can you tell me all the physics involved in this class (G4EmStandardPhysics\_option3):

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//---------------------------------------------------------------------------
//
// ClassName: G4EmStandardPhysics\_option3
//
// Author: V.Ivanchenko 13.03.2008
//
// Modified:
// 21.04.2008 V.Ivanchenko add long-lived D and B mesons; use spline
// 28.05.2008 V.Ivanchenko linLossLimit=0.01 for ions 0.001 for others
//
//----------------------------------------------------------------------------
//

#include "G4EmStandardPhysics\_option3.hh"

#include "G4SystemOfUnits.hh"
#include "G4ParticleDefinition.hh"
#include "G4LossTableManager.hh"
#include "G4EmParameters.hh"
#include "G4EmBuilder.hh"

#include "G4ComptonScattering.hh"
#include "G4GammaConversion.hh"
#include "G4PhotoElectricEffect.hh"
#include "G4RayleighScattering.hh"
#include "G4PEEffectFluoModel.hh"
#include "G4KleinNishinaModel.hh"
#include "G4LivermorePhotoElectricModel.hh"
#include "G4LivermorePolarizedRayleighModel.hh"
#include "G4PhotoElectricAngularGeneratorPolarized.hh"
#include "G4BetheHeitler5DModel.hh"

#include "G4eMultipleScattering.hh"
#include "G4hMultipleScattering.hh"
#include "G4MscStepLimitType.hh"
#include "G4UrbanMscModel.hh"
#include "G4DummyModel.hh"
#include "G4WentzelVIModel.hh"
#include "G4CoulombScattering.hh"

#include "G4eIonisation.hh"
#include "G4eBremsstrahlung.hh"
#include "G4Generator2BS.hh"
#include "G4SeltzerBergerModel.hh"

#include "G4eplusAnnihilation.hh"
#include "G4UAtomicDeexcitation.hh"

#include "G4ePairProduction.hh"
#include "G4ionIonisation.hh"
#include "G4IonParametrisedLossModel.hh"
#include "G4LindhardSorensenIonModel.hh"
#include "G4IonFluctuations.hh"
#include "G4NuclearStopping.hh"

#include "G4ParticleTable.hh"
#include "G4Gamma.hh"
#include "G4Electron.hh"
#include "G4Positron.hh"
#include "G4GenericIon.hh"

#include "G4PhysicsListHelper.hh"
#include "G4BuilderType.hh"
#include "G4EmModelActivator.hh"
#include "G4GammaGeneralProcess.hh"

// factory
#include "G4PhysicsConstructorFactory.hh"
//
G4\_DECLARE\_PHYSCONSTR\_FACTORY(G4EmStandardPhysics\_option3);

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

G4EmStandardPhysics\_option3::G4EmStandardPhysics\_option3(G4int ver, 
 const G4String&)
 : G4VPhysicsConstructor("G4EmStandard\_opt3")
{
 SetVerboseLevel(ver);
 G4EmParameters\* param = G4EmParameters::Instance();
 param->SetDefaults();
 param->SetVerbose(ver);
 param->SetGeneralProcessActive(true);
 param->SetMinEnergy(10\*CLHEP::eV);
 param->SetLowestElectronEnergy(100\*CLHEP::eV);
 param->SetNumberOfBinsPerDecade(20);
 param->ActivateAngularGeneratorForIonisation(true);
 param->SetUseMottCorrection(true); 
 param->SetStepFunction(0.2, 100\*CLHEP::um);
 param->SetStepFunctionMuHad(0.2, 50\*CLHEP::um);
 param->SetStepFunctionLightIons(0.1, 20\*CLHEP::um);
 param->SetStepFunctionIons(0.1, 1\*CLHEP::um);
 param->SetMscStepLimitType(fUseSafetyPlus);
 param->SetMscRangeFactor(0.03);
 param->SetMuHadLateralDisplacement(true);
 param->SetLateralDisplacementAlg96(true);
 param->SetUseICRU90Data(true);
 param->SetFluctuationType(fUrbanFluctuation);
 param->SetFluo(true);
 param->SetMaxNIELEnergy(1\*CLHEP::MeV);
 SetPhysicsType(bElectromagnetic);
}

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G4EmStandardPhysics\_option3::~G4EmStandardPhysics\_option3()
{}

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void G4EmStandardPhysics\_option3::ConstructParticle()
{
 // minimal set of particles for EM physics
 G4EmBuilder::ConstructMinimalEmSet();
}

