|
|
//G4cout<< "zPathLength= "<< zPathLength<< " lambda1= " << lambda0 << G4endl;
|
|
return zPathLength;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::ComputeTrueStepLength(G4double geomStepLength)
|
|
{
|
|
// step defined other than transportation
|
|
if(geomStepLength == zPathLength)
|
|
{ return tPathLength; }
|
|
|
|
zPathLength = geomStepLength;
|
|
|
|
// t = z for very small step
|
|
if(geomStepLength < tlimitminfix2) {
|
|
tPathLength = geomStepLength;
|
|
|
|
// recalculation
|
|
} else {
|
|
|
|
G4double tlength = geomStepLength;
|
|
if((geomStepLength > lambda0*tausmall) && !insideskin) {
|
|
|
|
if(par1 < 0.) {
|
|
tlength = -lambda0*G4Log(1.-geomStepLength/lambda0) ;
|
|
} else {
|
|
if(par1*par3*geomStepLength < 1.) {
|
|
tlength = (1.-G4Exp(G4Log(1.-par1*par3*geomStepLength)/par3))/par1 ;
|
|
} else {
|
|
tlength = currentRange;
|
|
}
|
|
}
|
|
if(tlength < geomStepLength) { tlength = geomStepLength; }
|
|
else if(tlength > tPathLength) { tlength = tPathLength; }
|
|
}
|
|
tPathLength = tlength;
|
|
}
|
|
//G4cout << "Urban96::ComputeTrueLength: tPathLength= " << tPathLength
|
|
// << " step= " << geomStepLength << G4endl;
|
|
|
|
return tPathLength;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::ComputeTheta0(G4double trueStepLength,
|
|
G4double KineticEnergy)
|
|
{
|
|
// for all particles take the width of the central part
|
|
// from a parametrization similar to the Highland formula
|
|
// ( Highland formula: Particle Physics Booklet, July 2002, eq. 26.10)
|
|
G4double betacp = sqrt(currentKinEnergy*(currentKinEnergy+2.*mass)*
|
|
KineticEnergy*(KineticEnergy+2.*mass)/
|
|
((currentKinEnergy+mass)*(KineticEnergy+mass)));
|
|
y = trueStepLength/currentRadLength;
|
|
G4double theta0 = c_highland*std::abs(charge)*sqrt(y)/betacp;
|
|
y = G4Log(y);
|
|
// correction factor from e- scattering data
|
|
G4double corr = coeffth1+coeffth2*y;
|
|
|
|
theta0 *= corr ;
|
|
|
|
return theta0;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4ThreeVector&
|
|
G4UrbanMscModel::SampleScattering(const G4ThreeVector& oldDirection,
|
|
G4double safety)
|
|
{
|
|
fDisplacement.set(0.0,0.0,0.0);
|
|
G4double kineticEnergy = currentKinEnergy;
|
|
if (tPathLength > currentRange*dtrl) {
|
|
kineticEnergy = GetEnergy(particle,currentRange-tPathLength,couple);
|
|
} else {
|
|
kineticEnergy -= tPathLength*GetDEDX(particle,currentKinEnergy,couple);
|
|
}
|
|
|
|
if((kineticEnergy <= eV) || (tPathLength <= tlimitminfix) ||
|
|
(tPathLength/tausmall < lambda0)) { return fDisplacement; }
|
|
|
|
G4double cth = SampleCosineTheta(tPathLength,kineticEnergy);
|
|
|
|
// protection against 'bad' cth values
|
|
if(std::fabs(cth) > 1.) { return fDisplacement; }
|
|
|
|
// extra protection agaist high energy particles backscattered
|
|
//G4cout << "Warning: large scattering E(MeV)= " << kineticEnergy
|
|
// << " s(mm)= " << tPathLength/mm
|
|
// << " 1-cosTheta= " << 1.0 - cth << G4endl;
|
|
// do Gaussian central scattering
|
|
// if(kineticEnergy > 5*GeV && cth < 0.9) {
|
|
/*
|
|
if(cth < 1.0 - 1000*tPathLength/lambda0 && cth < 0.5 &&
|
|
