Gabriele Cosmo
204 lines
6.9 KiB
C++
204 lines
6.9 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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//
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// -------------------------------------------------------------------
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//
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// GEANT4 Class file
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//
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//
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// File name: G4ionEffectiveCharge
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//
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// Author: Vladimir Ivanchenko
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//
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// Creation date: 07.05.2002
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//
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// Modifications:
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// 12.09.2004 Set low energy limit to 1 keV (V.Ivanchenko)
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// 25.01.2005 Add protection - min Charge 0.1 eplus (V.Ivanchenko)
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// 28.04.2006 Set upper energy limit to 50 MeV (V.Ivanchenko)
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// 23.05.2006 Set upper energy limit to Z*10 MeV (V.Ivanchenko)
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// 15.08.2006 Add protection for not defined material (V.Ivanchenko)
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// 27-09-2007 Use Fermi energy from material, optimazed formulas (V.Ivanchenko)
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//
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// -------------------------------------------------------------------
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//
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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#include "G4ionEffectiveCharge.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4SystemOfUnits.hh"
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#include "G4UnitsTable.hh"
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#include "G4Material.hh"
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#include "G4NistManager.hh"
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#include "G4Log.hh"
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#include "G4Exp.hh"
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#include "G4Pow.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4ionEffectiveCharge::G4ionEffectiveCharge()
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{
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chargeCorrection = 1.0;
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energyHighLimit = 20.0*MeV;
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energyLowLimit = 1.0*keV;
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energyBohr = 25.*keV;
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massFactor = amu_c2/(proton_mass_c2*keV);
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minCharge = 1.0;
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lastPart = 0;
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lastMat = 0;
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lastKinEnergy = 0.0;
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effCharge = eplus;
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inveplus = 1.0/CLHEP::eplus;
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g4calc = G4Pow::GetInstance();
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4ionEffectiveCharge::~G4ionEffectiveCharge()
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{}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4ionEffectiveCharge::EffectiveCharge(const G4ParticleDefinition* p,
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const G4Material* material,
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G4double kineticEnergy)
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{
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if(p == lastPart && material == lastMat && kineticEnergy == lastKinEnergy)
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return effCharge;
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lastPart = p;
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lastMat = material;
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lastKinEnergy = kineticEnergy;
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G4double mass = p->GetPDGMass();
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G4double charge = p->GetPDGCharge();
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G4double Zi = charge*inveplus;
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chargeCorrection = 1.0;
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effCharge = charge;
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// The aproximation of ion effective charge from:
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// J.F.Ziegler, J.P. Biersack, U. Littmark
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// The Stopping and Range of Ions in Matter,
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// Vol.1, Pergamon Press, 1985
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// Fast ions or hadrons
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G4double reducedEnergy = kineticEnergy * proton_mass_c2/mass ;
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//G4cout << "e= " << reducedEnergy << " Zi= " << Zi << " "
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//<< material->GetName() << G4endl;
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if(Zi < 1.5 || !material || reducedEnergy > Zi*energyHighLimit ) {
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return charge;
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}
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G4double z = material->GetIonisation()->GetZeffective();
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reducedEnergy = std::max(reducedEnergy,energyLowLimit);
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// Helium ion case
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if( Zi < 2.5 ) {
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static const G4double c[6] =
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{0.2865,0.1266,-0.001429,0.02402,-0.01135,0.001475};
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G4double Q = std::max(0.0,G4Log(reducedEnergy*massFactor));
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G4double x = c[0];
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G4double y = 1.0;
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for (G4int i=1; i<6; ++i) {
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y *= Q;
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x += y * c[i] ;
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}
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G4double ex;
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if(x < 0.2) { ex = x * (1 - 0.5*x); }
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else { ex = 1. - G4Exp(-x); }
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G4double tq = 7.6 - Q;
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G4double tq2= tq*tq;
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G4double tt = ( 0.007 + 0.00005 * z );
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if(tq2 < 0.2) { tt *= (1.0 - tq2 + 0.5*tq2*tq2); }
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else { tt *= G4Exp(-tq2); }
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effCharge = charge*(1.0 + tt) * std::sqrt(ex);
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// Heavy ion case
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} else {
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G4double y;
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G4double zi13 = g4calc->A13(Zi);
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G4double zi23 = zi13*zi13;
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// v1 is ion velocity in vF unit
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G4double eF = material->GetIonisation()->GetFermiEnergy();
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G4double v1sq = reducedEnergy/eF;
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G4double vFsq = eF/energyBohr;
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G4double vF = std::sqrt(eF/energyBohr);
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// Faster than Fermi velocity
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if ( v1sq > 1.0 ) {
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y = vF * std::sqrt(v1sq) * ( 1.0 + 0.2/v1sq ) / zi23 ;
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// Slower than Fermi velocity
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} else {
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y = 0.692308 * vF * (1.0 + 0.666666*v1sq + v1sq*v1sq/15.0) / zi23 ;
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}
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G4double q;
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G4double y3 = std::pow(y, 0.3) ;
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// G4cout<<"y= "<<y<<" y3= "<<y3<<" v1= "<<v1<<" vF= "<<vF<<G4endl;
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q = 1.0 - G4Exp( 0.803*y3 - 1.3167*y3*y3 - 0.38157*y - 0.008983*y*y);
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q = std::max(q, minCharge/Zi);
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effCharge = q*charge;
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G4double tq = 7.6 - G4Log(reducedEnergy/keV);
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G4double tq2= tq*tq;
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G4double sq = 1.0 + ( 0.18 + 0.0015 * z )*G4Exp(-tq2)/ (Zi*Zi);
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// G4cout << "sq= " << sq << G4endl;
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// Screen length according to
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// J.F.Ziegler and J.M.Manoyan, The stopping of ions in compaunds,
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// Nucl. Inst. & Meth. in Phys. Res. B35 (1988) 215-228.
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G4double lambda = 10.0 * vF *g4calc->A23(1.0 - q)/ (zi13 * (6.0 + q));
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G4double lambda2 = lambda*lambda;
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G4double xx = (0.5/q - 0.5)*G4Log(1.0 + lambda2)/vFsq;
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chargeCorrection = sq * (1.0 + xx);
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}
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// G4cout << "G4ionEffectiveCharge: charge= " << charge << " q= " << q
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// << " chargeCor= " << chargeCorrection
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// << " e(MeV)= " << kineticEnergy/MeV << G4endl;
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return effCharge;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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