[1337] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // $Id: G4GoudsmitSaundersonMscModel.cc,v 1.25 2010/06/25 09:41:40 gunter Exp $ |
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| 27 | // GEANT4 tag $Name: geant4-09-04-beta-01 $ |
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| 28 | // |
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| 29 | // ------------------------------------------------------------------- |
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| 30 | // |
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| 31 | // GEANT4 Class file |
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| 32 | // |
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| 33 | // File name: G4GoudsmitSaundersonMscModel |
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| 34 | // |
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| 35 | // Author: Omrane Kadri |
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| 36 | // |
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| 37 | // Creation date: 20.02.2009 |
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| 38 | // |
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| 39 | // Modifications: |
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| 40 | // 04.03.2009 V.Ivanchenko cleanup and format according to Geant4 EM style |
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| 41 | // |
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| 42 | // 15.04.2009 O.Kadri: cleanup: discard no scattering and single scattering theta |
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| 43 | // sampling from SampleCosineTheta() which means the splitting |
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| 44 | // step into two sub-steps occur only for msc regime |
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| 45 | // |
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| 46 | // 12.06.2009 O.Kadri: linear log-log extrapolation of lambda0 & lambda1 between 1 GeV - 100 TeV |
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| 47 | // adding a theta min limit due to screening effect of the atomic nucleus |
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| 48 | // 26.08.2009 O.Kadri: Cubic Spline interpolation was replaced with polynomial method |
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| 49 | // within CalculateIntegrals method |
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| 50 | // 05.10.2009 O.Kadri: tuning small angle theta distributions |
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| 51 | // assuming the case of lambdan<1 as single scattering regime |
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| 52 | // tuning theta sampling for theta below the screening angle |
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| 53 | // 08.02.2010 O.Kadri: bugfix in compound xsection calculation and small angle computation |
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| 54 | // adding a rejection condition to hard collision angular sampling |
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| 55 | // ComputeTruePathLengthLimit was taken from G4WentzelVIModel |
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| 56 | // 26.03.2010 O.Kadri: direct xsection calculation not inverse of the inverse |
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| 57 | // angular sampling without large angle rejection method |
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| 58 | // longitudinal displacement is computed exactly from <z> |
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| 59 | // 12.05.2010 O.Kadri: exchange between target and projectile has as a condition the particle type (e-/e-) |
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| 60 | // some cleanup to minimize time consuming (adding lamdan12 & Qn12, changing the error to 1.0e-12 for scrA) |
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| 61 | // |
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| 62 | // |
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| 63 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 64 | //REFERENCES: |
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| 65 | //Ref.1:E. Benedito et al.,"Mixed simulation ... cross-sections", NIMB 174 (2001) pp 91-110; |
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| 66 | //Ref.2:I. Kawrakow et al.,"On the condensed ... transport",NIMB 142 (1998) pp 253-280; |
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| 67 | //Ref.3:I. Kawrakow et al.,"On the representation ... calculations",NIMB 134 (1998) pp 325-336; |
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| 68 | //Ref.4:Bielajew et al.,".....", NIMB 173 (2001) 332-343; |
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| 69 | //Ref.5:F. Salvat et al.,"ELSEPA--Dirac partial ...molecules", Comp.Phys.Comm.165 (2005) pp 157-190; |
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| 70 | //Ref.6:G4UrbanMscModel G4 9.2; |
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| 71 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 72 | #include "G4GoudsmitSaundersonMscModel.hh" |
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| 73 | #include "G4GoudsmitSaundersonTable.hh" |
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| 74 | |
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| 75 | #include "G4ParticleChangeForMSC.hh" |
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| 76 | #include "G4MaterialCutsCouple.hh" |
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| 77 | #include "G4DynamicParticle.hh" |
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| 78 | #include "G4Electron.hh" |
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| 79 | #include "G4Positron.hh" |
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| 80 | |
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| 81 | #include "G4LossTableManager.hh" |
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| 82 | #include "G4Track.hh" |
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| 83 | #include "G4PhysicsTable.hh" |
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| 84 | #include "Randomize.hh" |
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| 85 | |