kineticEnergy > 20*MeV) {
|
|
G4cout << "### G4UrbanMscModel::SampleScattering for "
|
|
<< particle->GetParticleName()
|
|
<< " E(MeV)= " << kineticEnergy/MeV
|
|
<< " Step(mm)= " << tPathLength/mm
|
|
<< " in " << CurrentCouple()->GetMaterial()->GetName()
|
|
<< " CosTheta= " << cth << G4endl;
|
|
}
|
|
*/
|
|
G4double sth = sqrt((1.0 - cth)*(1.0 + cth));
|
|
G4double phi = twopi*G4UniformRand();
|
|
G4double dirx = sth*cos(phi);
|
|
G4double diry = sth*sin(phi);
|
|
|
|
G4ThreeVector newDirection(dirx,diry,cth);
|
|
newDirection.rotateUz(oldDirection);
|
|
fParticleChange->ProposeMomentumDirection(newDirection);
|
|
/*
|
|
G4cout << "G4UrbanMscModel::SampleSecondaries: e(MeV)= " << kineticEnergy
|
|
<< " sinTheta= " << sth << " safety(mm)= " << safety
|
|
<< " trueStep(mm)= " << tPathLength
|
|
<< " geomStep(mm)= " << zPathLength
|
|
<< G4endl;
|
|
*/
|
|
if (latDisplasment && safety > tlimitminfix2) {
|
|
|
|
G4double r = SampleDisplacement();
|
|
/*
|
|
G4cout << "G4UrbanMscModel::SampleSecondaries: e(MeV)= " << kineticEnergy
|
|
<< " sinTheta= " << sth << " r(mm)= " << r
|
|
<< " trueStep(mm)= " << tPathLength
|
|
<< " geomStep(mm)= " << zPathLength
|
|
<< G4endl;
|
|
*/
|
|
if(r > 0.)
|
|
{
|
|
G4double latcorr = LatCorrelation();
|
|
if(latcorr > r) latcorr = r;
|
|
|
|
// sample direction of lateral displacement
|
|
// compute it from the lateral correlation
|
|
G4double Phi = 0.;
|
|
if(std::abs(r*sth) < latcorr)
|
|
Phi = twopi*G4UniformRand();
|
|
else
|
|
{
|
|
G4double psi = std::acos(latcorr/(r*sth));
|
|
if(G4UniformRand() < 0.5)
|
|
Phi = phi+psi;
|
|
else
|
|
Phi = phi-psi;
|
|
}
|
|
|
|
dirx = std::cos(Phi);
|
|
diry = std::sin(Phi);
|
|
|
|
fDisplacement.set(r*dirx,r*diry,0.0);
|
|
fDisplacement.rotateUz(oldDirection);
|
|
}
|
|
}
|
|
return fDisplacement;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::SampleCosineTheta(G4double trueStepLength,
|
|
G4double KineticEnergy)
|
|
{
|
|
G4double cth = 1. ;
|
|
G4double tau = trueStepLength/lambda0;
|
|
currentTau = tau;
|
|
lambdaeff = lambda0;
|
|
|
|
Zeff = couple->GetMaterial()->GetTotNbOfElectPerVolume()/
|
|
couple->GetMaterial()->GetTotNbOfAtomsPerVolume() ;
|
|
|
|
if(Zold != Zeff)
|
|
UpdateCache();
|
|
|
|
G4double lambda1 = GetTransportMeanFreePath(particle,KineticEnergy);
|
|
if(std::fabs(lambda1/lambda0 - 1) > 0.01 && lambda1 > 0.)
|
|
{
|
|
// mean tau value
|
|
tau = trueStepLength*G4Log(lambda0/lambda1)/(lambda0-lambda1);
|
|
}
|
|
|
|
currentTau = tau ;
|
|
lambdaeff = trueStepLength/currentTau;
|
|
currentRadLength = couple->GetMaterial()->GetRadlen();
|
|
|
|
if (tau >= taubig) { cth = -1.+2.*G4UniformRand(); }
|
|
else if (tau >= tausmall) {
|
|
static const G4double numlim = 0.01;
|
|
G4double xmeanth, x2meanth;
|
|
if(tau < numlim) {
|
|
xmeanth = 1.0 - tau*(1.0 - 0.5*tau);
|
|
x2meanth= 1.0 - tau*(5.0 - 6.25*tau)/3.;
|
|
} else {
|
|
xmeanth = G4Exp(-tau);
|
|
x2meanth = (1.+2.*G4Exp(-2.5*tau))/3.;
|
|
}
|
|
G4double relloss = 1.-KineticEnergy/currentKinEnergy;
|
|
|
|
if(relloss > rellossmax)
|
|
return SimpleScattering(xmeanth,x2meanth);
|
|
|
|
// is step extreme small ?