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void G4EmStandardPhysics\_option3::ConstructProcess()
{
 if(verboseLevel > 1) {
 G4cout << "### " << GetPhysicsName() << " Construct Processes " << G4endl;
 }
 G4EmBuilder::PrepareEMPhysics();

 G4PhysicsListHelper\* ph = G4PhysicsListHelper::GetPhysicsListHelper();
 G4EmParameters\* param = G4EmParameters::Instance();

 // processes used by several particles
 G4hMultipleScattering\* hmsc = new G4hMultipleScattering("ionmsc");

 // nuclear stopping is enabled if th eenergy limit above zero
 G4double nielEnergyLimit = param->MaxNIELEnergy();
 G4NuclearStopping\* pnuc = nullptr;
 if(nielEnergyLimit > 0.0) {
 pnuc = new G4NuclearStopping();
 pnuc->SetMaxKinEnergy(nielEnergyLimit);
 }

 // Add gamma EM Processes
 G4ParticleDefinition\* particle = G4Gamma::Gamma();

 G4PhotoElectricEffect\* pe = new G4PhotoElectricEffect();
 G4VEmModel\* peModel = new G4LivermorePhotoElectricModel();
 pe->SetEmModel(peModel);
 if(param->EnablePolarisation()) {
 peModel->SetAngularDistribution(new G4PhotoElectricAngularGeneratorPolarized());
 }

 G4ComptonScattering\* cs = new G4ComptonScattering();
 cs->SetEmModel(new G4KleinNishinaModel());

 G4GammaConversion\* gc = new G4GammaConversion();
 if(param->EnablePolarisation()) {
 gc->SetEmModel(new G4BetheHeitler5DModel());
 }

 G4RayleighScattering\* rl = new G4RayleighScattering();
 if(param->EnablePolarisation()) {
 rl->SetEmModel(new G4LivermorePolarizedRayleighModel());
 }

 if(G4EmParameters::Instance()->GeneralProcessActive()) {
 G4GammaGeneralProcess\* sp = new G4GammaGeneralProcess();
 sp->AddEmProcess(pe);
 sp->AddEmProcess(cs);
 sp->AddEmProcess(gc);
 sp->AddEmProcess(rl);
 G4LossTableManager::Instance()->SetGammaGeneralProcess(sp);
 ph->RegisterProcess(sp, particle);
 } else {
 ph->RegisterProcess(pe, particle);
 ph->RegisterProcess(cs, particle);
 ph->RegisterProcess(gc, particle);
 ph->RegisterProcess(rl, particle);
 }

 // e-
 particle = G4Electron::Electron();
 
 G4UrbanMscModel\* msc1 = new G4UrbanMscModel();
 G4EmBuilder::ConstructElectronMscProcess(msc1, nullptr, particle);

 G4eIonisation\* eIoni = new G4eIonisation();

 G4eBremsstrahlung\* brem = new G4eBremsstrahlung();
 G4SeltzerBergerModel\* br1 = new G4SeltzerBergerModel();
 G4eBremsstrahlungRelModel\* br2 = new G4eBremsstrahlungRelModel();
 br1->SetAngularDistribution(new G4Generator2BS());
 br2->SetAngularDistribution(new G4Generator2BS());
 brem->SetEmModel(br1);
 brem->SetEmModel(br2);
 br2->SetLowEnergyLimit(CLHEP::GeV);

 G4ePairProduction\* ee = new G4ePairProduction();

 ph->RegisterProcess(eIoni, particle);
 ph->RegisterProcess(brem, particle);
 ph->RegisterProcess(ee, particle);

 // e+
 particle = G4Positron::Positron();
 
 msc1 = new G4UrbanMscModel();
 G4EmBuilder::ConstructElectronMscProcess(msc1, nullptr, particle);

 eIoni = new G4eIonisation();

 brem = new G4eBremsstrahlung();
 br1 = new G4SeltzerBergerModel();
 br2 = new G4eBremsstrahlungRelModel();
 br1->SetAngularDistribution(new G4Generator2BS());
 br2->SetAngularDistribution(new G4Generator2BS());
 brem->SetEmModel(br1);
 brem->SetEmModel(br2);
 br2->SetLowEnergyLimit(CLHEP::GeV);

 ph->RegisterProcess(eIoni, particle);
 ph->RegisterProcess(brem, particle);
 ph->RegisterProcess(ee, particle);
 ph->RegisterProcess(new G4eplusAnnihilation(), particle);