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| 86 | using namespace std; |
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| 87 | |
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| 88 | G4double G4GoudsmitSaundersonMscModel::ener[] = {-1.}; |
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| 89 | G4double G4GoudsmitSaundersonMscModel::TCSE[103][106] ; |
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| 90 | G4double G4GoudsmitSaundersonMscModel::FTCSE[103][106] ; |
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| 91 | G4double G4GoudsmitSaundersonMscModel::TCSP[103][106] ; |
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| 92 | G4double G4GoudsmitSaundersonMscModel::FTCSP[103][106] ; |
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| 93 | |
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| 94 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 95 | G4GoudsmitSaundersonMscModel::G4GoudsmitSaundersonMscModel(const G4String& nam) |
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| 96 | : G4VMscModel(nam),lowKEnergy(0.1*keV),highKEnergy(100.*TeV),isInitialized(false) |
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| 97 | { |
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| 98 | fr=0.02,rangeinit=0.,masslimite=0.6*MeV, |
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| 99 | particle=0;tausmall=1.e-16;taulim=1.e-6;tlimit=1.e10*mm; |
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| 100 | tlimitmin=10.e-6*mm;geombig=1.e50*mm;geommin=1.e-3*mm,tgeom=geombig; |
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| 101 | tlimitminfix=1.e-6*mm;stepmin=tlimitminfix;lambdalimit=1.*mm;smallstep=1.e10; |
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| 102 | theManager=G4LossTableManager::Instance(); |
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| 103 | inside=false;insideskin=false; |
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| 104 | samplez=false; |
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| 105 | |
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| 106 | GSTable = new G4GoudsmitSaundersonTable(); |
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| 107 | |
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| 108 | if(ener[0] < 0.0){ |
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| 109 | G4cout << "### G4GoudsmitSaundersonMscModel loading ELSEPA data" << G4endl; |
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| 110 | LoadELSEPAXSections(); |
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| 111 | } |
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| 112 | } |
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| 113 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 114 | G4GoudsmitSaundersonMscModel::~G4GoudsmitSaundersonMscModel() |
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| 115 | { |
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| 116 | delete GSTable; |
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| 117 | } |
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| 118 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 119 | void G4GoudsmitSaundersonMscModel::Initialise(const G4ParticleDefinition* p, |
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| 120 | const G4DataVector&) |
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| 121 | { |
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| 122 | skindepth=skin*stepmin; |
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| 123 | SetParticle(p); |
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| 124 | if(isInitialized) return; |
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| 125 | fParticleChange = GetParticleChangeForMSC(); |
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| 126 | InitialiseSafetyHelper(); |
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| 127 | isInitialized=true; |
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| 128 | } |
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| 129 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 130 | |
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| 131 | G4double |
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| 132 | G4GoudsmitSaundersonMscModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition* p, |
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| 133 | G4double kineticEnergy,G4double Z, G4double, G4double, G4double) |
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| 134 | { |
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| 135 | G4double cs=0.0; |
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| 136 | G4double kinEnergy = kineticEnergy; |
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| 137 | if(kinEnergy<lowKEnergy) kinEnergy=lowKEnergy; |
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| 138 | if(kinEnergy>highKEnergy)kinEnergy=highKEnergy; |
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| 139 | |
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| 140 | G4double cs0; |
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| 141 | CalculateIntegrals(p,Z,kinEnergy,cs0,cs); |
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| 142 | |
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| 143 | return cs; |
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| 144 | } |
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| 145 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 146 | |
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| 147 | void |
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| 148 | G4GoudsmitSaundersonMscModel::SampleScattering(const G4DynamicParticle* dynParticle, |
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| 149 | G4double safety) |
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| 150 | { |
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| 151 | G4double kineticEnergy = dynParticle->GetKineticEnergy(); |
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| 152 | if((kineticEnergy <= 0.0) || (tPathLength <= tlimitminfix)|| |
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| 153 | (tPathLength/tausmall < lambda1)) return ; |
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| 154 | |
