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 /// \file G4ScreenedNuclearRecoil.hh
 /// \brief Definition of the G4ScreenedNuclearRecoil class
 
 // G4ScreenedNuclearRecoil.hh,v 1.24 2008/05/01 19:58:59 marcus Exp
 // GEANT4 tag
 //
 //
 //
 // Class Description
 // Process for screened electromagnetic nuclear elastic scattering;
 // Physics comes from:
 // Marcus H. Mendenhall and Robert A. Weller,
 // "Algorithms  for  the rapid  computation  of  classical  cross  sections
 // for  screened  Coulomb  collisions  "
 // Nuclear  Instruments  and  Methods  in  Physics  Research  B58  (1991)  11-17
 // The only input required is a screening function phi(r/a) which is the ratio
 // of the actual interatomic potential for two atoms with atomic numbers Z1 and
 // Z2,
 // to the unscreened potential Z1*Z2*e^2/r where e^2 is elm_coupling in Geant4
 // units
 // the actual screening tables are computed externally in a python module
 // "screened_scattering.py"
 // to allow very specific screening functions to be added if desired, without
 // messing with the insides of this code.
 //
 // First version, April 2004, Marcus H. Mendenhall, Vanderbilt University
 // May 1, 2008 -- Added code to allow process to have zero cross section above
 //  max energy, to coordinate with G4MSC.  -- mhm
 //
 // Class Description - End
 
 #ifndef G4ScreenedNuclearRecoil_h
 #define G4ScreenedNuclearRecoil_h 1
 
 #include "c2_function.hh"
 
 #include "G4ParticleChange.hh"
 #include "G4PhysicalConstants.hh"
 #include "G4SystemOfUnits.hh"
 #include "G4VDiscreteProcess.hh"
 #include "globals.hh"
 
 #include <map>
 #include <vector>
 
 class G4VNIELPartition;
 
 typedef c2_const_ptr<G4double> G4_c2_const_ptr;
 typedef c2_ptr<G4double> G4_c2_ptr;
 typedef c2_function<G4double> G4_c2_function;
 
 typedef struct G4ScreeningTables
 {
     G4double z1, z2, m1, m2, au, emin;
     G4_c2_const_ptr EMphiData;
 } G4ScreeningTables;
 
 // A class for loading ScreenedCoulombCrossSections
 class G4ScreenedCoulombCrossSectionInfo
 {
   public:
     G4ScreenedCoulombCrossSectionInfo() {}
     ~G4ScreenedCoulombCrossSectionInfo() {}
 
     static const char* CVSHeaderVers()
     {
       return "G4ScreenedNuclearRecoil.hh,v 1.24 2008/05/01 19:58:59 marcus Exp GEANT4 tag ";
     }
     static const char* CVSFileVers();
 };
 
 // A class for loading ScreenedCoulombCrossSections
 class G4ScreenedCoulombCrossSection : public G4ScreenedCoulombCrossSectionInfo
 {
   public:
     G4ScreenedCoulombCrossSection() : verbosity(1) {}
     G4ScreenedCoulombCrossSection(const G4ScreenedCoulombCrossSection& src)
       : G4ScreenedCoulombCrossSectionInfo(), verbosity(src.verbosity)
     {}
     virtual ~G4ScreenedCoulombCrossSection();
 
     typedef std::map<G4int, G4ScreeningTables> ScreeningMap;
 
     // a local, fast-access mapping of a particle's Z to its full definition
     typedef std::map<G4int, class G4ParticleDefinition*> ParticleCache;
 
     // LoadData is called by G4ScreenedNuclearRecoil::GetMeanFreePath
     // It loads the data tables, builds the elemental cross-section tables.
     virtual void LoadData(G4String screeningKey, G4int z1, G4double m1, G4double recoilCutoff) = 0;
 
     // BuildMFPTables is called by G4ScreenedNuclearRecoil::GetMeanFreePath
     // to build the MFP tables for each material
     void BuildMFPTables(void);  // scan the MaterialsTable and construct MFP
                                 // tables
 
     virtual G4ScreenedCoulombCrossSection* create() = 0;
     // a 'virtual constructor' which clones the class
     const G4ScreeningTables* GetScreening(G4int Z) { return &(screeningData[Z]); }
     void SetVerbosity(G4int v) { verbosity = v; }
 
