// // ******************************************************************** // * License and Disclaimer * // * * // * The Geant4 software is copyright of the Copyright Holders of * // * the Geant4 Collaboration. It is provided under the terms and * // * conditions of the Geant4 Software License, included in the file * // * LICENSE and available at http://cern.ch/geant4/license . These * // * include a list of copyright holders. * // * * // * Neither the authors of this software system, nor their employing * // * institutes,nor the agencies providing financial support for this * // * work make any representation or warranty, express or implied, * // * regarding this software system or assume any liability for its * // * use. Please see the license in the file LICENSE and URL above * // * for the full disclaimer and the limitation of liability. * // * * // * This code implementation is the result of the scientific and * // * technical work of the GEANT4 collaboration. * // * By using, copying, modifying or distributing the software (or * // * any work based on the software) you agree to acknowledge its * // * use in resulting scientific publications, and indicate your * // * acceptance of all terms of the Geant4 Software license. * // ******************************************************************** // // // $Id: G4SynchrotronRadiation.cc,v 1.8 2010/10/14 18:38:21 vnivanch Exp $ // GEANT4 tag $Name: geant4-09-04 $ // // -------------------------------------------------------------- // GEANT 4 class implementation file // CERN Geneva Switzerland // // History: first implementation, // 21-5-98 V.Grichine // 28-05-01, V.Ivanchenko minor changes to provide ANSI -wall compilation // 04.03.05, V.Grichine: get local field interface // 18-05-06 H. Burkhardt: Energy spectrum from function rather than table // // // // /////////////////////////////////////////////////////////////////////////// #include "G4SynchrotronRadiation.hh" #include "G4UnitsTable.hh" #include "G4EmProcessSubType.hh" /////////////////////////////////////////////////////////////////////// // // Constructor // G4SynchrotronRadiation::G4SynchrotronRadiation(const G4String& processName, G4ProcessType type):G4VDiscreteProcess (processName, type), theGamma (G4Gamma::Gamma() ), theElectron ( G4Electron::Electron() ), thePositron ( G4Positron::Positron() ) { G4TransportationManager* transportMgr = G4TransportationManager::GetTransportationManager(); fFieldPropagator = transportMgr->GetPropagatorInField(); fLambdaConst = std::sqrt(3.0)*electron_mass_c2/ (2.5*fine_structure_const*eplus*c_light) ; fEnergyConst = 1.5*c_light*c_light*eplus*hbar_Planck/electron_mass_c2 ; SetProcessSubType(fSynchrotronRadiation); verboseLevel=1; } ///////////////////////////////////////////////////////////////////////// // // Destructor // G4SynchrotronRadiation::~G4SynchrotronRadiation() {} /////////////////////////////// METHODS ///////////////////////////////// // // // Production of synchrotron X-ray photon // GEANT4 internal units. // G4double G4SynchrotronRadiation::GetMeanFreePath( const G4Track& trackData, G4double, G4ForceCondition* condition) { // gives the MeanFreePath in GEANT4 internal units G4double MeanFreePath; const G4DynamicParticle* aDynamicParticle = trackData.GetDynamicParticle(); *condition = NotForced ; G4double gamma = aDynamicParticle->GetTotalEnergy()/ aDynamicParticle->GetMass(); G4double particleCharge = aDynamicParticle->GetDefinition()->GetPDGCharge(); if ( gamma < 1.0e3 ) MeanFreePath = DBL_MAX; else { G4ThreeVector FieldValue; const G4Field* pField = 0; G4FieldManager* fieldMgr=0; G4bool fieldExertsForce = false; if( (particleCharge != 0.0) ) { fieldMgr = fFieldPropagator->FindAndSetFieldManager( trackData.GetVolume() ); if ( fieldMgr != 0 ) { // If the field manager has no field, there is no field ! fieldExertsForce = ( fieldMgr->GetDetectorField() != 0 ); } } if ( fieldExertsForce ) { pField = fieldMgr->GetDetectorField() ; G4ThreeVector globPosition = trackData.GetPosition(); G4double globPosVec[4], FieldValueVec[6]; globPosVec[0] = globPosition.x(); globPosVec[1] = globPosition.y(); globPosVec[2] = globPosition.z(); globPosVec[3] = trackData.GetGlobalTime(); pField->GetFieldValue( globPosVec, FieldValueVec ); FieldValue = G4ThreeVector( FieldValueVec[0], FieldValueVec[1], FieldValueVec[2] ); G4ThreeVector unitMomentum = aDynamicParticle->GetMomentumDirection(); G4ThreeVector