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| 155 | /////////////////////////////////////////// |
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| 156 | // Effective energy |
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| 157 | G4double eloss = theManager->GetEnergy(particle,tPathLength,currentCouple); |
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| 158 | if(eloss>0.5*kineticEnergy) |
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| 159 | {if((dynParticle->GetCharge())==-eplus)eloss=kineticEnergy-eloss;//exchange between target and projectile if they are electrons |
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| 160 | else eloss=0.5*kineticEnergy; |
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| 161 | } |
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| 162 | G4double ee = kineticEnergy - 0.5*eloss; |
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| 163 | G4double ttau = ee/electron_mass_c2; |
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| 164 | G4double ttau2 = ttau*ttau; |
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| 165 | G4double epsilonpp= eloss/ee; |
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| 166 | G4double cst1=epsilonpp*epsilonpp*(6+10*ttau+5*ttau2)/(24*ttau2+48*ttau+72); |
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| 167 | |
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| 168 | kineticEnergy *= (1 - cst1); |
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| 169 | /////////////////////////////////////////// |
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| 170 | // additivity rule for mixture and compound xsection's |
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| 171 | const G4Material* mat = currentCouple->GetMaterial(); |
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| 172 | const G4ElementVector* theElementVector = mat->GetElementVector(); |
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| 173 | const G4double* theAtomNumDensityVector = mat->GetVecNbOfAtomsPerVolume(); |
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| 174 | G4int nelm = mat->GetNumberOfElements(); |
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| 175 | G4double s0,s1; |
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| 176 | lambda0=0.; |
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| 177 | for(G4int i=0;i<nelm;i++) |
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| 178 | { |
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| 179 | CalculateIntegrals(particle,(*theElementVector)[i]->GetZ(),kineticEnergy,s0,s1); |
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| 180 | lambda0 += (theAtomNumDensityVector[i]*s0); |
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| 181 | } |
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| 182 | if(lambda0>DBL_MIN) lambda0 =1./lambda0; |
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| 183 | |
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| 184 | // Newton-Raphson root's finding method of scrA from: |
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| 185 | // Sig1(PWA)/Sig0(PWA)=g1=2*scrA*((1+scrA)*log(1+1/scrA)-1) |
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| 186 | G4double g1=0.0; |
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| 187 | if(lambda1>DBL_MIN) g1 = lambda0/lambda1; |
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| 188 | |
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| 189 | G4double logx0,x1,delta; |
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| 190 | G4double x0=g1/2.; |
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| 191 | do |
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| 192 | { |
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| 193 | logx0=std::log(1.+1./x0); |
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| 194 | x1 = x0-(x0*((1.+x0)*logx0-1.0)-g1/2.)/( (1.+2.*x0)*logx0-2.0); |
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| 195 | delta = std::abs( x1 - x0 ); |
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| 196 | x0 = x1; |
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| 197 | } while (delta > 1.0e-12); |
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| 198 | G4double scrA = x1; |
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| 199 | |
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| 200 | G4double lambdan=0.; |
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| 201 | |
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| 202 | if(lambda0>0.)lambdan=tPathLength/lambda0; |
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| 203 | if(lambdan<=1.0e-12)return; |
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| 204 | G4double lambdan12=0.5*lambdan; |
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| 205 | Qn1 = lambdan *g1;//2.* lambdan *scrA*((1.+scrA)*log(1.+1./scrA)-1.); |
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| 206 | Qn12 = 0.5*Qn1; |
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| 207 | |
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| 208 | G4double cosTheta1,sinTheta1,cosTheta2,sinTheta2; |
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| 209 | G4double cosPhi1=1.0,sinPhi1=0.0,cosPhi2=1.0,sinPhi2=0.0; |
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| 210 | G4double us=0.0,vs=0.0,ws=1.0,wss=0.,x_coord=0.0,y_coord=0.0,z_coord=1.0; |
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| 211 | |
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| 212 | G4double epsilon1=G4UniformRand(); |
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| 213 | G4double expn = std::exp(-lambdan); |
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| 214 | if(epsilon1<expn)// no scattering |
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| 215 | {return;} |
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| 216 | else if((epsilon1<((1.+lambdan)*expn))||(lambdan<1.))//single scattering (Rutherford DCS's) |
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| 217 | { |
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| 218 | |
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| 219 | G4double xi=G4UniformRand(); |