 // generic ion
 particle = G4GenericIon::GenericIon();
 G4ionIonisation\* ionIoni = new G4ionIonisation();
 auto fluc = new G4IonFluctuations();
 ionIoni->SetFluctModel(fluc);
 ionIoni->SetEmModel(new G4LindhardSorensenIonModel());
 ph->RegisterProcess(hmsc, particle);
 ph->RegisterProcess(ionIoni, particle);
 if(nullptr != pnuc) { ph->RegisterProcess(pnuc, particle); }

 // muons, hadrons, ions
 G4EmBuilder::ConstructCharged(hmsc, pnuc, false);

 // extra configuration
 G4EmModelActivator mact(GetPhysicsName());
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
user
br2->sethighenergylimit(clhep::mev); br1->setlowenergylimit(clhep::gev); br1->sethighenergylimit(clhep::mev); brem->setuserelativisticmodel(true); eioni->setemmodel(br1); eioni->setemmodel(br2); eioni->setlimitenergy(0.001*clhep::mev); g4embuilder::constructelectronprocess(eioni, brem, msc1, nullptr, particle); ph->registerprocess(eioni, particle); ph->registerprocess(brem, particle); // add electron em processes g4particledefinition\* electron = g4electron::electron(); g4emultiplescattering\* emsc = new g4emultiplescattering(); emsc->setsteplimit(new g4mscsteplimittype(1.e-6*clhep::m,1.e-6*clhep::m)); emsc->setemmodel(msc1); g4eionisation\* eion = new g4eionisation(); g4coulombscattering\* coul = new g4coulombscattering(); g4photoelectricangulargenerator\* pegen = new g4photoelectricangulargenerator(); g4dummymodel\* dumm = new g4dummymodel(); g4wentzelvimodel\* wi = new g4wentzelvimodel(); g4epairproduction\* pair = new g4epairproduction(); g4uatomicdeexcitation\* deex = new g4uatomicdeexcitation(); g4ionparametrisedlossmodel\* ionl = new g4ionparametrisedlossmodel(); g4lindhardsorensenionmodel\* ion = new g4lindhardsorensenionmodel(); g4ionfluctuations\* ifluc = new g4ionfluctuations(); g4nuclearstopping\* ionstop = new g4nuclearstopping(); ionl->setminenergy(1*clhep::kev); ionl->setmaxenergy(100*clhep::mev); ion->setionmassregardingcoulombcorrection(); ion->setstopenergy(1.*clhep::mev); ifluc->settemperature(293.*clhep::kelvin); ifluc->setfluctuation(1.e-5); //ionstop->setmaxkinenergy(param->maxionenergy()); //ionstop->setmaxkinenergy(1.*clhep::mev); ionstop->setmaxkinenergy(1000.*clhep::ev); //ph->registerprocess(ionl, electron); //ph->registerprocess(ionstop, electron); //ph->registerprocess(ifluc, electron); //ph->registerprocess(coul, electron); //ph->registerprocess(pegen, electron); //ph->registerprocess(dumm, electron); //ph->registerprocess(wi, electron); //ph->registerprocess(pair, electron); //ph->registerprocess(deex, electron); } // add cosmic rays g4particledefinition\* cosmic = g4genericion::gyrozonal(); //g4ionparametrisedlossmodel\* cosloss = new g4ionparametrisedlossmodel("g4ionlosstable", "g4ionlosstable.txt"); //cosloss->setminenergy(1*clhep::kev); //cosloss->setmaxenergy(100*clhep::mev); //g4losstablemanager::instance()->setionlossmodel(cosloss); g4ionfluctuations\* cosfluct = new g4ionfluctuations(); cosfluct->setfluctuation(1.e-5); //g4densityfluctuations\* denfluct = new g4densityfluctuations("g4densfluct", .1,.2); g4coulombscattering\* coscs = new g4coulombscattering(); coscs->setemmodel(new g4dummymodel()); ph->registerprocess(coscs, cosmic); ph->registerprocess(cosfluct, cosmic); ph->registerprocess(new g4emultiplescattering, cosmic); ph->registerprocess(new g4eionisation, cosmic); ph->registerprocess(new g4ebremsstrahlung, cosmic); } // set defaults for all particle constructor g4emparameters\* param = g4emparameters::instance(); param->setdefaults(); param->setverbose(verboselevel); // set criteria for energy loss to be saved g4losstablemanager\* ltm = g4losstablemanager::instance());