     // this process needs element selection weighted only by number density
     G4ParticleDefinition* SelectRandomUnweightedTarget(const G4MaterialCutsCouple* couple);
 
     enum
     {
       nMassMapElements = 116
     };
 
     G4double standardmass(G4int z1) { return z1 <= nMassMapElements ? massmap[z1] : 2.5 * z1; }
 
     // get the mean-free-path table for the indexed material
     const G4_c2_function* operator[](G4int materialIndex)
     {
       return MFPTables.find(materialIndex) != MFPTables.end() ? &(MFPTables[materialIndex].get())
                                                               : (G4_c2_function*)0;
     }
 
   protected:
     ScreeningMap screeningData;  // screening tables for each element
     ParticleCache targetMap;
     G4int verbosity;
     std::map<G4int, G4_c2_const_ptr> sigmaMap;
     // total cross section for each element
     std::map<G4int, G4_c2_const_ptr> MFPTables;  // MFP for each material
 
   private:
     static const G4double massmap[nMassMapElements + 1];
 };
 
 typedef struct G4CoulombKinematicsInfo
 {
     G4double impactParameter;
     G4ScreenedCoulombCrossSection* crossSection;
     G4double a1, a2, sinTheta, cosTheta, sinZeta, cosZeta, eRecoil;
     G4ParticleDefinition* recoilIon;
     const G4Material* targetMaterial;
 } G4CoulombKinematicsInfo;
 
 class G4ScreenedCollisionStage
 {
   public:
     virtual void DoCollisionStep(class G4ScreenedNuclearRecoil* master, const class G4Track& aTrack,
                                  const class G4Step& aStep) = 0;
     virtual ~G4ScreenedCollisionStage() {}
 };
 
 class G4ScreenedCoulombClassicalKinematics : public G4ScreenedCoulombCrossSectionInfo,
                                              public G4ScreenedCollisionStage
 {
   public:
     G4ScreenedCoulombClassicalKinematics();
     virtual void DoCollisionStep(class G4ScreenedNuclearRecoil* master, const class G4Track& aTrack,
                                  const class G4Step& aStep);
 
     G4bool DoScreeningComputation(class G4ScreenedNuclearRecoil* master,
                                   const G4ScreeningTables* screen, G4double eps, G4double beta);
 
     virtual ~G4ScreenedCoulombClassicalKinematics() {}
 
   protected:
     // the c2_functions we need to do the work.
     c2_const_plugin_function_p<G4double>& phifunc;
     c2_linear_p<G4double>& xovereps;
     G4_c2_ptr diff;
 };
 
 class G4SingleScatter : public G4ScreenedCoulombCrossSectionInfo, public G4ScreenedCollisionStage
 {
   public:
     G4SingleScatter() {}
     virtual void DoCollisionStep(class G4ScreenedNuclearRecoil* master, const class G4Track& aTrack,
                                  const class G4Step& aStep);
     virtual ~G4SingleScatter() {}
 };
 
 /**
      \brief A process which handles screened Coulomb collisions between nuclei
 
 */
 
 class G4ScreenedNuclearRecoil : public G4ScreenedCoulombCrossSectionInfo, public G4VDiscreteProcess
 {
   public:
     friend class G4ScreenedCollisionStage;
 
     /// \param processName the name to assign the process
     /// \param ScreeningKey the name of a screening function to use.
     /// The default functions are "zbl" (recommended for soft scattering),
     /// "lj" (recommended for backscattering) and "mol" (Moliere potential)
     /// \param GenerateRecoils if frue, ions struck by primary are converted
     /// into new moving particles.
     /// If false, energy is deposited, but no new moving ions are created.
     /// \param RecoilCutoff energy below which no new moving particles will be
     /// created, even if a GenerateRecoils is true.
     /// Also, a moving primary particle will be stopped if its energy falls
     /// below this limit.
     /// \param PhysicsCutoff the energy transfer to which screening tables are
     /// calucalted.
     /// There is no really
     /// compelling reason to change it from the 10.0 eV default.
     /// However, see the paper on running this
     /// in thin targets for further discussion, and its interaction
     /// with SetMFPScaling()
 