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| 220 | xi= 2.*scrA*xi/(1.-xi + scrA); |
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| 221 | if(xi<0.)xi=0.; |
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| 222 | else if(xi>2.)xi=2.; |
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| 223 | ws=1.-xi; |
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| 224 | wss=std::sqrt(xi*(2.-xi)); |
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| 225 | G4double phi0=CLHEP::twopi*G4UniformRand(); |
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| 226 | us=wss*cos(phi0); |
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| 227 | vs=wss*sin(phi0); |
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| 228 | } |
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| 229 | else // multiple scattering |
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| 230 | { |
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| 231 | // Ref.2 subsection 4.4 "The best solution found" |
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| 232 | // Sample first substep scattering angle |
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| 233 | SampleCosineTheta(lambdan12,scrA,cosTheta1,sinTheta1); |
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| 234 | G4double phi1 = CLHEP::twopi*G4UniformRand(); |
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| 235 | cosPhi1 = cos(phi1); |
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| 236 | sinPhi1 = sin(phi1); |
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| 237 | |
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| 238 | // Sample second substep scattering angle |
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| 239 | SampleCosineTheta(lambdan12,scrA,cosTheta2,sinTheta2); |
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| 240 | G4double phi2 = CLHEP::twopi*G4UniformRand(); |
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| 241 | cosPhi2 = cos(phi2); |
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| 242 | sinPhi2 = sin(phi2); |
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| 243 | |
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| 244 | // Overall scattering direction |
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| 245 | us = sinTheta2*(cosTheta1*cosPhi1*cosPhi2 - sinPhi1*sinPhi2) + cosTheta2*sinTheta1*cosPhi1; |
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| 246 | vs = sinTheta2*(cosTheta1*sinPhi1*cosPhi2 + cosPhi1*sinPhi2) + cosTheta2*sinTheta1*sinPhi1; |
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| 247 | ws = cosTheta1*cosTheta2 - sinTheta1*sinTheta2*cosPhi2; |
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| 248 | G4double sqrtA=sqrt(scrA); |
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| 249 | if(acos(ws)<sqrtA)//small angle approximation for theta less than screening angle |
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| 250 | { |
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| 251 | G4int i=0; |
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| 252 | do{i++; |
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| 253 | ws=1.+Qn12*log(G4UniformRand()); |
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| 254 | }while((fabs(ws)>1.)&&(i<20));//i<20 to avoid time consuming during the run |
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| 255 | if(i>=19)ws=cos(sqrtA); |
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| 256 | |
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| 257 | wss=std::sqrt((1.-ws)*(1.0+ws)); |
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| 258 | us=wss*cos(phi1); |
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| 259 | vs=wss*sin(phi1); |
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| 260 | } |
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| 261 | } |
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| 262 | |
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| 263 | G4ThreeVector oldDirection = dynParticle->GetMomentumDirection(); |
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| 264 | G4ThreeVector newDirection(us,vs,ws); |
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| 265 | newDirection.rotateUz(oldDirection); |
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| 266 | fParticleChange->ProposeMomentumDirection(newDirection); |
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| 267 | |
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| 268 | if((safety > tlimitminfix)&&latDisplasment) |
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| 269 | { |
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| 270 | if(Qn1<0.02)// corresponding to error less than 1% in the exact formula of <z> |
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| 271 | z_coord = 1.0 - Qn1*(0.5 - Qn1/6.); |
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| 272 | else z_coord = (1.-std::exp(-Qn1))/Qn1; |
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| 273 | |
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| 274 | G4double rr=std::sqrt((1.- z_coord*z_coord)/(1.-ws*ws)); |
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| 275 | x_coord = rr*us; |
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| 276 | y_coord = rr*vs; |
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| 277 | // displacement is computed relatively to the end point |
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| 278 | z_coord -= 1.0; |
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| 279 | rr = std::sqrt(x_coord*x_coord+y_coord*y_coord+z_coord*z_coord); |
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| 280 | G4double r = rr*zPathLength; |
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| 281 | /* |
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| 282 | G4cout << "G4GS::SampleSecondaries: e(MeV)= " << kineticEnergy |
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| 283 | << " sinTheta= " << sqrt(1.0 - ws*ws) << " r(mm)= " << r |
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| 284 | << " trueStep(mm)= " << tPathLength |
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| 285 | << " geomStep(mm)= " << zPathLength |