unitMcrossB = FieldValue.cross(unitMomentum) ; G4double perpB = unitMcrossB.mag() ; if( perpB > 0.0 ) MeanFreePath = fLambdaConst/perpB; else MeanFreePath = DBL_MAX; static G4bool FirstTime=true; if(verboseLevel > 0 && FirstTime) { G4cout << "G4SynchrotronRadiation::GetMeanFreePath :" << '\n' << std::setprecision(4) << " MeanFreePath = " << G4BestUnit(MeanFreePath, "Length") << G4endl; if(verboseLevel > 1) { G4ThreeVector pvec=aDynamicParticle->GetMomentum(); G4double Btot=FieldValue.getR(); G4double ptot=pvec.getR(); G4double rho= ptot / (MeV * c_light * Btot ); // full bending radius G4double Theta=unitMomentum.theta(FieldValue); // angle between particle and field G4cout << " B = " << Btot/tesla << " Tesla" << " perpB = " << perpB/tesla << " Tesla" << " Theta = " << Theta << " std::sin(Theta)=" << std::sin(Theta) << '\n' << " ptot = " << G4BestUnit(ptot,"Energy") << " rho = " << G4BestUnit(rho,"Length") << G4endl; } FirstTime=false; } } else MeanFreePath = DBL_MAX; } return MeanFreePath; } //////////////////////////////////////////////////////////////////////////////// // // G4VParticleChange* G4SynchrotronRadiation::PostStepDoIt(const G4Track& trackData, const G4Step& stepData ) { aParticleChange.Initialize(trackData); const G4DynamicParticle* aDynamicParticle=trackData.GetDynamicParticle(); G4double gamma = aDynamicParticle->GetTotalEnergy()/ (aDynamicParticle->GetMass() ); if(gamma <= 1.0e3 ) { return G4VDiscreteProcess::PostStepDoIt(trackData,stepData); } G4double particleCharge = aDynamicParticle->GetDefinition()->GetPDGCharge(); G4ThreeVector FieldValue; const G4Field* pField = 0 ; G4FieldManager* fieldMgr=0; G4bool fieldExertsForce = false; if( (particleCharge != 0.0) ) { fieldMgr = fFieldPropagator->FindAndSetFieldManager( trackData.GetVolume() ); if ( fieldMgr != 0 ) { // If the field manager has no field, there is no field ! fieldExertsForce = ( fieldMgr->GetDetectorField() != 0 ); } } if ( fieldExertsForce ) { pField = fieldMgr->GetDetectorField() ; G4ThreeVector globPosition = trackData.GetPosition() ; G4double globPosVec[4], FieldValueVec[6] ; globPosVec[0] = globPosition.x() ; globPosVec[1] = globPosition.y() ; globPosVec[2] = globPosition.z() ; globPosVec[3] = trackData.GetGlobalTime(); pField->GetFieldValue( globPosVec, FieldValueVec ) ; FieldValue = G4ThreeVector( FieldValueVec[0], FieldValueVec[1], FieldValueVec[2] ); G4ThreeVector unitMomentum = aDynamicParticle->GetMomentumDirection(); G4ThreeVector unitMcrossB = FieldValue.cross(unitMomentum); G4double perpB = unitMcrossB.mag() ; if(perpB > 0.0) { // M-C of synchrotron photon energy G4double energyOfSR = GetRandomEnergySR(gamma,perpB); // check against insufficient energy if( energyOfSR <= 0.0 ) { return G4VDiscreteProcess::PostStepDoIt(trackData,stepData); } G4double kineticEnergy = aDynamicParticle->GetKineticEnergy(); G4ParticleMomentum particleDirection = aDynamicParticle->GetMomentumDirection(); // M-C of its direction G4double Teta = G4UniformRand()/gamma ; // Very roughly G4double Phi = twopi * G4UniformRand() ; G4double dirx = std::sin(Teta)*std::cos(Phi) , diry = std::sin(Teta)*std::sin(Phi) , dirz = std::cos(Teta) ; G4ThreeVector gammaDirection ( dirx, diry, dirz); gammaDirection.rotateUz(particleDirection); // polarization of new gamma // G4double sx = std::cos(Teta)*std::cos(Phi); // G4double sy = std::cos(Teta)*std::sin(Phi); // G4double sz = -std::sin(Teta); G4ThreeVector gammaPolarization = FieldValue.cross(gammaDirection); gammaPolarization = gammaPolarization.unit(); // (sx, sy, sz); // gammaPolarization.rotateUz(particleDirection); // create G4DynamicParticle object for the SR photon G4DynamicParticle* aGamma= new G4DynamicParticle ( theGamma, gammaDirection, energyOfSR ); aGamma->SetPolarization( gammaPolarization.x(), gammaPolarization.y(), gammaPolarization.z() ); aParticleChange.SetNumberOfSecondaries(1); aParticleChange.AddSecondary(aGamma); // Update the incident particle G4double newKinEnergy = kineticEnergy - energyOfSR ; aParticleChange.ProposeLocalEnergyDeposit (0.); if (newKinEnergy > 0.) { aParticleChange.ProposeMomentumDirection( particleDirection ); aParticleChange.ProposeEnergy( newKinEnergy ); } else { aParticleChange.ProposeEnergy( 0. ); } } } return G4VDiscreteProcess::PostStepDoIt(trackData,stepData); } ///////////////////////////////////////////////////////////////////////////////// // // G4double