     G4ScreenedNuclearRecoil(const G4String& processName = "ScreenedElastic",
                             const G4String& ScreeningKey = "zbl", G4bool GenerateRecoils = 1,
                             G4double RecoilCutoff = 100.0 * eV, G4double PhysicsCutoff = 10.0 * eV);
 
     virtual ~G4ScreenedNuclearRecoil();
 
     virtual G4double GetMeanFreePath(const G4Track&, G4double, G4ForceCondition*);
 
     virtual G4VParticleChange* PostStepDoIt(const G4Track& aTrack, const G4Step& aStep);
     /// \param aParticleType the particle to test
     virtual G4bool IsApplicable(const G4ParticleDefinition& aParticleType);
     /// \param aParticleType the type of particle to build tables for
     virtual void BuildPhysicsTable(const G4ParticleDefinition& aParticleType);
     /// \param aParticleType the type of particle to build tables for
     virtual void DumpPhysicsTable(const G4ParticleDefinition& aParticleType);
     /// range of the selected nucleus
     /// \param A the nucleon number of the beam
     /// \param A1 the nucleon number of the target
     /// \param apsis the distance of closest approach
 
     virtual G4bool CheckNuclearCollision(G4double A, G4double A1,
                                          G4double apsis);  // return true if hard collision
 
     virtual G4ScreenedCoulombCrossSection* GetNewCrossSectionHandler(void);
 
     G4double GetNIEL() const { return NIEL; }
 
     void ResetTables();
     // clear all data tables to allow changing energy cutoff, materials, etc.
 
     /// cross section
     ///
     /// This funciton is used to coordinate this process with G4MSC.
     /// Typically, G4MSC should
     /// not be allowed to operate in a range which overlaps that of this
     /// process.  The criterion which is most reasonable
     /// is that the transition should be somewhere in the modestly
     /// relativistic regime (500 MeV/u for example).
     /// param energy energy per nucleon for the cutoff
 
     void SetMaxEnergyForScattering(G4double energy) { processMaxEnergy = energy; }
 
     std::string GetScreeningKey() const { return screeningKey; }
 
     /// \param flag if true, enable deposition of energy (the default).
     /// If false, disable deposition.
 
     void AllowEnergyDeposition(G4bool flag) { registerDepositedEnergy = flag; }
 
     G4bool GetAllowEnergyDeposition() const { return registerDepositedEnergy; }
 
     /// If recoils are disabled, the energy they would have received is just
     /// deposited.
     /// param flag if true, create recoil ions in cases in which the energy
     /// is above the recoilCutoff.
     /// If false, just deposit the energy.
 
     void EnableRecoils(G4bool flag) { generateRecoils = flag; }
 
     G4bool GetEnableRecoils() const { return generateRecoils; }
 
     /// \param scale the factor by which the default MFP will be scaled.
     /// Set to less than 1 for very thin films, typically,
     /// to sample multiple scattering,
     /// or to greater than 1 for quick simulations with a very long flight path
 
     void SetMFPScaling(G4double scale) { MFPScale = scale; }
 
     G4double GetMFPScaling() const { return MFPScale; }
 
     /// which are close enough they need hadronic phsyics.
     /// Default is true (skip close collisions).
     /// Disabling this results in excess nuclear stopping power.
     /// \param flag true results in hard collisions being skipped.
     /// false allows hard collisions.
 
     void AvoidNuclearReactions(G4bool flag) { avoidReactions = flag; }
 
     G4bool GetAvoidNuclearReactions() const { return avoidReactions; }
 
     /// be generated,
     /// and the energy (per nucleon) below which all ions are stopped.
     /// \param energy energy per nucleon
 
     void SetRecoilCutoff(G4double energy) { recoilCutoff = energy; }
 
     G4double GetRecoilCutoff() const { return recoilCutoff; }
 
     /// Typically, this is 10 eV or so, and not often changed.
     /// \param energy the cutoff energy
 
     void SetPhysicsCutoff(G4double energy)
     {
       physicsCutoff = energy;
       ResetTables();
     }
 
     G4double GetPhysicsCutoff() const { return physicsCutoff; }
 
 
     void SetNIELPartitionFunction(const G4VNIELPartition* part);
 
     /// backscattering
     /// \param fraction the fraction of particles to have their cross section
     /// boosted.
     /// \param HardeningFactor the factor by which to boost the scattering
     /// cross section.
 
     void SetCrossSectionHardening(G4double fraction, G4double HardeningFactor)
     {
       hardeningFraction = fraction;
       hardeningFactor = HardeningFactor;
     }
 