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| 286 | << G4endl; |
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| 287 | */ |
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| 288 | if(tPathLength<=zPathLength)return; |
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| 289 | if(r > tlimitminfix) { |
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| 290 | |
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| 291 | G4ThreeVector Direction(x_coord/rr,y_coord/rr,z_coord/rr); |
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| 292 | Direction.rotateUz(oldDirection); |
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| 293 | |
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| 294 | ComputeDisplacement(fParticleChange, Direction, r, safety); |
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| 295 | } |
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| 296 | } |
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| 297 | } |
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| 298 | |
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| 299 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 300 | |
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| 301 | void |
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| 302 | G4GoudsmitSaundersonMscModel::SampleCosineTheta(G4double lambdan, G4double scrA, |
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| 303 | G4double &cost, G4double &sint) |
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| 304 | { |
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| 305 | G4double xi=0.; |
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| 306 | |
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| 307 | if (Qn12<0.001) |
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| 308 | {G4double r1,tet; |
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| 309 | do{ |
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| 310 | r1=G4UniformRand(); |
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| 311 | xi=-Qn12*log(G4UniformRand()); |
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| 312 | tet=acos(1.-xi); |
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| 313 | }while(tet*r1*r1>sin(tet)); |
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| 314 | } |
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| 315 | else if(Qn12>0.5)xi=2.*G4UniformRand(); |
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| 316 | else xi=2.*(GSTable->SampleTheta(lambdan,scrA,G4UniformRand())); |
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| 317 | |
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| 318 | |
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| 319 | if(xi<0.)xi=0.; |
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| 320 | else if(xi>2.)xi=2.; |
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| 321 | |
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| 322 | cost=(1. - xi); |
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| 323 | sint=sqrt(xi*(2.-xi)); |
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| 324 | |
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| 325 | } |
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| 326 | |
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| 327 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 328 | // Polynomial log-log interpolation of Lambda0 and Lambda1 between 100 eV - 1 GeV |
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| 329 | // linear log-log extrapolation between 1 GeV - 100 TeV |
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| 330 | |
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| 331 | void |
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| 332 | G4GoudsmitSaundersonMscModel::CalculateIntegrals(const G4ParticleDefinition* p,G4double Z, |
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| 333 | G4double kinEnergy,G4double &Sig0, |
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| 334 | G4double &Sig1) |
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| 335 | { |
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| 336 | G4double x1,x2,y1,y2,acoeff,bcoeff; |
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| 337 | G4double kineticE = kinEnergy; |
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| 338 | if(kineticE<lowKEnergy)kineticE=lowKEnergy; |
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| 339 | if(kineticE>highKEnergy)kineticE=highKEnergy; |
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| 340 | kineticE /= eV; |
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| 341 | G4double logE=std::log(kineticE); |
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| 342 | |
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| 343 | G4int iZ = G4int(Z); |
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| 344 | if(iZ > 103) iZ = 103; |
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| 345 | |
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| 346 | G4int enerInd=0; |
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| 347 | for(G4int i=0;i<105;i++) |
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| 348 | { |
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| 349 | if((logE>=ener[i])&&(logE<ener[i+1])){enerInd=i;break;} |
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| 350 | } |
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| 351 | |
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| 352 | if(p==G4Electron::Electron()) |
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| 353 | { |
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| 354 | if(kineticE<=1.0e+9)//Interpolation of the form y=ax²+b |
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| 355 | { |
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| 356 | x1=ener[enerInd]; |
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| 357 | x2=ener[enerInd+1]; |
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| 358 | y1=TCSE[iZ-1][enerInd]; |
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| 359 | y2=TCSE[iZ-1][enerInd+1]; |
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| 360 | acoeff=(y2-y1)/(x2*x2-x1*x1); |