G4SynchrotronRadiation::InvSynFracInt(G4double x) // direct generation { // from 0 to 0.7 const G4double aa1=0 ,aa2=0.7; const G4int ncheb1=27; static const G4double cheb1[] = { 1.22371665676046468821,0.108956475422163837267,0.0383328524358594396134,0.00759138369340257753721, 0.00205712048644963340914,0.000497810783280019308661,0.000130743691810302187818,0.0000338168760220395409734, 8.97049680900520817728e-6,2.38685472794452241466e-6,6.41923109149104165049e-7,1.73549898982749277843e-7, 4.72145949240790029153e-8,1.29039866111999149636e-8,3.5422080787089834182e-9,9.7594757336403784905e-10, 2.6979510184976065731e-10,7.480422622550977077e-11,2.079598176402699913e-11,5.79533622220841193e-12, 1.61856011449276096e-12,4.529450993473807e-13,1.2698603951096606e-13,3.566117394511206e-14,1.00301587494091e-14, 2.82515346447219e-15,7.9680747949792e-16}; // from 0.7 to 0.9132260271183847 const G4double aa3=0.9132260271183847; const G4int ncheb2=27; static const G4double cheb2[] = { 1.1139496701107756,0.3523967429328067,0.0713849171926623,0.01475818043595387,0.003381255637322462, 0.0008228057599452224,0.00020785506681254216,0.00005390169253706556,0.000014250571923902464,3.823880733161044e-6, 1.0381966089136036e-6,2.8457557457837253e-7,7.86223332179956e-8,2.1866609342508474e-8,6.116186259857143e-9, 1.7191233618437565e-9,4.852755117740807e-10,1.3749966961763457e-10,3.908961987062447e-11,1.1146253766895824e-11, 3.1868887323415814e-12,9.134319791300977e-13,2.6211077371181566e-13,7.588643377757906e-14,2.1528376972619e-14, 6.030906040404772e-15,1.9549163926819867e-15}; // Chebyshev with exp/log scale // a = -Log[1 - SynFracInt[1]]; b = -Log[1 - SynFracInt[7]]; const G4double aa4=2.4444485538746025480,aa5=9.3830728608909477079; const G4int ncheb3=28; static const G4double cheb3[] = { 1.2292683840435586977,0.160353449247864455879,-0.0353559911947559448721,0.00776901561223573936985, -0.00165886451971685133259,0.000335719118906954279467,-0.0000617184951079161143187,9.23534039743246708256e-6, -6.06747198795168022842e-7,-3.07934045961999778094e-7,1.98818772614682367781e-7,-8.13909971567720135413e-8, 2.84298174969641838618e-8,-9.12829766621316063548e-9,2.77713868004820551077e-9,-8.13032767247834023165e-10, 2.31128525568385247392e-10,-6.41796873254200220876e-11,1.74815310473323361543e-11,-4.68653536933392363045e-12, 1.24016595805520752748e-12,-3.24839432979935522159e-13,8.44601465226513952994e-14,-2.18647276044246803998e-14, 5.65407548745690689978e-15,-1.46553625917463067508e-15,3.82059606377570462276e-16,-1.00457896653436912508e-16}; const G4double aa6=33.122936966163038145; const G4int ncheb4=27; static const G4double cheb4[] = {1.69342658227676741765,0.0742766400841232319225,-0.019337880608635717358,0.00516065527473364110491, -0.00139342012990307729473,0.000378549864052022522193,-0.000103167085583785340215,0.0000281543441271412178337, -7.68409742018258198651e-6,2.09543221890204537392e-6,-5.70493140367526282946e-7,1.54961164548564906446e-7, -4.19665599629607704794e-8,1.13239680054166507038e-8,-3.04223563379021441863e-9,8.13073745977562957997e-10, -2.15969415476814981374e-10,5.69472105972525594811e-11,-1.48844799572430829499e-11,3.84901514438304484973e-12, -9.82222575944247161834e-13,2.46468329208292208183e-13,-6.04953826265982691612e-14,1.44055805710671611984e-14, -3.28200813577388740722e-15,6.96566359173765367675e-16,-1.294122794852896275e-16}; if(x 0 && FirstTime) { G4double Emean=8./(15.*std::sqrt(3.))*Ecr; // mean photon energy G4double E_rms=std::sqrt(211./675.)*Ecr; // rms of photon energy distribution G4cout << "G4SynchrotronRadiation::GetRandomEnergySR :" << '\n' << std::setprecision(4) << " Ecr = " << G4BestUnit(Ecr,"Energy") << '\n' << " Emean = " << G4BestUnit(Emean,"Energy") << '\n' << " E_rms = " << G4BestUnit(E_rms,"Energy") << G4endl; FirstTime=false; } G4double energySR=Ecr*InvSynFracInt(G4UniformRand()); return energySR; } void G4SynchrotronRadiation::BuildPhysicsTable(const G4ParticleDefinition& part) { if(0 < verboseLevel && &part==theElectron ) PrintInfoDefinition(); } void G4SynchrotronRadiation::PrintInfoDefinition() // not yet called, usually called from BuildPhysicsTable { G4String comments ="Incoherent Synchrotron Radiation\n"; G4cout << G4endl << GetProcessName() << ": " << comments << " good description for long magnets at all energies" << G4endl; } ///////////////////// end of G4SynchrotronRadiation.cc