|
|
G4bool extremesmallstep = false ;
|
|
G4double tsmall = tlimitmin;
|
|
G4double theta0 = 0.;
|
|
if(trueStepLength > tsmall) {
|
|
theta0 = ComputeTheta0(trueStepLength,KineticEnergy);
|
|
} else {
|
|
G4double rate = trueStepLength/tsmall ;
|
|
if(G4UniformRand() < rate) {
|
|
theta0 = ComputeTheta0(tsmall,KineticEnergy);
|
|
extremesmallstep = true ;
|
|
}
|
|
}
|
|
//G4cout << "Theta0= " << theta0 << " theta0max= " << theta0max
|
|
// << " sqrt(tausmall)= " << sqrt(tausmall) << G4endl;
|
|
|
|
// protection for very small angles
|
|
G4double theta2 = theta0*theta0;
|
|
|
|
if(theta2 < tausmall) { return cth; }
|
|
|
|
if(theta0 > theta0max) {
|
|
return SimpleScattering(xmeanth,x2meanth);
|
|
}
|
|
|
|
G4double x = theta2*(1.0 - theta2/12.);
|
|
if(theta2 > numlim) {
|
|
G4double sth = 2*sin(0.5*theta0);
|
|
x = sth*sth;
|
|
}
|
|
|
|
// parameter for tail
|
|
G4double ltau= G4Log(tau);
|
|
G4double u = G4Exp(ltau/6.);
|
|
if(extremesmallstep) u = G4Exp(G4Log(tsmall/lambda0)/6.);
|
|
G4double xx = G4Log(lambdaeff/currentRadLength);
|
|
G4double xsi = coeffc1+u*(coeffc2+coeffc3*u)+coeffc4*xx;
|
|
|
|
// tail should not be too big
|
|
if(xsi < 1.9) {
|
|
/*
|
|
if(KineticEnergy > 20*MeV && xsi < 1.6) {
|
|
G4cout << "G4UrbanMscModel::SampleCosineTheta: E(GeV)= "
|
|
<< KineticEnergy/GeV
|
|
<< " !!** c= " << xsi
|
|
<< " **!! length(mm)= " << trueStepLength << " Zeff= " << Zeff
|
|
<< " " << couple->GetMaterial()->GetName()
|
|
<< " tau= " << tau << G4endl;
|
|
}
|
|
*/
|
|
xsi = 1.9;
|
|
}
|
|
|
|
G4double c = xsi;
|
|
|
|
if(fabs(c-3.) < 0.001) { c = 3.001; }
|
|
else if(fabs(c-2.) < 0.001) { c = 2.001; }
|
|
|
|
G4double c1 = c-1.;
|
|
|
|
G4double ea = G4Exp(-xsi);
|
|
G4double eaa = 1.-ea ;
|
|
G4double xmean1 = 1.-(1.-(1.+xsi)*ea)*x/eaa;
|
|
G4double x0 = 1. - xsi*x;
|
|
|
|
// G4cout << " xmean1= " << xmean1 << " xmeanth= " << xmeanth << G4endl;
|
|
|
|
if(xmean1 <= 0.999*xmeanth) {
|
|
return SimpleScattering(xmeanth,x2meanth);
|
|
}
|
|
//from continuity of derivatives
|
|
G4double b = 1.+(c-xsi)*x;
|
|
|
|
G4double b1 = b+1.;
|
|
G4double bx = c*x;
|
|
|
|
G4double eb1 = G4Exp(G4Log(b1)*c1);
|
|
G4double ebx = G4Exp(G4Log(bx)*c1);
|
|
G4double d = ebx/eb1;
|
|
|
|
G4double xmean2 = (x0 + d - (bx - b1*d)/(c-2.))/(1. - d);
|
|
|
|
G4double f1x0 = ea/eaa;
|
|
G4double f2x0 = c1/(c*(1. - d));
|
|
G4double prob = f2x0/(f1x0+f2x0);
|
|
|
|
G4double qprob = xmeanth/(prob*xmean1+(1.-prob)*xmean2);
|
|
|
|
// sampling of costheta
|
|
//G4cout << "c= " << c << " qprob= " << qprob << " eb1= " << eb1
|
|
// << " c1= " << c1 << " b1= " << b1 << " bx= " << bx << " eb1= " << eb1
|
|
// << G4endl;
|
|
if(G4UniformRand() < qprob)
|
|
{
|
|
G4double var = 0;
|
|