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| 361 | bcoeff=y2-acoeff*x2*x2; |
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| 362 | Sig0=acoeff*logE*logE+bcoeff; |
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| 363 | Sig0 =std::exp(Sig0); |
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| 364 | y1=FTCSE[iZ-1][enerInd]; |
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| 365 | y2=FTCSE[iZ-1][enerInd+1]; |
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| 366 | acoeff=(y2-y1)/(x2*x2-x1*x1); |
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| 367 | bcoeff=y2-acoeff*x2*x2; |
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| 368 | Sig1=acoeff*logE*logE+bcoeff; |
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| 369 | Sig1=std::exp(Sig1); |
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| 370 | } |
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| 371 | else //Interpolation of the form y=ax+b |
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| 372 | { |
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| 373 | x1=ener[104]; |
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| 374 | x2=ener[105]; |
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| 375 | y1=TCSE[iZ-1][104]; |
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| 376 | y2=TCSE[iZ-1][105]; |
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| 377 | Sig0=(y2-y1)*(logE-x1)/(x2-x1)+y1; |
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| 378 | Sig0=std::exp(Sig0); |
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| 379 | y1=FTCSE[iZ-1][104]; |
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| 380 | y2=FTCSE[iZ-1][105]; |
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| 381 | Sig1=(y2-y1)*(logE-x1)/(x2-x1)+y1; |
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| 382 | Sig1=std::exp(Sig1); |
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| 383 | } |
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| 384 | } |
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| 385 | if(p==G4Positron::Positron()) |
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| 386 | { |
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| 387 | if(kinEnergy<=1.0e+9) |
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| 388 | { |
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| 389 | x1=ener[enerInd]; |
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| 390 | x2=ener[enerInd+1]; |
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| 391 | y1=TCSP[iZ-1][enerInd]; |
---|
| 392 | y2=TCSP[iZ-1][enerInd+1]; |
---|
| 393 | acoeff=(y2-y1)/(x2*x2-x1*x1); |
---|
| 394 | bcoeff=y2-acoeff*x2*x2; |
---|
| 395 | Sig0=acoeff*logE*logE+bcoeff; |
---|
| 396 | Sig0 =std::exp(Sig0); |
---|
| 397 | y1=FTCSP[iZ-1][enerInd]; |
---|
| 398 | y2=FTCSP[iZ-1][enerInd+1]; |
---|
| 399 | acoeff=(y2-y1)/(x2*x2-x1*x1); |
---|
| 400 | bcoeff=y2-acoeff*x2*x2; |
---|
| 401 | Sig1=acoeff*logE*logE+bcoeff; |
---|
| 402 | Sig1=std::exp(Sig1); |
---|
| 403 | } |
---|
| 404 | else |
---|
| 405 | { |
---|
| 406 | x1=ener[104]; |
---|
| 407 | x2=ener[105]; |
---|
| 408 | y1=TCSP[iZ-1][104]; |
---|
| 409 | y2=TCSP[iZ-1][105]; |
---|
| 410 | Sig0=(y2-y1)*(logE-x1)/(x2-x1)+y1; |
---|
| 411 | Sig0 =std::exp(Sig0); |
---|
| 412 | y1=FTCSP[iZ-1][104]; |
---|
| 413 | y2=FTCSP[iZ-1][105]; |
---|
| 414 | Sig1=(y2-y1)*(logE-x1)/(x2-x1)+y1; |
---|
| 415 | Sig1=std::exp(Sig1); |
---|
| 416 | } |
---|
| 417 | } |
---|
| 418 | |
---|
| 419 | Sig0 *= barn; |
---|
| 420 | Sig1 *= barn; |
---|
| 421 | |
---|
| 422 | } |
---|
| 423 | |
---|
| 424 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 425 | //t->g->t step transformations taken from Ref.6 |
---|
| 426 | |
---|
| 427 | G4double |
---|
| 428 | G4GoudsmitSaundersonMscModel::ComputeTruePathLengthLimit(const G4Track& track, |
---|
| 429 | G4PhysicsTable* theTable, |
---|
| 430 | G4double currentMinimalStep) |
---|
| 431 | { |
---|
| 432 | tPathLength = currentMinimalStep; |
---|
| 433 | G4StepPoint* sp = track.GetStep()->GetPreStepPoint(); |
---|
| 434 | G4StepStatus stepStatus = sp->GetStepStatus(); |
---|
| 435 | |
---|
| 436 | const G4DynamicParticle* dp = track.GetDynamicParticle(); |
---|
| 437 | |
---|
| 438 | if(stepStatus == fUndefined) { |
---|
| 439 | inside = false; |
---|
| 440 | insideskin = false; |
---|
| 441 | tlimit = geombig; |
---|
| 442 | SetParticle( dp->GetDefinition() ); |
---|
| 443 | } |
---|
| 444 | |
---|
| 445 | theLambdaTable = theTable; |
---|
| 446 | currentCouple = track.GetMaterialCutsCouple(); |
---|
| 447 | currentMaterialIndex = currentCouple->GetIndex(); |
---|
| 448 | currentKinEnergy = dp->GetKineticEnergy(); |
---|
| 449 | currentRange = |
---|
| 450 | theManager->GetRangeFromRestricteDEDX(particle,currentKinEnergy,currentCouple); |
---|
| 451 | |
---|
| 452 | lambda1 = GetLambda(currentKinEnergy); |
---|
| 453 | |
---|
| 454 | // stop here if small range particle |
---|
| 455 | if(inside) return tPathLength; |
---|
| 456 | |
---|
| 457 | if(tPathLength > currentRange) tPathLength = currentRange; |
---|
| 458 | |
---|
| 459 | G4double presafety = sp->GetSafety(); |
---|
| 460 | |
---|
| 461 | //G4cout << "G4GS::StepLimit tPathLength= " |
---|
| 462 | // <<tPathLength<<" safety= " << presafety |
---|
| 463 | // << " range= " <<currentRange<< " lambda= "<<lambda1 |
---|
| 464 | // << " Alg: " << steppingAlgorithm <<G4endl; |
---|
| 465 | |
---|
| 466 | // far from geometry boundary |
---|
| 467 | if(currentRange < presafety) |
---|
| 468 | { |
---|
| 469 | inside = true; |
---|
| 470 | return tPathLength; |
---|
| 471 | } |
---|
| 472 | |
---|
| 473 | // standard version |
---|
| 474 | // |
---|
| 475 | if (steppingAlgorithm == fUseDistanceToBoundary) |
---|
| 476 | { |
---|
| 477 | //compute geomlimit and presafety |
---|
| 478 | G4double geomlimit = ComputeGeomLimit(track, presafety, tPathLength); |
---|
| 479 | |
---|
| 480 | // is far from boundary |
---|
| 481 | if(currentRange <= presafety) |
---|
| 482 | { |
---|
| 483 | inside = true; |
---|
| 484 | return tPathLength; |
---|
| 485 | } |
---|
| 486 | |
---|
| 487 | smallstep += 1.; |
---|
| 488 | insideskin = false; |
---|
| 489 | |
---|
| 490 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
| 491 | { |
