| 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: G4ionEffectiveCharge.cc,v 1.17.2.1 2008/04/22 15:28:13 vnivanch Exp $
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| 27 | // GEANT4 tag $Name: geant4-09-01-patch-02 $
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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 | //
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| 34 | // File name: G4ionEffectiveCharge
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| 35 | //
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| 36 | // Author: Vladimir Ivanchenko
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| 37 | //
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| 38 | // Creation date: 07.05.2002
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| 39 | //
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| 40 | // Modifications:
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| 41 | // 12.09.2004 Set low energy limit to 1 keV (V.Ivanchenko)
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| 42 | // 25.01.2005 Add protection - min Charge 0.1 eplus (V.Ivanchenko)
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| 43 | // 28.04.2006 Set upper energy limit to 50 MeV (V.Ivanchenko)
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| 44 | // 23.05.2006 Set upper energy limit to Z*10 MeV (V.Ivanchenko)
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| 45 | // 15.08.2006 Add protection for not defined material (V.Ivanchenko)
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| 46 | // 27-09-2007 Use Fermi energy from material, optimazed formulas (V.Ivanchenko)
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| 47 | //
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| 48 |
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| 49 | // -------------------------------------------------------------------
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| 50 | //
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| 51 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 52 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 53 |
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| 54 | #include "G4ionEffectiveCharge.hh"
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| 55 | #include "G4UnitsTable.hh"
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| 56 | #include "G4ParticleDefinition.hh"
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| 57 | #include "G4Material.hh"
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| 58 |
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| 59 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 60 |
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| 61 | G4ionEffectiveCharge::G4ionEffectiveCharge()
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| 62 | {
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| 63 | chargeCorrection = 1.0;
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| 64 | energyHighLimit = 10.0*MeV;
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| 65 | energyLowLimit = 1.0*keV;
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| 66 | energyBohr = 25.*keV;
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| 67 | massFactor = amu_c2/(proton_mass_c2*keV);
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| 68 | minCharge = 0.1;
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| 69 | }
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| 70 |
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| 71 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 72 |
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| 73 | G4ionEffectiveCharge::~G4ionEffectiveCharge()
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| 74 | {}
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| 75 |
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| 76 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 77 |
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| 78 | G4double G4ionEffectiveCharge::EffectiveCharge(const G4ParticleDefinition* p,
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| 79 | const G4Material* material,
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| 80 | G4double kineticEnergy)
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| 81 | {
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| 82 | G4double mass = p->GetPDGMass();
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| 83 | G4double charge = p->GetPDGCharge();
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| 84 | G4double Zi = charge/eplus;
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| 85 |
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| 86 | chargeCorrection = 1.0;
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| 87 |
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| 88 | // The aproximation of ion effective charge from:
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| 89 | // J.F.Ziegler, J.P. Biersack, U. Littmark
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| 90 | // The Stopping and Range of Ions in Matter,
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| 91 | // Vol.1, Pergamon Press, 1985
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| 92 | // Fast ions or hadrons
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| 93 | G4double reducedEnergy = kineticEnergy * proton_mass_c2/mass ;
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| 94 | if( reducedEnergy > Zi*energyHighLimit || Zi < 1.5 || !material) return charge;
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| 95 |
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| 96 | static G4double c[6] = {0.2865, 0.1266, -0.001429,
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| 97 | 0.02402,-0.01135, 0.001475} ;
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| 98 |
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| 99 | G4double z = material->GetIonisation()->GetZeffective();
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| 100 | reducedEnergy = std::max(reducedEnergy,energyLowLimit);
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| 101 | G4double q;
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| 102 |
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| 103 | // Helium ion case
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| 104 | if( Zi < 2.5 ) {
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| 105 |
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| 106 | G4double Q = std::max(0.0,std::log(reducedEnergy*massFactor));
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| 107 | G4double x = c[0];
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| 108 | G4double y = 1.0;
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| 109 | for (G4int i=1; i<6; i++) {
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| 110 | y *= Q;
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| 111 | x += y * c[i] ;