     G4double GetHardeningFraction() const { return hardeningFraction; }
 
     G4double GetHardeningFactor() const { return hardeningFactor; }
 
     G4double GetCurrentInteractionLength() const { return currentInteractionLength; }
 
     /// if the user needs non-standard behavior.
     /// \param cs a class which constructs the screening tables.
 
     void SetExternalCrossSectionHandler(G4ScreenedCoulombCrossSection* cs)
     {
       externalCrossSectionConstructor = cs;
     }
 
     G4int GetVerboseLevel() const { return verboseLevel; }
 
     std::map<G4int, G4ScreenedCoulombCrossSection*>& GetCrossSectionHandlers()
     {
       return crossSectionHandlers;
     }
 
     void ClearStages(void);
 
     void AddStage(G4ScreenedCollisionStage* stage) { collisionStages.push_back(stage); }
 
     G4CoulombKinematicsInfo& GetKinematics() { return kinematics; }
 
     void SetValidCollision(G4bool flag) { validCollision = flag; }
 
     G4bool GetValidCollision() const { return validCollision; }
 
     /// for internal use, primarily.
     class G4ParticleChange& GetParticleChange()
     {
       return static_cast<G4ParticleChange&>(*pParticleChange);
     }
 
     /// to partition it into NIEL and ionizing energy.
 
     void DepositEnergy(G4int z1, G4double a1, const G4Material* material, G4double energy);
 
   protected:
     G4double highEnergyLimit;
 
     G4double lowEnergyLimit;
 
     /// to cross over to G4MSC
     G4double processMaxEnergy;
     G4String screeningKey;
     G4bool generateRecoils, avoidReactions;
     G4double recoilCutoff, physicsCutoff;
     G4bool registerDepositedEnergy;
     G4double IonizingLoss, NIEL;
     G4double MFPScale;
     G4double hardeningFraction, hardeningFactor;
 
     G4ScreenedCoulombCrossSection* externalCrossSectionConstructor;
     std::vector<G4ScreenedCollisionStage*> collisionStages;
 
     std::map<G4int, G4ScreenedCoulombCrossSection*> crossSectionHandlers;
 
     G4bool validCollision;
     G4CoulombKinematicsInfo kinematics;
     const G4VNIELPartition* NIELPartitionFunction;
 };
 
 // A customized G4CrossSectionHandler which gets its data from
 // an external program
 
 class G4NativeScreenedCoulombCrossSection : public G4ScreenedCoulombCrossSection
 {
   public:
     G4NativeScreenedCoulombCrossSection();
 
     G4NativeScreenedCoulombCrossSection(const G4NativeScreenedCoulombCrossSection& src)
       : G4ScreenedCoulombCrossSection(src), phiMap(src.phiMap)
     {}
 
     G4NativeScreenedCoulombCrossSection(const G4ScreenedCoulombCrossSection& src)
       : G4ScreenedCoulombCrossSection(src)
     {}
 
     virtual ~G4NativeScreenedCoulombCrossSection();
 
     virtual void LoadData(G4String screeningKey, G4int z1, G4double m1, G4double recoilCutoff);
 
     virtual G4ScreenedCoulombCrossSection* create()
     {
       return new G4NativeScreenedCoulombCrossSection(*this);
     }
 
     // get a list of available keys
     std::vector<G4String> GetScreeningKeys() const;
 
     typedef G4_c2_function& (*ScreeningFunc)(G4int z1, G4int z2, size_t nPoints, G4double rMax,
                                              G4double* au);
 
     void AddScreeningFunction(G4String name, ScreeningFunc fn) { phiMap[name] = fn; }
 
   private:
     // this is a map used to look up screening function generators
     std::map<std::string, ScreeningFunc> phiMap;
 };
 
 G4_c2_function& ZBLScreening(G4int z1, G4int z2, size_t npoints, G4double rMax, G4double* auval);
 
 G4_c2_function& MoliereScreening(G4int z1, G4int z2, size_t npoints, G4double rMax,
                                  G4double* auval);
 
 G4_c2_function& LJScreening(G4int z1, G4int z2, size_t npoints, G4double rMax, G4double* auval);
 
 G4_c2_function& LJZBLScreening(G4int z1, G4int z2, size_t npoints, G4double rMax, G4double* auval);
 
 #endif

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