if(G4UniformRand() < prob) {
|
|
cth = 1.+G4Log(ea+G4UniformRand()*eaa)*x;
|
|
} else {
|
|
var = (1.0 - d)*G4UniformRand();
|
|
if(var < numlim*d) {
|
|
var /= (d*c1);
|
|
cth = -1.0 + var*(1.0 - 0.5*var*c)*(2. + (c - xsi)*x);
|
|
} else {
|
|
cth = 1. + x*(c - xsi - c*G4Exp(-G4Log(var + d)/c1));
|
|
//b-b1*bx/G4Exp(G4Log(ebx+(eb1-ebx)*G4UniformRand())/c1) ;
|
|
}
|
|
}
|
|
if(KineticEnergy > 5*GeV && cth < 0.9) {
|
|
G4cout << "G4UrbanMscModel::SampleCosineTheta: E(GeV)= "
|
|
<< KineticEnergy/GeV
|
|
<< " 1-cosT= " << 1 - cth
|
|
<< " length(mm)= " << trueStepLength << " Zeff= " << Zeff
|
|
<< " tau= " << tau
|
|
<< " prob= " << prob << " var= " << var << G4endl;
|
|
G4cout << " c= " << c << " qprob= " << qprob << " eb1= " << eb1
|
|
<< " ebx= " << ebx
|
|
<< " c1= " << c1 << " b= " << b << " b1= " << b1
|
|
<< " bx= " << bx << " d= " << d
|
|
<< " ea= " << ea << " eaa= " << eaa << G4endl;
|
|
}
|
|
}
|
|
else {
|
|
cth = -1.+2.*G4UniformRand();
|
|
if(KineticEnergy > 5*GeV) {
|
|
G4cout << "G4UrbanMscModel::SampleCosineTheta: E(GeV)= "
|
|
<< KineticEnergy/GeV
|
|
<< " length(mm)= " << trueStepLength << " Zeff= " << Zeff
|
|
<< " qprob= " << qprob << G4endl;
|
|
}
|
|
}
|
|
}
|
|
return cth ;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::SimpleScattering(G4double xmeanth,G4double x2meanth)
|
|
{
|
|
// 'large angle scattering'
|
|
// 2 model functions with correct xmean and x2mean
|
|
G4double a = (2.*xmeanth+9.*x2meanth-3.)/(2.*xmeanth-3.*x2meanth+1.);
|
|
G4double prob = (a+2.)*xmeanth/a;
|
|
|
|
// sampling
|
|
G4double cth = 1.;
|
|
if(G4UniformRand() < prob)
|
|
cth = -1.+2.*G4Exp(G4Log(G4UniformRand())/(a+1.));
|
|
else
|
|
cth = -1.+2.*G4UniformRand();
|
|
return cth;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::SampleDisplacement()
|
|
{
|
|
G4double r = 0.0;
|
|
if ((currentTau >= tausmall) && !insideskin) {
|
|
G4double rmax = sqrt((tPathLength-zPathLength)*(tPathLength+zPathLength));
|
|
r = rmax*G4Exp(G4Log(G4UniformRand())/3.);
|
|
}
|
|
return r;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::LatCorrelation()
|
|
{
|
|
static const G4double kappa = 2.5;
|
|
static const G4double kappami1 = kappa-1.;
|
|
|
|
G4double latcorr = 0.;
|
|
if((currentTau >= tausmall) && !insideskin)
|
|
{
|
|
if(currentTau < taulim)
|
|
latcorr = lambdaeff*kappa*currentTau*currentTau*
|
|
(1.-(kappa+1.)*currentTau/3.)/3.;
|
|
else
|
|
{
|
|
G4double etau = 0.;
|
|
if(currentTau < taubig) etau = G4Exp(-currentTau);
|
|
latcorr = -kappa*currentTau;
|
|
latcorr = G4Exp(latcorr)/kappami1;
|
|
latcorr += 1.-kappa*etau/kappami1 ;
|
|
latcorr *= 2.*lambdaeff/3. ;
|
|
}
|
|
}
|
|
|
|
return latcorr;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|