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geant4/examples/extended/electromagnetic/TestEm7/include/G4ScreenedNuclearRecoil.hh
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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