assistant
br2->SetHighEnergyLimit(CLHEP::MeV); br1->SetLowEnergyLimit(CLHEP::GeV); br1->SetHighEnergyLimit(CLHEP::MeV); brem->SetUseRelativisticModel(true); eIoni->SetEmModel(br1); eIoni->SetEmModel(br2); eIoni->setLimitEnergy(0.001*CLHEP::MeV); G4EmBuilder::ConstructElectronProcess(eIoni, brem, msc1, nullptr, particle); ph->RegisterProcess(eIoni, particle); ph->RegisterProcess(brem, particle); // Add electron EM processes G4ParticleDefinition\* electron = G4Electron::Electron(); G4eMultipleScattering\* emsc = new G4eMultipleScattering(); emsc->SetStepLimit(new G4MscStepLimitType(1.e-6*CLHEP::m,1.e-6*CLHEP::m)); emsc->SetEmModel(msc1); G4eIonisation\* eIon = new G4eIonisation(); G4CoulombScattering\* coul = new G4CoulombScattering(); G4PhotoElectricAngularGenerator\* pegen = new G4PhotoElectricAngularGenerator(); G4DummyModel\* dumm = new G4DummyModel(); G4WentzelVIModel\* wi = new G4WentzelVIModel(); G4ePairProduction\* pair = new G4ePairProduction(); G4UAtomicDeexcitation\* deex = new G4UAtomicDeexcitation(); G4IonParametrisedLossModel\* ionl = new G4IonParametrisedLossModel(); G4LindhardSorensenIonModel\* ion = new G4LindhardSorensenIonModel(); G4IonFluctuations\* ifluc = new G4IonFluctuations(); G4NuclearStopping\* ionstop = new G4NuclearStopping(); ionl->SetMinEnergy(1*CLHEP::keV); ionl->SetMaxEnergy(100*CLHEP::MeV); ion->SetIonMassRegardingCoulombCorrection(); ion->SetStopEnergy(1.*CLHEP::MeV); ifluc->SetTemperature(293.*CLHEP::kelvin); ifluc->SetFluctuation(1.e-5); //ionstop->SetMaxKinEnergy(param->MaxIonEnergy()); //ionstop->SetMaxKinEnergy(1.*CLHEP::MeV); ionstop->SetMaxKinEnergy(1000.*CLHEP::eV); //ph->RegisterProcess(ionl, electron); //ph->RegisterProcess(ionstop, electron); //ph->RegisterProcess(ifluc, electron); //ph->RegisterProcess(coul, electron); //ph->RegisterProcess(pegen, electron); //ph->RegisterProcess(dumm, electron); //ph->RegisterProcess(wi, electron); //ph->RegisterProcess(pair, electron); //ph->RegisterProcess(deex, electron); } // Add cosmic rays G4ParticleDefinition\* cosmic = G4GenericIon::Gyrozonal(); //G4IonParametrisedLossModel\* cosloss = new G4IonParametrisedLossModel("G4IonLossTable", "G4IonLossTable.txt"); //cosloss->SetMinEnergy(1*CLHEP::keV); //cosloss->SetMaxEnergy(100*CLHEP::MeV); //G4LossTableManager::Instance()->SetIonLossModel(cosloss); G4IonFluctuations\* cosfluct = new G4IonFluctuations(); cosfluct->SetFluctuation(1.e-5); //G4DensityFluctuations\* denfluct = new G4DensityFluctuations("G4DensFluct", .1,.2); G4CoulombScattering\* coscs = new G4CoulombScattering(); coscs->SetEmModel(new G4DummyModel()); ph->RegisterProcess(coscs, cosmic); ph->RegisterProcess(cosfluct, cosmic); ph->RegisterProcess(new G4eMultipleScattering, cosmic); ph->RegisterProcess(new G4eIonisation, cosmic); ph->RegisterProcess(new G4eBremsstrahlung, cosmic); } // Set defaults for all particle constructor G4EmParameters\* param = G4EmParameters::Instance(); param->SetDefaults(); param->SetVerbose(verboseLevel); // set criteria for energy loss to be saved G4LossTableManager\* ltm = G4LossTableManager::Instance());
assistant