---|
| 492 | rangeinit = currentRange; |
---|
| 493 | if(stepStatus == fUndefined) smallstep = 1.e10; |
---|
| 494 | else smallstep = 1.; |
---|
| 495 | |
---|
| 496 | //define stepmin here (it depends on lambda!) |
---|
| 497 | //rough estimation of lambda_elastic/lambda_transport |
---|
| 498 | G4double rat = currentKinEnergy/MeV ; |
---|
| 499 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
| 500 | //stepmin ~ lambda_elastic |
---|
| 501 | stepmin = rat*lambda1; |
---|
| 502 | skindepth = skin*stepmin; |
---|
| 503 | //define tlimitmin |
---|
| 504 | tlimitmin = 10.*stepmin; |
---|
| 505 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
| 506 | |
---|
| 507 | //G4cout << "rangeinit= " << rangeinit << " stepmin= " << stepmin |
---|
| 508 | // << " tlimitmin= " << tlimitmin << " geomlimit= " << geomlimit <<G4endl; |
---|
| 509 | // constraint from the geometry |
---|
| 510 | if((geomlimit < geombig) && (geomlimit > geommin)) |
---|
| 511 | { |
---|
| 512 | if(stepStatus == fGeomBoundary) |
---|
| 513 | tgeom = geomlimit/facgeom; |
---|
| 514 | else |
---|
| 515 | tgeom = 2.*geomlimit/facgeom; |
---|
| 516 | } |
---|
| 517 | else |
---|
| 518 | tgeom = geombig; |
---|
| 519 | |
---|
| 520 | } |
---|
| 521 | |
---|
| 522 | //step limit |
---|
| 523 | tlimit = facrange*rangeinit; |
---|
| 524 | if(tlimit < facsafety*presafety) |
---|
| 525 | tlimit = facsafety*presafety; |
---|
| 526 | |
---|
| 527 | //lower limit for tlimit |
---|
| 528 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 529 | |
---|
| 530 | if(tlimit > tgeom) tlimit = tgeom; |
---|
| 531 | |
---|
| 532 | //G4cout << "tgeom= " << tgeom << " geomlimit= " << geomlimit |
---|
| 533 | // << " tlimit= " << tlimit << " presafety= " << presafety << G4endl; |
---|
| 534 | |
---|
| 535 | // shortcut |
---|
| 536 | if((tPathLength < tlimit) && (tPathLength < presafety) && |
---|
| 537 | (smallstep >= skin) && (tPathLength < geomlimit-0.999*skindepth)) |
---|
| 538 | return tPathLength; |
---|
| 539 | |
---|
| 540 | // step reduction near to boundary |
---|
| 541 | if(smallstep < skin) |
---|
| 542 | { |
---|
| 543 | tlimit = stepmin; |
---|
| 544 | insideskin = true; |
---|
| 545 | } |
---|
| 546 | else if(geomlimit < geombig) |
---|
| 547 | { |
---|
| 548 | if(geomlimit > skindepth) |
---|
| 549 | { |
---|
| 550 | if(tlimit > geomlimit-0.999*skindepth) |
---|
| 551 | tlimit = geomlimit-0.999*skindepth; |
---|
| 552 | } |
---|
| 553 | else |
---|
| 554 | { |
---|
| 555 | insideskin = true; |
---|
| 556 | if(tlimit > stepmin) tlimit = stepmin; |
---|
| 557 | } |
---|
| 558 | } |
---|
| 559 | |
---|
| 560 | if(tlimit < stepmin) tlimit = stepmin; |
---|
| 561 | |
---|
| 562 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
| 563 | |
---|
| 564 | } |
---|
| 565 | // for 'normal' simulation with or without magnetic field |
---|
| 566 | // there no small step/single scattering at boundaries |
---|
| 567 | else if(steppingAlgorithm == fUseSafety) |
---|
| 568 | { |
---|
| 569 | // compute presafety again if presafety <= 0 and no boundary |
---|
| 570 | // i.e. when it is needed for optimization purposes |
---|
| 571 | if((stepStatus != fGeomBoundary) && (presafety < tlimitminfix)) |
---|
| 572 | presafety = ComputeSafety(sp->GetPosition(),tPathLength); |
---|
| 573 | |
---|
| 574 | // is far from boundary |
---|
| 575 | if(currentRange < presafety) |
---|
| 576 | { |
---|
| 577 | inside = true; |
---|
| 578 | return tPathLength; |
---|
| 579 | } |
---|
| 580 | |
---|
| 581 | if((stepStatus == fGeomBoundary) || (stepStatus == fUndefined)) |
---|
| 582 | { |
---|
| 583 | rangeinit = currentRange; |
---|
| 584 | fr = facrange; |
---|
| 585 | // 9.1 like stepping for e+/e- only (not for muons,hadrons) |
---|
| 586 | if(mass < masslimite) |
---|
| 587 | { |
---|
| 588 | if(lambda1 > currentRange) |
---|
| 589 | rangeinit = lambda1; |
---|
| 590 | if(lambda1 > lambdalimit) |
---|
| 591 | fr *= 0.75+0.25*lambda1/lambdalimit; |
---|
| 592 | } |
---|
| 593 | |
---|
| 594 | //lower limit for tlimit |
---|
| 595 | G4double rat = currentKinEnergy/MeV ; |
---|
| 596 | rat = 1.e-3/(rat*(10.+rat)) ; |
---|
| 597 | tlimitmin = 10.*lambda1*rat; |
---|
| 598 | if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix; |
---|
| 599 | } |
---|
| 600 | //step limit |
---|
| 601 | tlimit = fr*rangeinit; |
---|
| 602 | |
---|
| 603 | if(tlimit < facsafety*presafety) |
---|
| 604 | tlimit = facsafety*presafety; |
---|
| 605 | |
---|
| 606 | //lower limit for tlimit |
---|
| 607 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 608 | |
---|
| 609 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
| 610 | } |
---|
| 611 | |
---|
| 612 | // version similar to 7.1 (needed for some experiments) |
---|
| 613 | else |
---|
| 614 | { |
---|
| 615 | if (stepStatus == fGeomBoundary) |
---|
| 616 | { |
---|
| 617 | if (currentRange > lambda1) tlimit = facrange*currentRange; |
---|
| 618 | else tlimit = facrange*lambda1; |
---|
| 619 | |
---|
| 620 | if(tlimit < tlimitmin) tlimit = tlimitmin; |
---|
| 621 | if(tPathLength > tlimit) tPathLength = tlimit; |
---|
| 622 | } |
---|
| 623 | } |
---|
| 624 | //G4cout << "tPathLength= " << tPathLength |
---|
| 625 | // << " currentMinimalStep= " << currentMinimalStep << G4endl; |
---|
| 626 | return tPathLength ; |
---|
| 627 | } |
---|
| 628 | |
---|
| 629 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 630 | // taken from Ref.6 |
---|
| 631 | G4double G4GoudsmitSaundersonMscModel::ComputeGeomPathLength(G4double) |
---|
| 632 | { |
---|
| 633 | par1 = -1. ; |
---|
| 634 | par2 = par3 = 0. ; |
---|
| 635 | |
---|
| 636 | // do the true -> geom transformation |
---|
| 637 | zPathLength = tPathLength; |
---|
| 638 | |
---|
| 639 | // z = t for very small tPathLength |
---|
| 640 | if(tPathLength < tlimitminfix) return zPathLength; |
---|
| 641 | |
---|
| 642 | // this correction needed to run MSC with eIoni and eBrem inactivated |
---|
| 643 | // and makes no harm for a normal run |
---|
| 644 | if(tPathLength > currentRange) |
---|
| 645 | tPathLength = currentRange ; |
---|
| 646 | |
---|
| 647 | G4double tau = tPathLength/lambda1 ; |
---|
| 648 | |
---|
| 649 | if ((tau <= tausmall) || insideskin) { |
---|
| 650 | zPathLength = tPathLength; |
---|
