Geant4 has three virtual classes whose methods the user must override in order to implement a simulation. They require the user to define the detector, specify the physics to be used, and describe how initial particles are to be generated. G4VUserDetectorConstruction class G4VUserDetectorConstruction { public: G4VUserDetectorConstruction(); virtual ~G4VUserDetectorConstruction(); public: virtual G4VPhysicalVolume* Construct() = 0; }; G4VUserPhysicsList This is an abstract class for constructing particles and processes. The user must derive a concrete class from it and implement three virtual methods: ConstructParticle() to instantiate each requested particle type, ConstructPhysics() to instantiate the desired physics processes and register each of them with the process managers of the appropriate particles, and SetCuts(G4double aValue) to set a cut value in range for all particles in the particle table, which invokes the rebuilding of the physics table. When called, the Construct() method of G4VUserPhysicsList first invokes ConstructParticle() and then ConstructProcess(). The ConstructProcess() method must always invoke the AddTransportation() method in order to insure particle transportation. AddTransportation() must never be overridden. G4VUserPhysicsList provides several utility methods for the implementation of the above virtual methods. They are presented with comments in the class declaration in . class G4VUserPhysicsList { public: G4VUserPhysicsList(); virtual ~G4VUserPhysicsList(); public: // with description // By calling the "Construct" method, // particles and processes are created void Construct(); protected: // with description // These two methods of ConstructParticle() and ConstructProcess() // will be invoked in the Construct() method. // each particle type will be instantiated virtual void ConstructParticle() = 0; // each physics process will be instantiated and // registered to the process manager of each particle type virtual void ConstructProcess() = 0; protected: // with description // User must invoke this method in his ConstructProcess() // implementation in order to insures particle transportation. // !! Caution: this class must not be overriden !! void AddTransportation(); ///////////////////////////////////////////////////////////////// public: // with description // "SetCuts" method sets a cut value for all particle types // in the particle table virtual void SetCuts() = 0; public: // with description // set/get the default cut value // Calling SetDefaultCutValue causes re-calcuration of cut values // and physics tables just before the next event loop void SetDefaultCutValue(G4double newCutValue); G4double GetDefaultCutValue() const; ///////////////////////////////////////////////////////////////////// public: // with description // Invoke BuildPhysicsTable for all processes for all particles // In case of "Retrieve" flag is ON, PhysicsTable will be // retrieved from files void BuildPhysicsTable(); // do BuildPhysicsTable for specified particle type void BuildPhysicsTable(G4ParticleDefinition* ); // Store PhysicsTable together with both material and cut value // information in files under the specified directory. // (return true if files are sucessfully created) G4bool StorePhysicsTable(const G4String& directory = "."); // Return true if "Retrieve" flag is ON. // (i.e. PhysicsTable will be retrieved from files) G4bool IsPhysicsTableRetrieved() const; G4bool IsStoredInAscii() const; // Get directory path for physics table files. const G4String& GetPhysicsTableDirectory() const; // Set "Retrieve" flag // Directory path can be set together. // Null string (default) means directory is not changed // from the current value void SetPhysicsTableRetrieved(const G4String& directory = ""); void SetStoredInAscii(); // Reset "Retrieve" flag void ResetPhysicsTableRetrieved(); void ResetStoredInAscii(); /////////////////////////////////////////////////////////////////////// public: // with description // Print out the List of registered particles types void DumpList() const; public: // with description // Request to print out information of cut values // Printing will be performed when all tables are made void DumpCutValuesTable(G4int nParticles=3); // The following method actually trigger the print-out requested // by the above method. This method must be invoked by RunManager // at the proper moment. void DumpCutValuesTableIfRequested(); public: // with description void SetVerboseLevel(G4int value); G4int GetVerboseLevel() const; // set/get controle flag for output message // 0: Silent // 1: Warning message // 2: More /////////////////////////////////////////////////////////////////////////// public: // with description // "SetCutsWithDefault" method sets the default cut value // for all particles for the default region. void SetCutsWithDefault(); // Following are utility methods for SetCuts // SetCutValue sets a cut value for a particle type for the default region void SetCutValue(G4double aCut, const G4String& pname); // SetCutValue sets a cut value for a particle type for a region void SetCutValue(G4double aCut, const G4String& pname, const G4String& rname); // Invoke SetCuts for specified particle for a region // If the pointer to the region is NULL, the default region is used // In case of "Retrieve" flag is ON, // Cut values will be retrieved from files void SetParticleCuts(G4double cut,G4ParticleDefinition* particle,G4Region* region=0); // Invoke SetCuts for all particles in a region void SetCutsForRegion(G4double aCut, const G4String& rname); // Following are utility methods are obsolete void ResetCuts(); /////////////////////////////////////////////////////////////////// public: // Get/SetApplyCuts gets/sets the flag for ApplyCuts void SetApplyCuts(G4bool value, const G4String& name); G4bool GetApplyCuts(const G4String& name) const; /////////////////////////////////////////////////////////////////////////////// protected: // do BuildPhysicsTable for make the integral schema void BuildIntegralPhysicsTable(G4VProcess* ,G4ParticleDefinition* ); protected: // Retrieve PhysicsTable from files for proccess belongng the particle. // Normal BuildPhysics procedure of processes will be invoked, // if it fails (in case of Process's RetrievePhysicsTable returns false) virtual void RetrievePhysicsTable(G4ParticleDefinition* , const G4String& directory, G4bool ascii = false); ///////////////////////////////////////////////////////////////// protected: // adds new ProcessManager to all particles in the Particle Table // this routine is used in Construct() void InitializeProcessManager(); public: // with description // remove and delete ProcessManagers for all particles in tha Particle Table // this routine is invoked from RunManager void RemoveProcessManager(); public: // with description // add process manager for particles created on-the-fly void AddProcessManager(G4ParticleDefinition* newParticle, G4ProcessManager* newManager = 0 ); }; G4VUserPrimaryGeneratorAction class G4VUserPrimaryGeneratorAction { public: G4VUserPrimaryGeneratorAction(); virtual ~G4VUserPrimaryGeneratorAction(); public: virtual void GeneratePrimaries(G4Event* anEvent) = 0; };