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| 112 | }
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| 113 | G4double ex;
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| 114 | if(x < 0.2) ex = x * (1 - 0.5*x);
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| 115 | else ex = 1. - std::exp(-x);
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| 116 |
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| 117 | G4double tq = 7.6 - Q;
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| 118 | G4double tq2= tq*tq;
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| 119 | G4double tt = ( 0.007 + 0.00005 * z );
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| 120 | if(tq2 < 0.2) tt *= (1.0 - tq2 + 0.5*tq2*tq2);
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| 121 | else tt *= std::exp(-tq2);
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| 122 | q = (1.0 + tt) * std::sqrt(ex);
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| 123 |
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| 124 | // Heavy ion case
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| 125 | } else {
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| 126 |
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| 127 | G4double z23 = std::pow(z, 0.666666);
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| 128 | G4double zi13 = std::pow(Zi, 0.333333);
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| 129 | G4double zi23 = zi13*zi13;
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| 130 | G4double e = std::max(reducedEnergy,energyBohr/z23);
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| 131 |
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| 132 | // v1 is ion velocity in vF unit
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| 133 | G4double eF = material->GetIonisation()->GetFermiEnergy();
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| 134 | G4double v1sq = e/eF;
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| 135 | G4double vFsq = eF/energyBohr;
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| 136 | G4double vF = std::sqrt(vFsq);
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| 137 |
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| 138 | G4double y ;
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| 139 |
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| 140 | // Faster than Fermi velocity
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| 141 | if ( v1sq > 1.0 ) {
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| 142 | y = vF * std::sqrt(v1sq) * ( 1.0 + 0.2/v1sq ) / zi23 ;
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| 143 |
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| 144 | // Slower than Fermi velocity
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| 145 | } else {
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| 146 | y = 0.692308 * vF * (1.0 + 0.666666*v1sq + v1sq*v1sq/15.0) / zi23 ;
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| 147 | }
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| 148 |
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| 149 | G4double y3 = std::pow(y, 0.3) ;
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| 150 | // G4cout << "y= " << y << " y3= " << y3 << " v1= " << v1 << " vF= " << vF << G4endl;
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| 151 | q = 1.0 - std::exp( 0.803*y3 - 1.3167*y3*y3 - 0.38157*y - 0.008983*y*y ) ;
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| 152 |
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| 153 | // q = 1.0 - std::exp(-0.95*std::sqrt(reducedEnergy/energyBohr)/zi23);
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| 154 |
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| 155 | G4double qmin = minCharge/Zi;
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| 156 |
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| 157 | if(q < qmin) q = qmin;
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| 158 |
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| 159 | G4double tq = 7.6 - std::log(reducedEnergy/keV);
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| 160 | G4double tq2= tq*tq;
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| 161 | G4double sq = ( 0.18 + 0.0015 * z ) / (Zi*Zi);
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| 162 | if(tq2 < 0.2) sq *= (1.0 - tq2 + 0.5*tq2*tq2);
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| 163 | else sq *= std::exp(-tq2);
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| 164 | sq += 1.0;
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| 165 | // G4cout << "sq= " << sq << G4endl;
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| 166 |
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| 167 | // Screen length according to
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| 168 | // J.F.Ziegler and J.M.Manoyan, The stopping of ions in compaunds,
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| 169 | // Nucl. Inst. & Meth. in Phys. Res. B35 (1988) 215-228.
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| 170 |
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| 171 | G4double lambda = 10.0 * vF / (zi13 * (6.0 + q));
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| 172 | if(q < 0.2) lambda *= (1.0 - 0.666666*q - q*q/9.0);
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| 173 | else lambda *= std::pow(1.0-q, 0.666666);
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| 174 |
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| 175 | G4double lambda2 = lambda*lambda;
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| 176 |
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| 177 | G4double xx = (0.5/q - 0.5)/vFsq;
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| 178 | if(lambda2 < 0.2) xx *= lambda2*(1.0 - 0.5*lambda2);
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| 179 | else xx *= std::log(1.0 + lambda2);
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| 180 |
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| 181 | chargeCorrection = sq * (1.0 + xx);
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| 182 | }
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| 183 | // G4cout << "G4ionEffectiveCharge: charge= " << charge << " q= " << q
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| 184 | // << " chargeCor= " << chargeCorrection
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| 185 | // << " e(MeV)= " << kineticEnergy/MeV << G4endl;
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| 186 | return q*charge;
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| 187 | }
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| 188 |
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| 189 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 190 |
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| 191 |
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