| 651 | if(zPathLength > lambda1) zPathLength = lambda1; |
---|
| 652 | return zPathLength; |
---|
| 653 | } |
---|
| 654 | |
---|
| 655 | G4double zmean = tPathLength; |
---|
| 656 | if (tPathLength < currentRange*dtrl) { |
---|
| 657 | if(tau < taulim) zmean = tPathLength*(1.-0.5*tau) ; |
---|
| 658 | else zmean = lambda1*(1.-exp(-tau)); |
---|
| 659 | } else if(currentKinEnergy < mass) { |
---|
| 660 | par1 = 1./currentRange ; |
---|
| 661 | par2 = 1./(par1*lambda1) ; |
---|
| 662 | par3 = 1.+par2 ; |
---|
| 663 | if(tPathLength < currentRange) |
---|
| 664 | zmean = (1.-exp(par3*log(1.-tPathLength/currentRange)))/(par1*par3) ; |
---|
| 665 | else |
---|
| 666 | zmean = 1./(par1*par3) ; |
---|
| 667 | } else { |
---|
| 668 | G4double T1 = theManager->GetEnergy(particle,currentRange-tPathLength, |
---|
| 669 | currentCouple); |
---|
| 670 | |
---|
| 671 | lambda11 = GetLambda(T1); |
---|
| 672 | |
---|
| 673 | par1 = (lambda1-lambda11)/(lambda1*tPathLength) ; |
---|
| 674 | par2 = 1./(par1*lambda1) ; |
---|
| 675 | par3 = 1.+par2 ; |
---|
| 676 | zmean = (1.-exp(par3*log(lambda11/lambda1)))/(par1*par3) ; |
---|
| 677 | } |
---|
| 678 | |
---|
| 679 | zPathLength = zmean ; |
---|
| 680 | // sample z |
---|
| 681 | if(samplez) { |
---|
| 682 | |
---|
| 683 | const G4double ztmax = 0.99; |
---|
| 684 | G4double zt = zmean/tPathLength ; |
---|
| 685 | |
---|
| 686 | if (tPathLength > stepmin && zt < ztmax) { |
---|
| 687 | |
---|
| 688 | G4double u,cz1; |
---|
| 689 | if(zt >= 0.333333333) { |
---|
| 690 | |
---|
| 691 | G4double cz = 0.5*(3.*zt-1.)/(1.-zt) ; |
---|
| 692 | cz1 = 1.+cz ; |
---|
| 693 | G4double u0 = cz/cz1 ; |
---|
| 694 | G4double grej ; |
---|
| 695 | do { |
---|
| 696 | u = exp(log(G4UniformRand())/cz1) ; |
---|
| 697 | grej = exp(cz*log(u/u0))*(1.-u)/(1.-u0) ; |
---|
| 698 | } while (grej < G4UniformRand()) ; |
---|
| 699 | |
---|
| 700 | } else { |
---|
| 701 | cz1 = 1./zt-1.; |
---|
| 702 | u = 1.-exp(log(G4UniformRand())/cz1) ; |
---|
| 703 | } |
---|
| 704 | zPathLength = tPathLength*u ; |
---|
| 705 | } |
---|
| 706 | } |
---|
| 707 | if(zPathLength > lambda1) zPathLength = lambda1; |
---|
| 708 | //G4cout << "zPathLength= " << zPathLength << " lambda1= " << lambda1 << G4endl; |
---|
| 709 | |
---|
| 710 | return zPathLength; |
---|
| 711 | } |
---|
| 712 | |
---|
| 713 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 714 | // taken from Ref.6 |
---|
| 715 | G4double |
---|
| 716 | G4GoudsmitSaundersonMscModel::ComputeTrueStepLength(G4double geomStepLength) |
---|
| 717 | { |
---|
| 718 | // step defined other than transportation |
---|
| 719 | if(geomStepLength == zPathLength && tPathLength <= currentRange) |
---|
| 720 | return tPathLength; |
---|
| 721 | |
---|
| 722 | // t = z for very small step |
---|
| 723 | zPathLength = geomStepLength; |
---|
| 724 | tPathLength = geomStepLength; |
---|
| 725 | if(geomStepLength < tlimitminfix) return tPathLength; |
---|
| 726 | |
---|
| 727 | // recalculation |
---|
| 728 | if((geomStepLength > lambda1*tausmall) && !insideskin) |
---|
| 729 | { |
---|
| 730 | if(par1 < 0.) |
---|
| 731 | tPathLength = -lambda1*log(1.-geomStepLength/lambda1) ; |
---|
| 732 | else |
---|
| 733 | { |
---|
| 734 | if(par1*par3*geomStepLength < 1.) |
---|
| 735 | tPathLength = (1.-exp(log(1.-par1*par3*geomStepLength)/par3))/par1 ; |
---|
| 736 | else |
---|
| 737 | tPathLength = currentRange; |
---|
| 738 | } |
---|
| 739 | } |
---|
| 740 | if(tPathLength < geomStepLength) tPathLength = geomStepLength; |
---|
| 741 | //G4cout << "tPathLength= " << tPathLength << " step= " << geomStepLength << G4endl; |
---|
| 742 | |
---|
| 743 | return tPathLength; |
---|
| 744 | } |
---|
| 745 | |
---|
| 746 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 747 | //Total & first transport x sections for e-/e+ generated from ELSEPA code |
---|
| 748 | |
---|
| 749 | void G4GoudsmitSaundersonMscModel::LoadELSEPAXSections() |
---|
| 750 | { |
---|
| 751 | G4String filename = "XSECTIONS.dat"; |
---|
| 752 | |
---|
| 753 | char* path = getenv("G4LEDATA"); |
---|
| 754 | if (!path) |
---|
| 755 | { |
---|
| 756 | G4String excep = "G4GoudsmitSaundersonTable: G4LEDATA environment variable not set properly"; |
---|
| 757 | G4Exception(excep); |
---|
| 758 | } |
---|
| 759 | |
---|
| 760 | G4String pathString(path); |
---|
| 761 | G4String dirFile = pathString + "/msc_GS/" + filename; |
---|
| 762 | FILE *infile; |
---|
| 763 | infile = fopen(dirFile,"r"); |
---|
| 764 | if (infile == 0) |
---|
| 765 | { |
---|
| 766 | G4String excep = "G4GoudsmitSaunderson - data files: " + dirFile + " not found"; |
---|
| 767 | G4Exception(excep); |
---|
| 768 | } |
---|
| 769 | |
---|
| 770 | // Read parameters from tables and take logarithms |
---|
| 771 | G4float aRead; |
---|
| 772 | for(G4int i=0 ; i<106 ;i++){ |
---|
| 773 | fscanf(infile,"%f\t",&aRead); |
---|
| 774 | if(aRead > 0.0) aRead = log(aRead); |
---|
| 775 | else aRead = 0.0; |
---|
| 776 | ener[i]=aRead; |
---|
| 777 | } |
---|
| 778 | for(G4int j=0;j<103;j++){ |
---|
| 779 | for(G4int i=0;i<106;i++){ |
---|
| 780 | fscanf(infile,"%f\t",&aRead); |
---|
| 781 | if(aRead > 0.0) aRead = log(aRead); |
---|
| 782 | else aRead = 0.0; |
---|
| 783 | TCSE[j][i]=aRead; |
---|
| 784 | } |
---|
| 785 | } |
---|
| 786 | for(G4int j=0;j<103;j++){ |
---|
| 787 | for(G4int i=0;i<106;i++){ |
---|
| 788 | fscanf(infile,"%f\t",&aRead); |
---|
| 789 | if(aRead > 0.0) aRead = log(aRead); |
---|
| 790 | else aRead = 0.0; |
---|
| 791 | FTCSE[j][i]=aRead; |
---|
| 792 | } |
---|
| 793 | } |
---|
| 794 | for(G4int j=0;j<103;j++){ |
---|
| 795 | for(G4int i=0;i<106;i++){ |
---|
| 796 | fscanf(infile,"%f\t",&aRead); |
---|
| 797 | if(aRead > 0.0) aRead = log(aRead); |
---|
| 798 | else aRead = 0.0; |
---|
| 799 | TCSP[j][i]=aRead; |
---|
| 800 | } |
---|
| 801 | } |
---|
| 802 | for(G4int j=0;j<103;j++){ |
---|
| 803 | for(G4int i=0;i<106;i++){ |
---|
| 804 | fscanf(infile,"%f\t",&aRead); |
---|
| 805 | if(aRead > 0.0) aRead = log(aRead); |
---|
| 806 | else aRead = 0.0; |
---|
| 807 | FTCSP[j][i]=aRead; |
---|
| 808 | } |
---|
| 809 | } |
---|
| 810 | |
---|
| 811 | fclose(infile); |
---|
| 812 | |
---|
| 813 | } |
---|
| 814 | |
---|
| 815 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|