Gabriele Cosmo
166 lines
6.8 KiB
C++
166 lines
6.8 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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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. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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// * By copying, distributing or modifying the Program (or any work *
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// * based on the Program) you indicate your acceptance of this *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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//
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// $Id: G4Positron.cc,v 1.3.4.2 2001/06/28 20:19:07 gunter Exp $
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// GEANT4 tag $Name: $
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//
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//
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// ----------------------------------------------------------------------
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// GEANT 4 class implementation file
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//
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// History: first implementation, based on object model of
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// 4th April 1996, G.Cosmo
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// **********************************************************************
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// Added particle definitions, H.Kurashige, 19 April 1996
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// Added SetCuts implementation, L.Urban, 12 June 1996
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// Code uses operators (+=, *=, ++, -> etc.) correctly, P. Urban, 26/6/96
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// Add PositronDefinition(), H.Kurashige 4 July 1996
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// ----------------------------------------------------------------------
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#include "g4std/fstream"
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#include "g4std/iomanip"
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#include "G4Positron.hh"
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// ######################################################################
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// ### POSITRON ###
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// ######################################################################
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G4Positron::G4Positron(
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const G4String& aName, G4double mass,
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G4double width, G4double charge,
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G4int iSpin, G4int iParity,
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G4int iConjugation, G4int iIsospin,
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G4int iIsospin3, G4int gParity,
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const G4String& pType, G4int lepton,
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G4int baryon, G4int encoding,
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G4bool stable, G4double lifetime,
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G4DecayTable *decaytable )
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: G4VLepton( aName,mass,width,charge,iSpin,iParity,
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iConjugation,iIsospin,iIsospin3,gParity,pType,
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lepton,baryon,encoding,stable,lifetime,decaytable )
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{
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SetParticleSubType("e");
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}
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// ......................................................................
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// ... static member definitions ...
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// ......................................................................
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//
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// Arguments for constructor are as follows
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// name mass width charge
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// 2*spin parity C-conjugation
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// 2*Isospin 2*Isospin3 G-parity
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// type lepton number baryon number PDG encoding
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// stable lifetime decay table
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G4Positron G4Positron::thePositron(
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"e+", 0.51099906*MeV, 0.0*MeV, +1.*eplus,
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1, 0, 0,
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0, 0, 0,
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"lepton", -1, 0, -11,
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true, -1.0, NULL
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);
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G4Positron* G4Positron::PositronDefinition() {return &thePositron;}
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// initialization for static cut values
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G4double G4Positron::thePositronLengthCut = -1.0;
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G4double* G4Positron::thePositronKineticEnergyCuts = NULL;
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// **********************************************************************
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// ************************* ComputeLoss ********************************
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// **********************************************************************
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G4double G4Positron::ComputeLoss(G4double AtomicNumber,
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G4double KineticEnergy) const
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{
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static G4double Z;
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static G4double taul, ionpot, ionpotlog;
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const G4double cbr1=0.02, cbr2=-5.7e-5, cbr3=1., cbr4=0.072;
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const G4double Tlow=10.*keV, Thigh=1.*GeV;
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static G4double bremfactor = 0.1 ;
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// calculate dE/dx for electrons
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if( abs(AtomicNumber-Z)>0.1 )
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{
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Z = AtomicNumber;
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taul = Tlow/GetPDGMass();
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ionpot = 1.6e-5*MeV*exp(0.9*log(Z))/GetPDGMass();
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ionpotlog = log(ionpot);
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}
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G4double tau = KineticEnergy/GetPDGMass();
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G4double dEdx;
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if(tau<taul)
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{
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G4double t1 = taul+1.;
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G4double t2 = taul+2.;
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G4double tsq = taul*taul;
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G4double beta2 = taul*t2/(t1*t1);
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G4double f = 2.*log(taul)
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-(6.*taul+1.5*tsq-taul*(1.-tsq/3.)/t2-tsq*(0.5-tsq/12.)/
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(t2*t2))/(t1*t1);
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dEdx = (log(2.*taul+4.)-2.*ionpotlog+f)/beta2;
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dEdx = twopi_mc2_rcl2*Z*dEdx;
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G4double clow = dEdx*sqrt(taul);
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dEdx = clow/sqrt(KineticEnergy/GetPDGMass());
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} else {
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G4double t1 = tau+1.;
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G4double t2 = tau+2.;
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G4double tsq = tau*tau;
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G4double beta2 = tau*t2/(t1*t1);
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G4double f = 2.*log(tau)
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- (6.*tau+1.5*tsq-tau*(1.-tsq/3.)/t2-tsq*(0.5-tsq/12.)/
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(t2*t2))/(t1*t1);
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dEdx = (log(2.*tau+4.)-2.*ionpotlog+f)/beta2;
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dEdx = twopi_mc2_rcl2*Z*dEdx;
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// loss from bremsstrahlung follows
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G4double cbrem = (cbr1+cbr2*Z)
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*(cbr3+cbr4*log(KineticEnergy/Thigh));
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cbrem = Z*(Z+1.)*cbrem*tau/beta2;
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cbrem *= bremfactor ;
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dEdx += twopi_mc2_rcl2*cbrem;
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}
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return dEdx;
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}
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// **********************************************************************
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// *********************** BuildRangeVector *****************************
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// **********************************************************************
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void G4Positron::BuildRangeVector(const G4Material* aMaterial,
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const G4LossTable* aLossTable,
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G4double maxEnergy,
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G4double aMass,
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G4PhysicsLogVector* rangeVector)
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{
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G4Electron* pElectron = G4Electron::ElectronDefinition();
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pElectron->BuildRangeVector(aMaterial,
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aLossTable,
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maxEnergy,
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aMass,
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rangeVector);
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}
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